Computing Acronyms
Acronyms common in computing, hacker culture, and everyday software engineering conversations. This section collects concise definitions and quick examples to help you grok the jargon fast. A note about the legacy/historical subsections:
- Legacy: outdated but still in use.
- Historical: obsolete, mostly of historical interest.
Software Architecture
Acronym | Meaning | Example |
---|---|---|
C4 | Context–Container–Component–Code — lightweight hierarchical diagramming model for communicating software architecture at multiple levels of abstraction. | Draw a system Context and Container diagram for a web app; break a service into Components; optionally add Code-level diagrams. |
CQRS | Command Query Responsibility Segregation — separate writes/reads. | Write model emits events; read model is a projection. |
ECS | Entity Component System — decompose game and simulation logic into data-only components processed by systems operating on matching entities. | Game engine with Position /Velocity components updated by a PhysicsSystem ; rendering system consumes Mesh components. |
EDA | Event-Driven Architecture — async event-based systems. | Publish domain events to Kafka; services react. |
ES | Event Sourcing — persist state changes as an append‑only log of events and rebuild current state by replaying them. | Order aggregate applies OrderPlaced /ItemAdded events; projections update read models. |
SOA | Service-Oriented Architecture — collaborating services. | Decompose monolith into services. |
Legacy | ||
COM | Component Object Model — Microsoft binary-interface standard for reusable components with reference counting and interface-based polymorphism. | Query IUnknown /IDispatch ; register COM servers; Office automation via COM. |
COM+ | Component Services — evolution of COM/DCOM on Windows that adds declarative transactions, role-based security, queued components, and pooled object activation managed by the OS. | Configure COM+ applications in Component Services MMC; legacy enterprise apps use COM+ transactions and queued components before .NET. |
DCOM | Distributed COM — extension of COM for inter-process and cross-machine communication using RPC. | Remote COM server activation/config over the network using DCOMCNFG. |
DDE | Dynamic Data Exchange — legacy Windows message-based mechanism for applications to exchange data and commands via shared memory conversations; superseded by OLE/COM automation. | Early Windows apps used DDE for live spreadsheet/word processor links; replaced by OLE automation and modern IPC. |
EJB | Enterprise JavaBeans — server-side component model for building distributed, transactional applications in Java; heavyweight and largely superseded by lighter frameworks. | Session Beans, Entity Beans, MDBs in a Java EE/Jakarta EE application server. |
ESB | Enterprise Service Bus — centralized integration/message bus with mediation, routing, and governance typical of classic SOA; considered heavyweight today. | Hub‑and‑spoke integration; replaced by microservices and event streaming (Kafka). |
MAPI | Messaging Application Programming Interface — Windows component API for email, calendaring, and messaging integration, primarily used by Microsoft Exchange/Outlook clients. | Outlook talks to Exchange via Extended MAPI; legacy apps used Simple MAPI to open/send mail through the default client. |
MOM | Message-Oriented Middleware — infrastructure for asynchronous communication between distributed systems via messages and queues, decoupling producers and consumers. | IBM MQ, TIBCO, MSMQ; modern equivalents include Kafka and RabbitMQ. |
MSMQ | Microsoft Message Queuing — durable asynchronous messaging middleware built into Windows that provides store-and-forward queues with transactional and secure delivery. | Legacy enterprise apps used MSMQ to decouple services; integrates with COM+, WCF, and bridge adapters for REST/HTTP. |
OCX | OLE Control Extension — a legacy Microsoft standard for reusable software components based on COM/OLE, the predecessor to ActiveX controls. | Embedding third-party UI controls (.ocx files) in Visual Basic 6 applications. |
SOAP | XML-based messaging protocol for web services. | Enterprise integrations over SOAP. |
WCF | Windows Communication Foundation — a legacy .NET framework for building service-oriented applications. | Superseded by gRPC and ASP.NET Core Web API. |
WF | Windows Workflow Foundation — a legacy .NET framework for building workflow-based applications. | State machine or sequential workflows in older .NET applications. |
Historical | ||
CORBA | Common Object Request Broker Architecture — OMG standard for language- and platform-neutral distributed objects communicating via an Object Request Broker. | Define interfaces in IDL; ORB uses IIOP for interop between stubs and skeletons. |
DCE | Distributed Computing Environment — OSF framework for distributed applications providing RPC, security (Kerberos), directory, and threading services. | Build client/server apps with DCE RPC; secure with GSSAPI; use CDS for naming. |
Software Design
Acronym | Meaning | Example |
---|---|---|
AoS | Array of Structs — contiguous collection where each element stores all fields, offering good spatial locality for per-entity operations. | struct Particle { float x, y, z; } particles[N]; iterate once to update position/velocity. |
CPS | Continuation-Passing Style — express control flow by passing an explicit continuation function instead of returning normally. | f(x, k) calls k(result) ; enables tail calls, trampolines, async composition. |
CSP | Communicating Sequential Processes — formal concurrency model where independent processes interact solely via message‑passing over channels (no shared memory). | Go channels/select and occam are CSP‑inspired; model systems as processes and rendezvous on channels. |
DDD | Domain-Driven Design — model around the domain. | Ubiquitous language in code and docs. |
DI | Dependency Injection — provide dependencies from the outside rather than creating them inside. | Pass a Logger to a service constructor instead of instantiating it. |
DIP | Dependency Inversion Principle — depend on abstractions, not concretions. | Accept a Logger interface, not a concrete ConsoleLogger . |
DRY | Don't Repeat Yourself — avoid duplicating knowledge in code and docs. | Extract a function instead of pasting the same block twice. |
DTO | Data Transfer Object — simple data container. | Map entities to DTOs for API responses. |
FRP | Functional Reactive Programming — model time‑varying values and event streams with functional operators. | UI state as RxJS Observables using map/merge/switchMap . |
ISP | Interface Segregation Principle — prefer many small, client‑specific interfaces. | Use Readable /Writable instead of a bloated File interface. |
KISS | Keep It Simple, Stupid — prefer simple solutions that meet requirements. | Use a plain function instead of a custom class hierarchy. |
LSP | Liskov Substitution Principle — subtypes must be substitutable for their base. | A subclass shouldn't strengthen preconditions or weaken postconditions. |
MVC | Model–View–Controller — separate data, presentation, and control flow. | Controllers orchestrate; Views render; Models hold domain data. |
MVVM | Model–View–ViewModel — bind UI to a ViewModel that exposes state/actions. | Two-way binding in front-end frameworks. |
OCP | Open/Closed Principle — open for extension, closed for modification. | Add a new strategy class instead of editing a switch. |
SDI | Single-Document Interface — application model where each document is opened in its own separate top-level window. | Web browsers, VS Code; each window is an independent instance. |
SoA | Struct of Arrays — layout that keeps each field in its own contiguous array to enable SIMD/vectorization and cache-friendly columnar processing. | Separate x[N] , y[N] , z[N] arrays for particles to update components with wide vector loads. |
SoC | Separation of Concerns — isolate responsibilities into distinct modules. | Keep validation, business logic, and persistence in separate layers. |
SOLID | Five OO design principles: SRP, OCP, LSP, ISP, DIP. | Extract interfaces and inject dependencies via constructors. |
SRP | Single Responsibility Principle — one reason to change. | Split parsing and rendering into separate classes. |
UML | Unified Modeling Language — notation to visualize/design systems. | Class and sequence diagrams for architecture and behavior. |
WET | Write Everything Twice — tongue-in-cheek opposite of DRY. | Duplicate code rather than refactor. |
WIMP | Windows, Icons, Menus, Pointer — classic graphical user interface paradigm built around overlapping windows, iconography, menu bars, and a pointing device. | Xerox Star and Apple Macintosh popularized WIMP desktops; modern desktop OSes retain the model. |
YAGNI | You Aren't Gonna Need It — don't build features until necessary. | Skip a caching layer until profiling shows the need. |
Legacy | ||
MDI | Multiple-Document Interface — application model where multiple child windows are contained within a single parent window. | Classic desktop apps (early Photoshop/Office); child windows for each document. |
Software Engineering
Acronym | Meaning | Example |
---|---|---|
BDD | Behavior-Driven Development — specify behavior in examples (Given/When/Then). | Feature files drive implementation and acceptance tests. |
BDUF | Big Design Up Front — invest in upfront architecture/design before implementation. | Comprehensive UML/specs prior to coding (vs iterative/agile). |
CD | Continuous Delivery/Deployment — automated release pipeline to ship safely. | Tagging main triggers a production deploy. |
CI | Continuous Integration — frequently merge to main with automated tests. | Every PR runs unit and integration tests in CI. |
CI/CD | Combined practice of Continuous Integration and Delivery/Deployment. | Build, test, artifact, deploy stages in one pipeline. |
DSC | Desired State Configuration — declarative configuration management approach that defines the target state and lets tooling converge systems to it continually. | PowerShell DSC or Azure Automanage enforces web server configs by applying declarative manifests and reporting drift. |
DX | Developer Experience — overall quality of tools, workflows, and docs that make developers productive and happy. | One‑command setup, fast feedback loops, clear errors, great CLIs. |
E2E | End-to-End — tests or flows that cover the full user journey across systems and components. | Cypress/Playwright tests from UI through API to DB. |
EOL | End Of Life — product/version no longer supported with fixes or updates; plan upgrades before EOL to remain secure and compliant. | Ubuntu 20.04 reaches EOL → migrate to 22.04 LTS. |
GA | General Availability — broad production release status following beta/RC; officially supported. | Mark v1.0 as GA and enable default rollout. |
HCI | Human-Computer Interaction — discipline focused on designing, evaluating, and implementing user interfaces and human-centered systems. | Usability studies, prototyping flows, accessibility reviews for a new feature. |
I18N | Internationalization — design for multiple languages/locales. | Externalize strings; ICU formatting; locale-aware dates/numbers. |
ICU | International Components for Unicode — a mature and widely used set of C/C++ and Java libraries for Unicode support, internationalization, and globalization. | Use ICU for collation, date/time formatting, and character set conversion. |
KPI | Key Performance Indicator — metric tracking performance toward a goal. | Conversion rate, p95 latency, crash-free sessions. |
L10N | Localization — adapt an internationalized product for a locale. | Translate resources; RTL layout; localized units/images. |
LTS | Long-Term Support — release line maintained with security/critical fixes for an extended period. | Choose Node.js LTS for production; receive patches without feature churn. |
MQ | Merge Queue — automation that sequences merges and runs required checks on up-to-date commits so main stays green. | GitHub/GitLab merge queue rebases the next PR onto main, runs CI, and auto-merges when green. |
MVP | Minimum Viable Product — smallest thing to deliver value/learning. | Ship a CLI prototype before a full GUI. |
OKR | Objectives and Key Results — align goals and track outcomes. | Company-level objectives with measurable KRs. |
PoC | Proof of Concept — quick prototype to validate feasibility. | Spike code to test a new database driver. |
PR | Pull Request — propose code change for review/merge. | Open a PR for CI checks and team review. |
QA | Quality Assurance — practices to ensure product quality via process and testing. | Test plans, manual/exploratory testing, and sign-off before release. |
RAD | Rapid Application Development — iterative, prototyping‑focused approach emphasizing quick delivery and user feedback over heavy upfront planning. | Build a working prototype with low‑code/4GL tools and iterate with users. |
RC | Release Candidate — build believed to be release‑ready, pending final validation. | Ship RC to staging for UAT and smoke tests. |
RFC | Request For Comments — proposal/spec for feedback before adoption. | RFC for a breaking API change. |
SCM | Source Control Management — processes/tools for tracking changes to source code and related assets; often used interchangeably with VCS. | Git as an SCM; branching strategies, code reviews, and CI integration. |
SDLC | Software Development Life Cycle — structured process for planning, designing, building, testing, deploying, and maintaining software. | Phases: requirements → design → implementation → testing → deployment → maintenance. |
SWE | Software Engineer — practitioner who designs, builds, tests, and maintains software systems. | Full‑stack SWE implementing features, writing tests, and doing code reviews. |
TDD | Test-Driven Development — write a failing test, pass it, refactor. | Red → Green → Refactor per behavior. |
UAT | User Acceptance Testing — end users validate requirements. | Business stakeholders test before release. |
UI | User Interface — the visual and interactive surface users operate. | Screens, components, and controls in web/mobile apps. |
UX | User Experience — usability and satisfaction. | Research, UX writing, usability testing. |
VCS | Version Control System — track changes to code and collaborate. | Git (branches, commits, PRs), Mercurial. |
WIP | Work In Progress — items in progress; limit to improve flow. | Cap WIP per Kanban column. |
XP | Extreme Programming — agile practices emphasizing feedback/simplicity. | Pair programming, CI, refactoring, and TDD. |
Legacy | ||
CVS | Concurrent Versions System — an early, influential client-server version control system that popularized features like branching and merging. | Superseded by Subversion (SVN) and later Git. |
Historical | ||
Y2K | Year 2000 problem — class of bugs related to storing years with two digits, causing issues with dates in and after the year 2000. | Remediation projects to expand date fields and fix date logic. |
Web Development
Acronym | Meaning | Example |
---|---|---|
AJAX | Asynchronous JavaScript and XML — async HTTP from the browser. | Fetch data without full page reload. |
ARIA | Accessible Rich Internet Applications — a W3C specification for making web content and applications more accessible to people with disabilities. | Use role="button" and aria-label to make a <div> accessible as a button. |
ASGI | Asynchronous Server Gateway Interface — the modern, async-capable successor to WSGI for Python web applications. | Run a FastAPI or Django 3+ app with Uvicorn. |
ASP.NET | Active Server Pages .NET — Microsoft's web application framework for building dynamic web sites and services with languages like C#. | Build web APIs and Razor Pages with ASP.NET Core. |
CMS | Content Management System — application for creating, managing, and publishing website content, often with roles, workflows, and plugins; headless CMS expose content via APIs. | WordPress/Drupal; headless CMS like Contentful/Sanity. |
CSR | Client-Side Rendering — render in the browser via JS. | React SPA renders views on the client. |
CSS | Cascading Style Sheets — style language for HTML. | Tailwind/vanilla CSS styles pages. |
DOM | Document Object Model — tree for HTML/XML. | document.querySelector() manipulates nodes. |
ES | ECMAScript — JavaScript specification. | ES2023 features. |
GraphQL | Query language/runtime for typed APIs. | Client requests specific fields only. |
HTML | HyperText Markup Language — web markup. | <div> , <a> , <section> structure pages. |
IIS | Internet Information Services — Microsoft's web server software for Windows. | Host ASP.NET applications on Windows Server with IIS. |
JS | JavaScript — language of the web. | Frontend apps, Node.js scripts. |
LTR | Left-To-Right — text direction where writing proceeds from left to right; default for Latin scripts. | HTML dir="ltr" ; ensure proper bidi handling with Unicode markers where needed. |
NPM | Node Package Manager — default package manager and registry client for Node.js, distributing JavaScript packages and managing project dependencies/scripts. | npm install react adds dependencies; package.json defines scripts run via npm run build . |
OpenAPI | Standard to describe HTTP APIs (Swagger). | Generate clients from openapi.yaml . |
PWA | Progressive Web App — offline/installable web app. | Add service worker and manifest. |
REST | Representational State Transfer — resource APIs. | GET /posts/42 returns a Post. |
RTL | Right-To-Left — text direction where writing proceeds from right to left; used by scripts like Arabic and Hebrew. | HTML dir="rtl" ; use logical CSS properties (margin-inline-start ) for bidi layouts. |
SEO | Search Engine Optimization — improve visibility/traffic. | Add metadata; optimize content. |
SPA | Single Page Application — dynamic single page. | React/Vue app with client routing. |
SSR | Server-Side Rendering — render HTML on server. | Next.js SSR pages. |
TS | TypeScript — typed superset of JavaScript that compiles to plain JS. | Add static types/interfaces; transpile with tsc or bundlers. |
UA | User Agent — identifier string a client sends describing the software, version, and sometimes device/OS. | HTTP User-Agent header; spoof/rotate UA for testing/scraping. |
URI | Uniform Resource Identifier — generic identifier for names/addresses of resources; includes URLs (locators) and URNs (names). | mailto:hello@example.com , urn:isbn:9780143127796 , https://example.com/ . |
URL | Uniform Resource Locator — reference (address) to resources on a network using a scheme, host, and path. | https://example.com/docs/index.html . |
URN | Uniform Resource Name — a URI that names a resource without specifying its location; persistent, location‑independent identifiers. | urn:isbn:9780143127796 , urn:uuid:123e4567-e89b-12d3-a456-426614174000 . |
WASM | WebAssembly — portable fast binary format. | Run Rust/C++ in the browser. |
WCAG | Web Content Accessibility Guidelines — the primary international standard for web accessibility, published by the W3C. | Aim for WCAG 2.1 AA compliance with sufficient color contrast and keyboard navigation. |
WSGI | Web Server Gateway Interface — the standard interface between Python web applications and web servers. | Gunicorn/uWSGI running a Flask/Django app via a WSGI callable. |
WWW | World Wide Web — system of interlinked hypertext documents and resources accessed via the internet using HTTP(S) and URLs. | Browse websites over HTTPS with a web browser. |
Legacy | ||
ASP | Active Server Pages — Microsoft's first server-side script engine for dynamically generated web pages; superseded by ASP.NET. | Classic ASP with VBScript (<% ... %> ) on IIS. |
CGI | Common Gateway Interface — standard for web servers to execute external programs and generate dynamic content. | Apache invoking a CGI script to render a page. |
IE | Internet Explorer — Microsoft's legacy web browser, superseded by Edge. | IE11 compatibility mode; legacy intranet sites requiring ActiveX. |
JSP | Jakarta Server Pages (JavaServer Pages) — a technology for creating dynamically generated web pages with Java code embedded in HTML. | .jsp files compiled into servlets on a Java application server. |
WSDL | Web Services Description Language — an XML-based interface definition language for describing the functionality of a SOAP web service. | Generate a client proxy from a .wsdl file; ?wsdl endpoint on a SOAP service. |
XHR | XMLHttpRequest — legacy browser API for making HTTP requests from JavaScript (superseded by fetch ). | xhr.open('GET', '/api') ; handle onreadystatechange . |
Programming Languages
Acronym | Meaning | Example |
---|---|---|
PHP | PHP: Hypertext Preprocessor — a widely-used open source general-purpose scripting language that is especially suited for web development. | WordPress, Laravel, and Symfony are built with PHP. |
VB.NET | Visual Basic .NET — the modern, object-oriented successor to classic VB, running on the .NET platform. | Build Windows Forms or ASP.NET applications with VB.NET. |
VBA | Visual Basic for Applications — the scripting language for Microsoft Office, used for automation and macros. | Automate Excel reports with VBA macros in the VBE. |
Legacy | ||
APL | A Programming Language — an array-oriented language known for its concise syntax using a special character set. | Financial modeling and data manipulation with APL's vector and matrix operations. |
AWK | Aho, Weinberger, and Kernighan — a domain-specific language for text processing, typically used for data extraction and reporting. | awk '{print $1}' file.txt to print the first column of a file. |
BASIC | Beginner's All-purpose Symbolic Instruction Code — simple, interactive language designed for accessibility, popular on microcomputers. | 10 PRINT "HELLO" , 20 GOTO 10 ; Microsoft BASIC, Dartmouth BASIC. |
COBOL | COmmon Business-Oriented Language — verbose, English-like language for business, finance, and administrative systems on mainframes. | IDENTIFICATION DIVISION. , PERFORM ... UNTIL ... ; legacy financial systems. |
FORTRAN | FORmula TRANslation — pioneering compiled language for numeric and scientific computing. | DO loops, GOTO , COMMON blocks; used in HPC and scientific libraries. |
LISP | LISt Processing — early, influential high-level language family based on lambda calculus, pioneering many FP concepts and featuring code-as-data (homoiconicity). | (defun factorial (n) ...) in Common Lisp/Scheme; Emacs Lisp. |
ML | MetaLanguage — an influential family of functional programming languages known for its static type system, type inference, and algebraic data types. | Standard ML (SML) and OCaml are popular dialects; influenced F#, Rust, and Haskell. |
PL/I | Programming Language One — an imperative language developed by IBM for scientific, engineering, and business applications, combining features from FORTRAN and COBOL. | Legacy applications on IBM mainframes (z/OS). |
RPG | Report Program Generator — a high-level language for business applications, primarily on IBM i (AS/400) systems. | Business logic in fixed-format RPG IV on an IBM iSeries server. |
SML | Standard ML — a popular dialect of the ML programming language, known for its formal definition and use in language research. | SML/NJ and MLton are common compilers; used in theorem provers. |
VB | Visual Basic (Classic) — event-driven language and IDE for rapid application development on Windows before .NET. | VB6 applications with COM components and ADO database connections. |
Historical | ||
ALGOL | ALGOrithmic Language — influential early family of imperative languages that introduced block structure, lexical scope, and formal grammar definition (BNF). | ALGOL 60/68 influenced Pascal, C, and many other languages. |
Programming
Acronym | Meaning | Example |
---|---|---|
AAA | Arrange–Act–Assert — unit testing pattern that structures tests into setup (arrange inputs/fixtures), execution (act), and verification (assert expected outcomes). | Arrange a service and mocks; Act by calling the method; Assert on result and interactions. |
ADT | Abstract Data Type — specification of behavior independent of implementation. | Stack/queue ADTs with array- or list-based implementations. |
ADT | Algebraic Data Type — composite types formed by sums (variants) and products (fields), enabling expressive, type-safe modeling. | Rust enums/Haskell data types; Option/Either in FP. |
AIO | Asynchronous I/O — a form of I/O processing that permits other processing to continue before the transmission has finished. | Linux io_uring or Windows IOCP for high-performance servers. |
API | Application Programming Interface — a defined surface for one piece of software to interact with another. | POSIX file APIs, a graphics library API, or an HTTP endpoint. |
ASM | Assembly Language — low-level programming language with a strong correspondence between instructions and the machine's architecture. | Write syscall wrappers in ASM; optimize hot loops with SIMD intrinsics or inline assembly. |
AVL | Adelson-Velsky and Landis tree — self‑balancing binary search tree that maintains height balance via rotations to ensure O(log n) search/insert/delete. | Implement an ordered map/set with AVL rotations (LL/LR/RL/RR). |
BAR | Base Address Register — PCI/PCIe register that stores the base address and size of a device resource so the host can map memory-mapped I/O or port ranges into the system address space. | GPUs/network cards expose VRAM or control registers via BARs; "Resizable BAR" allows mapping full GPU memory on modern systems. |
BCL | Base Class Library — the standard library of core types and functions in the .NET Framework and its successors. | Use types from System namespace like String , List<T> , and HttpClient . |
BEAM | Bogdan's Erlang Abstract Machine — the virtual machine at the core of the Erlang and Elixir ecosystems, known for its concurrency and fault tolerance. | The BEAM VM powers highly concurrent systems like WhatsApp. |
BFS | Breadth-First Search — graph/tree traversal that visits neighbors level by level using a queue; finds shortest paths in unweighted graphs. | Level-order traversal of a tree; BFS from a source to compute distances/parents. |
BSP | Binary Space Partitioning — recursively subdivide space with hyperplanes (planes in 3D, lines in 2D) to organize geometry for visibility, rendering order, and collision queries. | Classic FPS engines (e.g., Quake) use BSP trees for visibility/culling and painter's algorithm ordering. |
BST | Binary Search Tree — ordered binary tree supporting average O(log n) search/insert/delete when balanced; worst‑case O(n) if unbalanced. | Implement sets/maps; inorder traversal yields keys in sorted order. |
CAS | Compare-And-Swap — atomic operation that updates a memory location only if it still equals an expected value; foundation for lock‑free algorithms. | CAS loop for a lock‑free stack push; beware the ABA problem. |
CLI | Command-Line Interface — text-based commands. | git , kubectl , custom CLIs. |
CLI | Common Language Infrastructure — the open specification (ECMA-335) for the .NET runtime environment. | The .NET CLR is an implementation of the CLI standard. |
CLR | Common Language Runtime — .NET VM. | Runs C# assemblies. |
CRUD | Create, Read, Update, Delete — basic data ops. | REST endpoints map to CRUD on users . |
CUI | Character User Interface — text/character-based UI typically rendered in terminals with limited graphics; overlaps with TUI. | Installer wizards and ncurses-style menus in a terminal. |
DAG | Directed Acyclic Graph — directed graph with no cycles; commonly used to model dependencies and enable topological ordering in compilers, build systems, and task scheduling. | Topologically sort to order compilation units; represent dependencies in build graphs or AST passes. |
DFS | Depth-First Search — graph/tree traversal that explores as far as possible along each branch before backtracking; typically implemented with recursion or an explicit stack. | Topological sort, cycle detection, connected components, subtree times. |
DSL | Domain-Specific Language — tailored language. | SQL, Regex, build DSLs. |
EOF | End Of File — no more data to read. | Read returns EOF on file end. |
FASM/MASM/NASM/TASM | Flat Assembler / Microsoft Macro Assembler / Netwide Assembler / Turbo Assembler — popular assemblers for the x86 architecture. | Writing bootloaders or optimizing code with x86 assembly. |
FFI | Foreign Function Interface — mechanism to call functions across language/ABI boundaries. | Rust extern "C" to call C; Python ctypes /cffi bindings. |
FIFO | First In, First Out — queue discipline. | Message queues processing order. |
FP | Functional Programming — pure functions/immutability. | Map/filter/reduce pipelines. |
FSM | Finite State Machine — computational model with a finite number of states and transitions driven by inputs/events. | UI workflows, protocol handlers, and parsers modeled as FSMs. |
GADT | Generalized Algebraic Data Type — ADT whose constructors can refine the result type, enabling more precise typing and safer pattern matches. | Haskell/OCaml GADTs for typed ASTs; matching narrows types. |
GC | Garbage Collection — automatic memory management. | JVM/CLR collectors free unused objects. |
gRPC | High-performance RPC over HTTP/2 with Protobuf. | Define .proto ; generate client/server stubs. |
GUI | Graphical User Interface — visual interaction. | Desktop app windows, buttons. |
I/O | Input/Output — transfer of data to/from a program and external systems or devices. | File I/O, network I/O; blocking vs non‑blocking/async I/O. |
IDE | Integrated Development Environment — all-in-one dev app. | IntelliJ, VS Code (w/ extensions). |
IDL | Interface Definition Language — specification language to describe interfaces and data types for generating cross-language bindings and IPC stubs. | Define COM interfaces in MIDL or CORBA IDL; generate proxies/stubs for RPC. |
IIFE | Immediately Invoked Function Expression. | (function(){ })() in JS. |
JDBC | Java Database Connectivity — DB API. | DriverManager.getConnection(...) . |
JDK | Java Development Kit — Java dev tools. | javac , jar . |
JRE | Java Runtime Environment — run Java apps. | java -jar app.jar . |
JVM | Java Virtual Machine — runs bytecode. | JVM-based languages (Kotlin, Scala). |
LINQ | Language-Integrated Query — a .NET feature that adds native data querying capabilities to languages like C#. | Use LINQ to query collections, databases (via EF), and XML. |
LRU | Least Recently Used — cache eviction policy that discards the least recently accessed items first. | LRU caches/maps in memory-constrained systems. |
LSB | Least Significant Bit — the bit with the lowest positional value in a binary number (2^0); determines odd/even and is affected first by increment. | In 0b1011, the LSB is 1; little‑endian stores LSB byte first. |
LSP | Language Server Protocol — standard JSON-RPC protocol between editors and language servers for code intelligence. | VS Code/Neovim language servers for hover, completion, diagnostics. |
MSB | Most Significant Bit — the bit with the highest positional value; often used as the sign bit in signed integers. | In 0b1011, the MSB is 1; big‑endian stores MSB byte first. |
MST | Minimum Spanning Tree — subset of edges that connects all vertices in a weighted, undirected graph with minimum total weight and no cycles. | Compute MST with Kruskal (sort edges + DSU) or Prim (priority queue). |
NaN | Not a Number — IEEE 754 floating‑point special value representing undefined/invalid results; propagates through computations and is unordered (not equal to any value, including itself). | 0.0/0.0 or sqrt(-1.0) produce NaN; NaN != NaN is true; use isnan() to test. |
NOP | No Operation — instruction or operation that intentionally does nothing; used for timing, alignment, patching, or as a placeholder. | CPU NOP instruction; inserting a no‑op in pipelines or bytecode. |
NPE | Null Pointer Exception — runtime error arising from dereferencing a null reference/pointer in languages with nullable references. | Java NullPointerException , C# NullReferenceException ; avoid with null checks, Option/Optional, or null‑safety features. |
ODBC | Open Database Connectivity — cross-platform C API and driver model for accessing relational databases. | Configure DSNs; apps connect via ODBC drivers to SQL Server/MySQL/Postgres. |
OLE | Object Linking and Embedding — Microsoft technology (built on COM) for embedding and linking documents/objects between applications. | Embed an Excel sheet in a Word doc; OLE automation for Office apps. |
OOM | Out Of Memory — condition where available memory is exhausted and allocations fail. | Linux OOM killer terminates processes; runtime throws OOM error. |
OOP | Object-Oriented Programming — encapsulation/inheritance/polymorphism. | Classes, interfaces, virtual methods. |
ORM | Object-Relational Mapping — map objects to relational tables. | ORM entities and repositories. |
OTP | Open Telecom Platform — the standard library, design principles, and set of tools for building robust, concurrent systems in Erlang/Elixir. | gen_server and supervisor are key OTP behaviours. |
PCRE | Perl Compatible Regular Expressions — regex libraries and syntax compatible with Perl's regex engine (PCRE/PCRE2). | grep -P , nginx, PHP use PCRE/PCRE2 for advanced regex features. |
RAII | Resource Acquisition Is Initialization — lifetime control. | C++ locks released at scope end. |
Regex | Regular Expression — declarative pattern syntax for matching, searching, and transforming strings; available in most languages and tooling with varying feature levels (POSIX, PCRE, etc.). | Use /^foo.*bar$/ to validate inputs; run `rg --ignore-case 'error |
REPL | Read–Eval–Print Loop — interactive shell. | Python/Node REPL. |
RPC | Remote Procedure Call — call functions on a service. | gRPC CreateUser method. |
RPN | Reverse Polish Notation — postfix notation for arithmetic expressions that eliminates parentheses and associates operators with operands directly; naturally evaluated with a stack. | Evaluate 3 4 + 2 * with a stack; HP calculators and some compilers/VMs use RPN internally. |
SDK | Software Development Kit — tools/libs for a platform. | AWS SDK for programmatic access. |
SICP | Structure and Interpretation of Computer Programs — seminal MIT textbook that teaches computer science fundamentals through Scheme, abstraction, and metalinguistic evaluation. | Work through the SICP exercises, building interpreters and analyzers to internalize recursion, higher-order procedures, and data-driven design. |
SUT | System Under Test — the specific component or boundary being exercised by a test, often isolated from collaborators via test doubles. | Unit test drives the SUT (a service class) while stubbing its repository and asserting outputs/interactions. |
TLS | Thread-Local Storage — per-thread storage for data that gives each thread its own instance of a variable. | C/C++ thread_local /__thread , POSIX pthread_key_create ; Rust thread_local! . |
TUI | Text-based User Interface — terminal UI. | htop , ncurses apps. |
UB | Undefined Behaviour — program operations for which the language standard imposes no requirements, allowing compilers to assume they never happen and enabling aggressive optimizations. | C/C++ out‑of‑bounds access, use‑after‑free, signed overflow; can lead to unpredictable results; use sanitizers to detect. |
UTC | Coordinated Universal Time — global time standard. | Timestamps/logs in UTC. |
UWP | Universal Windows Platform — a platform for creating apps that run across Windows devices. | Build a Windows Store app with UWP and XAML. |
VBE | Visual Basic Editor — the integrated development environment for writing and editing VBA code within Microsoft Office. | Press Alt+F11 in Excel to open the VBE. |
VS | Visual Studio — Microsoft's integrated development environment (IDE) for .NET and C++ development on Windows. | Develop, debug, and deploy applications with the Visual Studio IDE. |
WPF | Windows Presentation Foundation — a UI framework for building Windows desktop applications with XAML. | Modern desktop apps with data binding and hardware acceleration. |
WYSIWYG | What You See Is What You Get — direct-manipulation editor. | Rich text editors. |
XAML | Extensible Application Markup Language — a declarative markup language used by Microsoft UI frameworks like WPF and UWP. | Define UI layouts and data bindings in .xaml files. |
Historical {colspan=-3} | ||
RMI | Remote Method Invocation — Java's distributed objects technology enabling method calls on remote JVMs via stubs/skeletons over JRMP (or IIOP for RMI‑IIOP). | Early Java distributed systems; largely supplanted by HTTP/REST, gRPC, and message queues. |
Compilers
Acronym | Meaning | Example |
---|---|---|
ANTLR | ANother Tool for Language Recognition — a popular parser generator for reading, processing, executing, or translating structured text or binary files. | Generate a parser from a grammar file for a custom language. |
AOT | Ahead-Of-Time compilation — compile before runtime. | Angular AOT compiles templates during build. |
AST | Abstract Syntax Tree — structured tree representation of parsed source code used by compilers and tooling. | AST nodes for statements/expressions in parsers/linters. |
BNF | Backus–Naur Form — notation for expressing context‑free grammars used to define programming language syntax. | Language specs define grammar productions in BNF or EBNF. |
CFG | Context‑Free Grammar — formal grammar class used to define programming language syntax; typically expressed in BNF/EBNF and parsed by LL/LR/GLR/PEG parsers. | Write grammar productions; generate parsers with yacc/bison/ANTLR. |
CFG | Control Flow Graph — directed graph of basic blocks and edges representing possible control transfers within a function/program; foundation for data‑flow analysis and many optimizations. | Build CFG to compute dominators/loops; enable DCE, SSA construction, and liveness. |
CIL | Common Intermediate Language — the bytecode language for the .NET runtime (CLR), to which languages like C# and VB.NET compile. | ildasm to inspect the CIL of a .NET assembly; also known as MSIL. |
CSE | Common Subexpression Elimination — remove repeated identical expressions by computing once and reusing the value within a region. | Within a block, compute x+y once and reuse; global variants extend across blocks. |
DCE | Dead Code Elimination — remove code shown by analysis to have no effect on program outputs/side effects, improving size and performance. | Eliminate unused assignments/branches after liveness/constant propagation; -O2 passes in LLVM/GCC. |
DFA | Data Flow Analysis — family of static analyses that compute facts about program variables/paths over a control flow graph using lattice/transfer functions (e.g., reaching definitions, liveness, constant propagation). | Run forward/backward analyses on a CFG; feed results to optimizations like DCE, CSE, and register allocation. |
DFA | Deterministic Finite Automaton — finite-state machine with exactly one transition per symbol for each state; used in lexers/pattern matching. | Tokenizer state machine generated from regular languages. |
DWARF | Debug With Arbitrary Record Format — standardized debugging information format for compiled programs (types, symbols, line tables, call frames) used across platforms. | GCC/Clang emit DWARF in ELF/Mach-O; inspect with readelf --debug-dump or llvm-dwarfdump ; GDB/LLDB consume DWARF. |
EBNF | Extended Backus–Naur Form — BNF with additional operators (repetition, optional, grouping) for more concise grammar specifications. | { } repetition, [ ] optional; used in many language grammars and docs. |
FAM | Flexible Array Member — language/ABI feature where a struct’s last field is a size‑unspecified array used to tail‑allocate variable‑length data; not counted in sizeof and requires custom allocation/copy logic. | In C (C99+): struct S{size_t n; int a[];}; allocate with malloc(sizeof(struct S)+n*sizeof(int)) ; a occupies trailing storage. |
GCC | GNU Compiler Collection — suite of compilers for C/C++/Fortran and more. | gcc /g++ toolchains for building software. |
GL | Graphics Library — SGI's proprietary immediate-mode 3D graphics API for IRIS workstations; precursor to the portable OpenGL standard. | Develop IRIS GL applications on SGI hardware; OpenGL later standardized much of the API for cross-platform use. |
GLSL | OpenGL Shading Language — high-level C-like language for writing programmable shaders targeting OpenGL and Vulkan (via SPIR-V). | Write vertex/fragment/compute shaders compiled by drivers or offline to SPIR-V for Vulkan pipelines. |
GVN | Global Value Numbering — discover semantically equivalent computations (beyond syntactic equality) to eliminate redundancies across the dominator tree. | Treat t=x; z=t+y as x+y ; coalesce values through copies/φ nodes in SSA. |
HLSL | High-Level Shading Language — Microsoft’s shader language for DirectX that compiles to DXIL/DXBC and can be cross-compiled to SPIR-V for Vulkan. | Author shaders in HLSL for Direct3D 11/12; use DXC/FXC or SPIRV-Cross for other runtimes. |
HM | Hindley–Milner — a classical type inference algorithm that automatically deduces the types of expressions in some statically typed languages. | The basis for type inference in ML-family languages and Haskell. |
IR | Intermediate Representation — compiler/transformation-friendly program form between source and machine code. | LLVM IR, SSA-based IRs used for optimization. |
JIT | Just-In-Time compilation — runtime optimization. | HotSpot JIT compiles hot methods. |
LICM | Loop-Invariant Code Motion — hoist computations whose operands don’t change within a loop to preheaders, and sink post‑loop where safe. | Move len(arr) /c*2 out of the loop body to reduce work. |
LLVM | Low Level Virtual Machine — modular compiler toolchain and IR used by many languages. | Clang/LLVM backends, llc , opt , and LLVM IR. |
LTO | Link Time Optimization — whole‑program optimization performed at link time across translation units, typically by linking IR/bitcode and running interprocedural passes. | -flto in Clang/GCC; enables cross‑TU inlining, DCE, devirtualization, ICF/WPO. |
MLIR | Multi-Level Intermediate Representation — an extensible compiler infrastructure in LLVM that models programs across dialects to enable reusable transformations for domain-specific compilers and accelerators. | Use MLIR dialects (Linalg, GPU, Tensor) to lower ML programs toward LLVM IR or hardware-specific codegen. |
NFA | Nondeterministic Finite Automaton — automaton model for regular languages allowing ε‑transitions and multiple possible next states; typically converted to an equivalent DFA for efficient matching. | Build NFA from regex via Thompson's construction; convert to DFA by subset construction for lexers. |
NRVO | Named Return Value Optimization — compiler optimization that elides copies/moves by constructing a named local return object directly in the caller’s storage. | T f(){ T x; return x; } constructs x in the caller (C++); differs from RVO on unnamed temporaries. |
OBJ | Object File — intermediate binary produced by compilers/assemblers containing machine code, data, relocation records, and symbol tables to be linked into executables or libraries. | Build foo.o /foo.obj then link with ld /link.exe ; inspect with objdump , otool , or llvm-objdump . |
PEG | Parsing Expression Grammar — recognition‑based grammar formalism with ordered (prioritized) choice and unlimited lookahead; often parsed via packrat parsing with memoization for linear time. | Define a PEG for a language and parse with PEG.js/pest/PEGTL; use ordered choice instead of ambiguous CFGs. |
PRE | Partial Redundancy Elimination — inserts computations to make partially redundant expressions fully redundant, then removes duplicates (often via Lazy Code Motion/SSA-PRE). | If a+b happens on some paths and later unconditionally, place it optimally so all uses share one computed value. |
RTTI | Run-Time Type Information — runtime facility to query an object's dynamic type and perform safe downcasts/instance checks in languages with polymorphism. | In C++, use dynamic_cast<Base*> and typeid ; in Java/C#, use instanceof /is and reflection APIs. |
RVO | Return Value Optimization — compiler optimization that elides copies/moves by constructing a returned temporary directly in the caller’s storage. | T f(){ return T(); } constructs the T in the caller; guaranteed in C++17 (copy elision rules). |
SPIR-V | Standard Portable Intermediate Representation — Khronos binary intermediate language for GPU compute/graphics shaders used by Vulkan, OpenCL, and WebGPU toolchains. | Compile GLSL/HLSL to SPIR-V for Vulkan pipelines; emit SPIR-V from MLIR/LLVM for compute shaders. |
SSA | Static Single Assignment — IR form where each variable is assigned exactly once, using φ (phi) functions at merge points; simplifies data‑flow analysis and optimization. | Convert to SSA to enable efficient DCE, copy propagation, and value numbering; SSA in LLVM IR. |
TCO | Tail Call Optimization — reuse the current stack frame for a tail call to avoid stack growth and enable efficient tail recursion. | Compilers transform tail-recursive functions into loops; mandated in some languages (Scheme), optional in others. |
UFCS | Uniform Function Call Syntax — language feature that allows calling free/extension functions with method-call syntax by implicitly passing the receiver as the first argument. | D/Scala/Rust desugar x.f(y) to f(x, y) ; extension methods in C#/Kotlin/Swift. |
Operating Systems
Acronym | Meaning | Example |
---|---|---|
ABI | Application Binary Interface — low-level contract governing calling conventions, data layout, and linkage between compiled code and the OS/runtime. | x86‑64 System V ABI, Windows x64 ABI; stable FFI boundaries. |
APK | Android Package Kit — archived bundle (ZIP with AndroidManifest.xml , resources, and compiled bytecode) used to distribute and install Android apps. | Build app-release.apk , sign it, and install with adb install or upload to Play. |
ASLR | Address Space Layout Randomization — security technique that randomizes process address spaces (stack/heap/ASLR-enabled libs) to make memory corruption exploits less reliable. | cat /proc/sys/kernel/randomize_va_space ; Windows system-wide ASLR. |
BAT | Batch file — Windows Command Prompt script file executed by cmd.exe ; commonly .bat or .cmd . | Automation scripts using built-ins like echo , set , if , for . |
BSD | Berkeley Software Distribution — family of UNIX-like operating systems descended from research UNIX at UC Berkeley, known for its permissive license. | FreeBSD, OpenBSD, NetBSD used in servers and embedded systems. |
BSS | Block Started by Symbol — segment for zero‑initialized or uninitialized static/global data that occupies memory at load/runtime but takes no space in the object file beyond metadata (size). | C static int buf[4096]; goes to .bss ; reduces binary size versus storing zeros. |
CMD | Windows Command Prompt — command-line interpreter (cmd.exe ) for Windows providing batch scripting (.bat/.cmd) and built-in shell commands. | Run cmd.exe ; use dir , copy , set and %PATH% ; legacy scripts for automation. |
COW | Copy-On-Write — share pages or objects until a write occurs, then copy to preserve isolation; reduces memory/IO and enables efficient forks/snapshots. | fork() shares pages COW; VM snapshots; filesystem COW in ZFS/Btrfs. |
DLL | Dynamic-Link Library — shared library format on Windows loaded at runtime into a process address space. | foo.dll loaded via LoadLibrary; shared code/plugins. |
DPC | Deferred Procedure Call — mechanism (notably in Windows) to queue a function for execution at a lower IRQL than the ISR that scheduled it, enabling faster interrupt handling. | A network driver's ISR queues a DPC to process incoming packets. |
DSO | Dynamic Shared Object — generic term for a shared library (.so , .dll , .dylib ) loaded at runtime and linked into a process's address space. | Use dlopen to load a DSO and dlsym to resolve symbols from it. |
DYLIB | Dynamic Library — macOS shared library format loaded by the dynamic linker. | libfoo.dylib via dyld; install_name_tool /rpaths for relocation. |
ELF | Executable and Linkable Format — standard binary format for executables, object files, and shared libraries on Unix-like systems. | Linux binaries with sections/segments; inspect with readelf /objdump . |
EXE | Executable file — Windows program file using the Portable Executable (PE) format for executables and DLLs. | Launch .exe apps; inspect PE headers with dumpbin /objdump . |
FS | File System — on-disk or logical structure and set of rules the OS uses to organize, store, and retrieve files/directories, including metadata and allocation. | ext4, NTFS, APFS, ZFS; mount/unmount volumes; permissions and journaling. |
FUSE | Filesystem in Userspace — kernel interface to implement filesystems in user space processes. | Mount sshfs /rclone via FUSE; custom FS without kernel modules. |
GDT | Global Descriptor Table — a core data structure in the x86 architecture that defines memory segments for the CPU. | Kernel setup of GDT for code/data segments in protected mode. |
GNOME | GNU Network Object Model Environment — free, open‑source desktop environment for UNIX-like systems, part of the GNU Project. | Default desktop on many Linux distributions; GNOME Shell with Wayland/X11. |
HAL | Hardware Abstraction Layer — OS layer that hides hardware specifics behind a uniform API so drivers/system code can run across platforms. | Windows HAL; OS kernels providing common driver interfaces across architectures. |
IDT | Interrupt Descriptor Table — x86 data structure that associates interrupt vectors with the addresses of their interrupt service routines (ISRs). | OS populates the IDT to handle hardware interrupts and exceptions. |
IFS | Installable File System — an API in an operating system that allows new file systems to be loaded dynamically. | Windows IFS for NTFS, FAT32, and third-party file systems; OS/2's IFS. |
IPC | Inter-Process Communication — exchange/coordinate between processes. | Pipes, sockets, shared memory, signals. |
ISR | Interrupt Service Routine — function invoked by the OS in response to an interrupt to handle the event and acknowledge the controller. | Keyboard ISR on IRQ1 reads scancode; timer ISR updates ticks and EOIs the APIC. |
KDE | K Desktop Environment (now the KDE community and Plasma desktop) — free, open‑source desktop environment and software suite for UNIX-like systems. | KDE Plasma on Linux/BSD; highly configurable desktop with KWin and Qt apps. |
L4 | L4 microkernel family — influential second-generation microkernel design emphasizing minimality, high performance, and user-space servers. | seL4 (verified secure); Fiasco.OC; used in secure embedded systems and virtualization. |
Mach-O | Mach Object — executable/object file format used by macOS/iOS for binaries and libraries. | Inspect with otool /lldb ; libfoo.dylib and foo.app/Contents/MacOS/foo . |
MSI | Microsoft Installer — an installer package file format and API for Windows. | .msi packages for installing software on Windows. |
NDIS | Network Driver Interface Specification — a Microsoft API for network card drivers, forming a layer between the protocol stack and the hardware driver. | Writing an NDIS miniport driver; the standard for Windows network drivers. |
NTFS | New Technology File System — Windows journaling filesystem with ACLs, alternate data streams, compression, and quotas. | Format a Windows system volume as NTFS; set ACLs with icacls. |
OS | Operating System — system software that manages hardware resources and provides common services for programs. | Linux, Windows, macOS; kernel, drivers, processes, filesystems. |
PCB | Process Control Block — kernel data structure containing the state of a process (registers, PID, scheduling info, memory maps). | The OS saves/restores the PCB during a context switch. |
PE | Portable Executable — Windows binary format for executables, DLLs, and object files. | Inspect with dumpbin /objdump ; sections, import/export tables. |
PID | Process Identifier — numeric ID assigned by the kernel to a process. | pid=1 init/systemd; ps -o pid,comm . |
POSIX | Portable OS Interface — Unix-like standard APIs. | fork , exec , pthread APIs. |
PTY | Pseudo Terminal — virtual terminal pair (master/slave) used by terminal emulators and remote sessions to emulate a real TTY. | /dev/pts/* , ssh -t , forkpty , tmux . |
QNX | QNX Neutrino RTOS — commercial Unix-like real-time operating system with a microkernel architecture, widely used in embedded systems. | Automotive infotainment (BlackBerry IVY), industrial controllers, medical devices. |
RCU | Read-Copy-Update — synchronization mechanism allowing lock-free reads by deferring updates/reclamation until all readers in a grace period complete. | Linux kernel uses RCU for highly concurrent data structures in networking/VFS. |
RPM | RPM Package Manager (originally Red Hat Package Manager) — a package management system used by many Linux distributions. | rpm -i package.rpm ; yum /dnf use RPM packages. |
RTOS | Real-Time Operating System — OS designed for deterministic response and bounded latency, with priority-based scheduling and real-time primitives. | FreeRTOS, Zephyr, VxWorks on microcontrollers/embedded systems; hard vs soft real-time. |
SO | Shared Object — Unix/Linux shared library format loaded by the dynamic linker. | libfoo.so via ld.so/dlopen ; sonames and rpaths. |
SUS | Single UNIX Specification — standard defining UNIX interfaces and behavior maintained by The Open Group, ensuring POSIX compliance and application portability. | SUS/POSIX APIs (unistd.h , signals, threads); conformant systems like AIX, HP-UX, macOS. |
TCB | Thread Control Block — kernel data structure that stores the state of a thread, including its registers, stack pointer, and scheduling information. | Analogous to a PCB but for a thread; managed by the scheduler. |
TID | Thread Identifier — numeric ID for a thread (often equals PID for single-threaded processes; Linux has per-thread TIDs). | gettid() on Linux; pthread_self() maps to a TID. |
TPF | Transaction Processing Facility — IBM's high-performance successor to ACP, optimized for nonstop, large-scale transaction processing on mainframes in aviation, finance, and hospitality. | Airlines, card networks, and hotels run IBM ZTPF/TPF on IBM Z to process reservations and payments at extreme throughput. |
TTY | Teletype/Terminal — character device for text I/O; terminal sessions. | /dev/tty , PTY in shells. |
Legacy | ||
AIX | IBM's UNIX (Advanced Interactive eXecutive) for POWER systems, featuring LPARs, SMIT, JFS2, and enterprise tooling. | IBM Power Systems running AIX on POWER9/POWER10; manage with SMIT/VIOS. |
COM | DOS executable — simple flat binary loaded at offset 0x100 with ~64KB segment limit and no header. | Classic .COM utilities/programs on MS‑DOS/PC‑DOS; tiny loaders/stubs. |
IVT | Interrupt Vector Table — x86 real‑mode table at 0x0000:0000 with 256 interrupt pointers; superseded by IDT in protected/long mode. | Bootloaders may patch IVT entries before switching modes. |
JCL | Job Control Language — scripting language used on IBM mainframes to control batch job execution. | //SYSIN DD * statements in a JCL deck to submit a batch job. |
MCP | Master Control Program — Unisys mainframe OS in the Burroughs large‑systems line, featuring a stack machine architecture and strong language support; still in use but niche. | Unisys ClearPath MCP systems (Burroughs B5000 lineage) running enterprise workloads. |
NT | New Technology — Microsoft’s NT family/architecture underlying Windows NT and its successors (2000/XP/Vista/7/8/10/11), featuring a hybrid kernel, HAL, NTFS, and Win32/NT native subsystems. | Windows NT lineage; ver shows NT versioning; services/session model and security based on NT architecture. |
UAC | User Account Control — Windows elevation and consent mechanism to limit silent privilege escalation. | Admin tasks prompt for consent; split‑token admin accounts. |
UDS | Unix Domain Socket — IPC mechanism using socket endpoints on the local host with filesystem pathnames or abstract namespace. | /var/run/docker.sock ; faster than TCP on localhost. |
VDSO | virtual Dynamic Shared Object — small shared library exposed by the kernel and mapped into user processes to provide fast, syscall-free access to certain kernel routines. | gettimeofday() calls on Linux are often implemented via the vDSO to avoid context switches. |
VFAT | Virtual FAT — an extension to the FAT filesystem that introduced long filename support in Windows 95. | Enabled filenames longer than the 8.3 DOS convention. |
VFS | Virtual File System — OS abstraction layer that provides a uniform API over different filesystems and devices. | Linux VFS layer exposes common inode/dentry APIs across ext4, XFS, NFS, FUSE. |
VM | Virtual Memory — OS abstraction that gives processes isolated address spaces mapped to physical memory via paging/segmentation. | Per‑process address spaces, page tables, demand paging, copy‑on‑write. |
X11 | X Window System (Version 11) — network‑transparent windowing system and protocol for bitmap displays on UNIX‑like systems. | Xorg/XWayland on Linux; XQuartz on macOS; ssh -X X11 forwarding. |
z/OS | IBM's mainframe operating system for IBM Z, successor to OS/390 and MVS; provides JES2/3, RACF security, JCL batch, and UNIX System Services (POSIX environment). | Enterprise workloads on IBM Z mainframes; partitioned datasets, CICS/IMS, and USS shells. |
ZFS | Zettabyte File System — advanced filesystem/volume manager with snapshots, checksums, compression, and COW semantics. | Create ZFS datasets/pools; instant snapshots/zfs send replication. |
Historical | ||
A/UX | Apple UNIX — Apple's early implementation of Unix for their 68k-based Macintosh computers, featuring a Mac-like GUI. | An early attempt to merge the Mac GUI with a POSIX-compliant Unix kernel. |
ACP | Airline Control Program — IBM's specialized high-throughput transaction processing operating system for System/360 and System/370, engineered for airline reservations and other real-time industries; predecessor to TPF. | Run on IBM mainframes to power reservation systems; later evolved into the Transaction Processing Facility (TPF). |
CDE | Common Desktop Environment — classic UNIX desktop environment based on Motif and the X Window System; widely used on commercial UNIX workstations in the 1990s. | HP‑UX, Solaris, AIX shipped CDE as the default desktop; superseded by GNOME/KDE. |
COFF | Common Object File Format — early, influential format for executables and object files on Unix-like systems. | Predecessor to ELF and PE; used in early System V. |
CP/CMS | Control Program / Cambridge Monitor System — IBM's experimental virtualization-focused time-sharing system for the System/360 Model 67, pairing a hypervisor (CP) with per-user CMS interactive environments. | Demonstrated full virtual machines hosting guest OSes; evolved into VM/370 and laid the groundwork for modern IBM mainframe virtualization. |
CP/M | Control Program for Microcomputers — early microcomputer OS preceding MS‑DOS. | 1970s/80s 8‑bit systems running CP/M. |
CTSS | Compatible Time-Sharing System — pioneering time-sharing OS developed at MIT for the IBM 7090/7094; introduced concepts like password logins and interactive command shells; precursor to MULTICS. | MIT Project MAC on IBM 7094; early 1960s interactive computing. |
DG/UX | Data General's UNIX for AViiON servers/workstations; SVR4-based, multi-processor support; discontinued. | DG AViiON systems running DG/UX; enterprise UNIX of the 1990s. |
DOS | Disk Operating System — family of disk‑based OSes. | MS‑DOS, PC‑DOS, DR‑DOS. |
DTSS | Dartmouth Time-Sharing System — early time-sharing operating system co-developed with the Dartmouth BASIC language to provide interactive computing access to students and faculty. | Students logged into DTSS terminals to run BASIC programs; influenced later educational and commercial time-sharing services. |
EMS | Expanded Memory Specification — paged memory technique (bank switching) to access >1MB of RAM on 8086/286 PCs in real mode via a 64KB page frame in the UMA. | Lotus/Intel/Microsoft (LIM) EMS; configure with EMM386.EXE for DOS games/apps. |
GCOS | General Comprehensive Operating System — Honeywell/Bull mainframe OS originally launched as GECOS (General Electric Comprehensive Operating Supervisor), known for robust batch and transaction processing. | Unix /etc/passwd "gecos" field traces back to GCOS interoperability; enterprises still run GCOS on Bull mainframes. |
GEM | Graphics Environment Manager — a WIMP-style GUI from Digital Research, used on the Atari ST and Amstrad PCs. | The GEM desktop environment; competitor to early Mac OS and Windows. |
GEOS | Graphic Environment Operating System — a GUI-based operating system for 8-bit home computers and later for PCs. | Popular on the Commodore 64; PC/GEOS was an alternative to early Windows. |
HMA | High Memory Area — the first ~64KB of extended memory, made accessible in real mode on 286+ CPUs by manipulating the A20 line. | Load DOS into the HMA (DOS=HIGH ) to free up conventional memory. |
IRIX | SGI's UNIX for MIPS workstations/servers; renowned for graphics and the original home of XFS; discontinued. | SGI Octane/Onyx systems running IRIX; MIPSpro toolchain; legacy SGI graphics stacks. |
ITS | Incompatible Timesharing System — MIT's hacker-centric time-sharing OS for the PDP-6 and PDP-10 that introduced extensible systems, open access, and influential developer culture. | Hackers ran ITS on MIT AI Lab PDP-10s; today enthusiasts explore it via SIMH/KA/KI/KL emulators. |
LM | LAN Manager — a network operating system (NOS) developed by Microsoft and 3Com, a predecessor to Windows NT Server. | Competed with Novell NetWare; ran on OS/2. |
MFT | Multiprogramming with a Fixed number of Tasks — an early configuration of IBM's OS/360 that managed a fixed number of concurrent jobs in static memory partitions. | One of the primary OS/360 options alongside MVT (Variable number of Tasks). |
MP/M | Multiprogramming Monitor for Microprocessors — a multi-user version of the CP/M operating system. | Early 8-bit multi-user business systems; predecessor to Concurrent CP/M. |
MULTICS | Multiplexed Information and Computing Service — ambitious time-sharing OS jointly developed by MIT, Bell Labs, and GE, pioneering concepts like hierarchical file systems, ring-based security, and dynamic linking. | Ran on GE-645/Honeywell machines; inspired UNIX and modern OS designs; notable for shared memory segments and user ring protection. |
MULTICS | Multiplexed Information and Computing Service — influential time‑sharing OS from MIT/GE/Bell Labs that inspired many UNIX concepts. | 1960s/70s mainframes; security and modular design influenced Unix. |
MVS | Multiple Virtual Storage — mainstream IBM mainframe OS from the System/370 era onward, providing robust batch and transaction processing; evolved into OS/390 and z/OS. | Run CICS/IMS transactions; submit JCL batch jobs; manage DASD with VSAM. |
MVT | Multiprogramming with a Variable number of Tasks — a configuration of IBM's OS/360 that was a precursor to MVS, allowing for a dynamic number of concurrent jobs. | One of the primary OS/360 options alongside MFT (Fixed number of Tasks). |
NLM | NetWare Loadable Module — a server module (driver, application, or utility) that could be dynamically loaded and unloaded in the Novell NetWare operating system. | .NLM files for drivers and server applications on a NetWare server. |
OS/2 | IBM/Microsoft then IBM OS succeeding DOS. | OS/2 Warp on 1990s PCs. |
OS/360 | Operating System/360 — IBM's influential mainframe OS for the System/360, introducing concepts like JCL, partitioned datasets, and a family of compatible systems. | Run batch jobs with JCL; manage datasets on DASD; MFT/MVT variants. |
OS/370 | Operating System/370 — successor to OS/360 for System/370 mainframes, introducing virtual memory (SVS/MVS). | MVS (Multiple Virtual Storage) became the mainstream OS/370 version. |
OS/390 | Successor to MVS/ESA, integrating UNIX services (USS) and other modern features into the core mainframe OS; predecessor to z/OS. | Run UNIX and batch workloads on the same system; prepare for Y2K. |
OSF/1 | Open Software Foundation's UNIX, later Digital UNIX/Tru64; SVR4-based with Mach kernel components and advanced features. | DEC Alpha systems running Digital UNIX; TruCluster high-availability. |
PLATO | Programmed Logic for Automatic Teaching Operations — pioneering computer-based education system with touch-enabled terminals, graphical courseware, and early online community features (forums, chat). | University of Illinois' PLATO IV terminals delivered interactive lessons and multiplayer games; influenced modern e-learning and social computing. |
RISC OS | Acorn's desktop operating system for ARM-based Archimedes and Risc PC machines, featuring a WIMP interface and cooperative multitasking. | Run on Acorn Archimedes/Risc PC systems; modern builds run RISC OS Open on Raspberry Pi. |
RSTS | Resource Sharing Time-Sharing — DEC's multi-user PDP-11 operating system that merged RT-11 friendliness with RSX services for schools and business computing. | Boot RSTS/E on a PDP-11 or under SIMH to run BASIC, COBOL, and timeshared workloads. |
RSX | Real-Time System Executive — DEC's multi-user, multitasking real-time operating system family for PDP-11 minicomputers. | Run RSX-11M/RSX-11M-Plus on PDP-11 hardware or via SIMH for industrial control and retrocomputing. |
RT-11 | Real-Time 11 — DEC's single-user real-time operating system for PDP-11 minicomputers, optimized for lab automation and embedded control. | Load RT-11 from floppy/disk on PDP-11 hardware or run under SIMH for vintage development. |
SABRE | Semi-Automated Business Research Environment — American Airlines/IBM's pioneering real-time airline reservation system derived from SAGE concepts. | Early 1960s SABRE mainframes booked flights via networked agent terminals; evolved into modern Sabre GDS platforms. |
SAGE | Semi-Automatic Ground Environment — Cold War-era air defense system combining massive AN/FSQ-7 computers, radar feeds, and real-time command software to track aircraft and coordinate intercepts. | 1950s USAF direction centers ran SAGE consoles and radar plots; preserved today via simulations and museum restorations. |
SVR4 | System V Release 4 — AT&T/Sun UNIX unifying System V, BSD, and Xenix features; foundation for many 1990s commercial UNIXes. | Solaris 2.x and UnixWare derive from SVR4 with STREAMS networking and SVR4 package tools. |
TENEX | TEN Executive — BBN's influential PDP-10 time-sharing operating system introducing demand paging, virtual memory, and ARPANET innovations that fed directly into DEC's TOPS-20. | Early ARPANET nodes ran TENEX; features like the Exec shell, JSYS calls, and paging hardware shaped later TOPS-20 and other networked OSes. |
TOPS | Total Operating System — DEC's time-sharing operating systems for the PDP-10/DECsystem-10 (TOPS-10) and DECsystem-20 (TOPS-20), foundational during the ARPANET era. | Explore TOPS-10/TOPS-20 on emulated DECsystem hardware; develop with ITS-style monitors and early networking tools. |
TSR | Terminate and Stay Resident — DOS resident utility/program. | Keyboard macros/clock TSRs in MS-DOS. |
TSS/360 | Time Sharing System/360 — IBM's ambitious but troubled time-sharing operating system for the System/360 Model 67, introducing virtual memory and interactive access; lessons informed later VM/370. | Provided remote terminal access on S/360-67 with DAT hardware; performance/complexity issues led IBM to focus on successor systems. |
UMA | Upper Memory Area — the memory block between 640KB and 1MB on PCs, used for system BIOS, option ROMs, and video memory; free portions (UMBs) could map drivers/TSRs. | Load drivers high with DEVICEHIGH in CONFIG.SYS to free conventional memory. |
VAXELN | VAX Embedded Local Network — DEC's real-time operating system for VAX systems that provided networked, event-driven control applications with VMS tooling. | Build VAXELN images on VMS hosts and deploy to VAX hardware or emulators for industrial automation use cases. |
VM/370 | Virtual Machine/370 — IBM's first official release of the VM hypervisor for the System/370, a landmark in virtualization. | Predecessor to later VM/ESA and z/VM systems. |
VM/CMS | Virtual Machine / Conversational Monitor System — the combination of the VM hypervisor and its single-user interactive CMS operating system. | The primary user experience on IBM mainframe time-sharing systems. |
VMS | Virtual Memory System — DEC's operating system for VAX (later Alpha/Itanium as OpenVMS), featuring robust clustering and security. | VAX/VMS in enterprises; OpenVMS clusters with RMS/DCL. |
WAITS | Stanford's timesharing system — derived from SAIL's modifications to DEC's TOPS-10 for PDP-10s, adding advanced editing, graphics, and music tooling that influenced interactive computing. | Hosted SAIL's AI research tools, graphical displays, and early computer music systems; many WAITS ideas migrated back into TOPS-10/TOPS-20 ecosystems. |
WfW | Windows for Workgroups — an early version of Microsoft Windows that integrated peer-to-peer networking directly into the OS. | Windows 3.11 for Workgroups with File and Print Sharing. |
XMS | Extended Memory Specification — standard for DOS programs to access extended memory (>1MB) on 286+ CPUs via a driver (HIMEM.SYS) and A20 gate control. | Load DOS high (DOS=HIGH ); use XMS for RAM disks and apps needing large buffers. |
Document Markup
Acronym | Meaning | Example |
---|---|---|
LaTeX | Document preparation system built on TeX that provides high‑level markup for typesetting complex documents (sections, figures, bibliographies) with excellent math support. | Write papers/books with LaTeX classes/packages; pdflatex /xelatex build pipelines. |
MD | Markdown — lightweight plain‑text markup language for formatting documents with simple syntax for headings, lists, emphasis, links, and code. | README.md , GitHub Flavored Markdown; code fences and tables in docs/blogs. |
RST | reStructuredText — plaintext markup language used in the Python ecosystem and Sphinx documentation generator; emphasizes readable source and structured directives. | Sphinx .rst docs with directives/roles; PyPI/ReadTheDocs project documentation. |
TeX | Low‑level typesetting system designed by Donald Knuth providing precise control over layout and mathematics; foundation for LaTeX and many formats. | Typeset math-heavy documents; plain TeX macros; outputs DVI/PDF via engines like pdfTeX/XeTeX/LuaTeX. |
XML | Extensible Markup Language — verbose structured data. | XML configs, SOAP payloads. |
XSLT | Extensible Stylesheet Language Transformations — declarative language for transforming XML documents using template rules, XPath selection, and functions. | Transform DocBook/XML to HTML/PDF with Saxon/Xalan; XSLT 1.0/2.0/3.0. |
Legacy | ||
DTD | Document Type Definition — schema language defining the legal structure/elements/attributes of SGML/XML documents. | Validate XML with a DTD; <!DOCTYPE ...> declarations; legacy vs XML Schema/Relax NG. |
XSD | XML Schema Definition — the W3C standard for defining the structure and data types of XML documents; the powerful successor to DTD. | Validate XML against an .xsd schema; generate code from schemas. |
Historical | ||
SGML | Standard Generalized Markup Language — meta-language for defining markup languages; foundation for HTML/XML; rarely used directly today. | SGML-based HTML 2.0/3.2 era; modern stacks use XML/HTML5 instead. |
File Formats
Acronym | Meaning | Example |
---|---|---|
AAC | Advanced Audio Coding — a lossy audio compression format that is the successor to MP3, offering better quality at similar bitrates. | Standard audio format for YouTube, Apple devices, and digital video broadcasting. |
CAB | Cabinet archive — Microsoft compressed archive format that supports embedded digital signatures and is commonly used to bundle Windows drivers, updates, and setup payloads. | Windows Update distributions and driver packages ship .cab files; expand or DISM extracts them. |
CHM | Compiled HTML Help — Microsoft compressed archive format packaging HTML, images, and navigation for offline help files, typically viewed via the WinHelp system. | Windows applications shipped .chm manuals; hh.exe opens them; security hardening blocks untrusted CHMs. |
DVI | Device Independent file format — TeX's output format describing pages and typeset content in a device‑agnostic way, later converted to PostScript/PDF or displayed via drivers. | Generate .dvi from TeX; view/convert with dvips , dvipdfmx , or viewers like xdvi. |
EPUB | Electronic Publication — a popular open standard for e-books, using web technologies like HTML, CSS, and SVG. | Read .epub files on an e-reader or with a software viewer. |
ICO | Icon file format — container for one or more images in various sizes/color depths, used for favicons and application icons. | favicon.ico in the web root; Windows .exe icon resources. |
INF | Setup Information file — plain-text configuration scripts that drive Windows installation and configuration of drivers, services, and components. | Windows driver packages ship .inf files consumed by SetupAPI; pnputil adds or stages them. |
INI | Initialization file — simple key/value configuration format organized into sections for Windows applications and many cross-platform tools. | .ini files under %WINDIR% or alongside apps; parsed by GetPrivateProfileString /config libraries. |
MSI | Microsoft Installer package — database-backed installation package format used by Windows Installer to deploy applications, updates, and patches. | Enterprise software ships .msi packages; msiexec installs/uninstalls with logging and transforms. |
OTF | OpenType Font — cross-platform font format that can contain PostScript or TrueType outlines and supports advanced typographic features. | .otf fonts for professional typography; supersedes PostScript Type 1. |
PNG | Portable Network Graphics — lossless raster image format with DEFLATE compression, alpha transparency, and gamma/metadata support. | .png UI assets/screenshots; better compression than BMP; supports transparency. |
PS | PostScript — page description language and programming language used primarily in desktop publishing and printing workflows. | Generate vector/print-ready .ps files; printers interpret PostScript directly; PDF evolved from it. |
SVG | Scalable Vector Graphics — XML-based vector image format for resolution-independent graphics. | Inline icons/diagrams in HTML; CSS/SMIL animations. |
TOML | Tom's Obvious, Minimal Language — minimal configuration format with clear semantics. | pyproject.toml , Cargo.toml tool configs. |
TTF | TrueType Font — outline font format using quadratic Bézier curves; widely supported across operating systems and browsers. | .ttf fonts for desktop/web (often inside .ttc collections or wrapped as WOFF/WOFF2 for the web). |
WOFF | Web Open Font Format — compressed container format for web fonts (TrueType/OpenType), enabling faster delivery; WOFF2 offers improved compression. | Serve .woff2 with a .woff fallback for modern web typography. |
YAML | Human-friendly serialization format. | docker-compose.yml files. |
Legacy | ||
BMP | Bitmap Image File — raster image format (Device‑Independent Bitmap) storing pixel data with optional RLE compression. | .bmp screenshots/icons; large files compared to PNG/JPEG. |
GIF | Graphics Interchange Format — legacy lossless raster image format limited to 256 colors, best known for supporting simple animations. | Animated memes; superseded by PNG for static images and APNG/video for complex animations. |
MP3 | MPEG-1 Audio Layer III — a popular lossy audio compression format that revolutionized digital music. | .mp3 files for music; superseded by AAC but still widely used. |
RTF | Rich Text Format — plain-text document format with markup (control words and groups) for character/paragraph styling; widely supported across editors. | Save/export .rtf from word processors to interchange formatted text. |
Data Encodings
Acronym | Meaning | Example |
---|---|---|
ASCII | American Standard Code for Information Interchange — 7‑bit character encoding defining codes 0–127; subset of UTF‑8. | Plain ASCII text files; printable characters and control codes. |
BOM | Byte Order Mark — optional Unicode signature at the start of a text stream indicating endianness/encoding (UTF‑8/UTF‑16/UTF‑32). | Avoid UTF‑8 BOM in Unix scripts; UTF‑16 LE files start with FE FF. |
CRLF | Carriage Return + Line Feed — sequence \r\n used by Windows and many network protocols as a line terminator. | HTTP headers and CSV on Windows use CRLF line endings. |
DER | Distinguished Encoding Rules — binary ASN.1 encoding used for certificates/keys. | .cer/.der X.509 certs; binary form of ASN.1 structures. |
EBCDIC | Extended Binary Coded Decimal Interchange Code — 8‑bit character encoding used primarily on IBM mainframes; incompatible with ASCII. | Converting EBCDIC files to ASCII/UTF‑8 when integrating with mainframe systems. |
GUID | Globally Unique Identifier — Microsoft’s term for UUID. | {3F25...C3301} COM-style format. |
LF | Line Feed — newline control character (0x0A) used by Unix/Linux/macOS to terminate lines. | \n in text files; contrast with CR (0x0D) and CRLF (\r\n ). |
MIME | Multipurpose Internet Mail Extensions — standardized media types and encoding for content on the internet. | Content-Type: application/json ; multipart/form-data with boundaries. |
PEM | Privacy-Enhanced Mail — Base64 (PEM) encoding with header/footer lines for certs/keys. | -----BEGIN CERTIFICATE----- blocks; .pem/.crt/.key files. |
UCS | Universal Character Set — ISO/IEC 10646 standard defining the full repertoire of Unicode code points; Unicode is kept synchronized with UCS. | UCS-2/UCS-4 historical encodings map to UTF‑16/UTF‑32; code points vs encodings distinction. |
UTF | Unicode Transformation Format — encodings of Unicode code points (e.g., UTF‑8/UTF‑16/UTF‑32). | UTF‑8 is the dominant encoding on the web and in APIs. |
UUID | Universally Unique Identifier — 128-bit unique ID. | UUID v4 random, v5 namespace. |
Legacy | ||
BCD | Binary-Coded Decimal — encoding that represents each decimal digit with its own binary nibble (4 bits), enabling precise decimal arithmetic. | Packed BCD in financial systems; CPU decimal adjust instructions (DAA/DAS). |
MBCS | Multi-Byte Character Set — legacy variable-length encodings that use one or more bytes per character (often DBCS for CJK) prior to widespread Unicode adoption. | Windows "ANSI" code pages (Shift_JIS, EUC‑JP); prefer UTF‑8 today. |
Historical | ||
CR | Carriage Return — control character (0x0D) historically used to move the print head to column 0; used by classic Mac OS as line terminator. | \r in classic Mac text files; pairs with LF in CRLF on Windows. |
Data Formats (Interchange)
Acronym | Meaning | Example |
---|---|---|
BSON | Binary JSON — binary serialization format with typed fields and efficient encoding designed for fast traversal and in-place updates. | MongoDB wire/storage format; supports types like ObjectId, Date, binary; drivers encode/decode BSON. |
CBOR | Concise Binary Object Representation — compact, schema-optional binary data format designed for small code and message size (RFC 8949). | IoT/API payloads with maps/arrays; COSE for CBOR Object Signing and Encryption; diagnostic notation for debugging. |
CSV | Comma-Separated Values — plain text tabular format. | users.csv exports/imports. |
HDF5 | Hierarchical Data Format version 5 — portable file format and library for storing large, complex, heterogeneous scientific data with groups/datasets and rich metadata. | Store arrays/tables/images with chunking/compression; used in scientific computing and ML datasets. |
JSON | JavaScript Object Notation — data format. | { "id": 1 } payloads. |
JSON-LD | JSON for Linking Data — JSON‑based serialization for Linked Data/RDF that uses @context to map terms to IRIs and add semantics to JSON documents. | Embed schema.org with <script type="application/ld+json"> on web pages; exchange RDF graphs in JSON for knowledge graphs/APIs. |
JSONL | JSON Lines — newline‑delimited JSON records for streaming/append‑friendly logs and datasets (aka NDJSON). | One JSON object per line; easy to process with line‑oriented tools. |
netCDF | Network Common Data Form — self‑describing, portable data formats and libraries for array‑oriented scientific data; supports classic (CDF), 64‑bit offset, and netCDF‑4/HDF5. | Earth science datasets (grids/time series); interoperable with many scientific tools. |
ORC | Optimized Row Columnar — columnar storage format optimized for analytics with predicate pushdown, compression, and statistics. | Store big data tables in ORC on Hadoop/Spark; efficient scans and compression. |
OWL | Web Ontology Language — a family of knowledge representation languages for authoring ontologies, based on RDF and standardized by the W3C. | Define classes, properties, and relationships for a domain in an ontology. |
RDF | Resource Description Framework — W3C model for describing and linking data using triples (subject–predicate–object), often serialized as Turtle/RDF/XML/JSON‑LD. | Knowledge graphs, linked data; schema.org markup via JSON‑LD. |
RDFS | RDF Schema — a vocabulary for defining classes and properties for RDF data, providing a basic ontology framework. | rdfs:Class , rdfs:subClassOf , rdfs:domain , rdfs:range . |
SKOS | Simple Knowledge Organization System — a W3C standard for representing knowledge organization systems like thesauruses and taxonomies. | Define concepts with skos:Concept and relationships like skos:broader . |
SPARQL | SPARQL Protocol and RDF Query Language — the standard query language for RDF databases (triple stores). | SELECT ?s ?p ?o WHERE { ?s ?p ?o } to query a graph. |
TSV | Tab-Separated Values — plain text tabular format using tabs as delimiters. | users.tsv exports with tab‑delimited fields. |
Legacy | ||
FOAF | Friend of a Friend — one of the earliest and most famous Semantic Web ontologies, used to describe people and their relationships. | Define a person's profile using foaf:Person , foaf:name , foaf:knows . |
JSONP | JSON with Padding — legacy technique to circumvent same‑origin policy by wrapping JSON in a callback for script tags. | callback({ ... }) responses consumed via <script> ; replaced by CORS. |
MARC | Machine-Readable Cataloging — a standard for the representation and communication of bibliographic and related information in machine-readable form. | Library automation systems use MARC records to manage catalogs. |
RSS | Really Simple Syndication — XML-based web feed format for publishing updates. | Blog feed at /feed.xml ; subscribe in a feed reader. |
Data Formats (Compression & Archival)
Acronym | Meaning | Example |
---|---|---|
7z | 7‑Zip archive format — open archive container supporting solid compression, advanced filters, and high ratios via LZMA/LZMA2 and others. | Create/extract with 7z a archive.7z files/ and 7z x ; widely used for high‑ratio packaging. |
BZIP2 | Burrows–Wheeler block-sorting compressor — high compression ratio with moderate CPU cost; slower than gzip, faster than xz in many cases. | Compress archives/logs: bzip2 file , tar -cjf archive.tar.bz2 dir/ ; .bz2 packages. |
DEFLATE | Lossless compression format combining LZ77 sliding‑window dictionary with Huffman coding; ubiquitous in ZIP, gzip, and PNG. | Compress HTTP responses (Content‑Encoding: gzip/deflate ), ZIP entries, and PNG image data. |
GZIP | GNU Zip — widely used lossless compression format using DEFLATE (LZ77+Huffman); good balance of speed and ratio. | Compress streams/files: gzip file , tar -czf archive.tar.gz dir/ ; HTTP Content-Encoding: gzip . |
JAR | Java ARchive — ZIP‑based archive format for packaging Java classes/resources and metadata (META-INF/MANIFEST.MF ); supports signing and class‑path entries. | Build/run .jar apps (jar cfm app.jar MANIFEST.MF -C out/ . ); libraries on the classpath; fat/uber JARs bundle deps. |
LZ4 | Extremely fast lossless compression algorithm optimized for speed with modest compression ratios. | Compress logs/IPC payloads with LZ4 for low latency; .lz4 frames. |
LZ77 | Lempel–Ziv 1977 — dictionary-based lossless compression using a sliding window and back‑references (length, distance) to past data. | Foundation for DEFLATE (gzip/ZIP) and many formats; emits literals and copy tokens. |
LZMA | Lempel–Ziv–Markov chain Algorithm — high‑ratio lossless compression with larger memory use and slower speeds than DEFLATE; foundation for 7z and XZ (LZMA2). | Create 7z archives with LZMA/LZMA2; xz uses LZMA2 for .xz /.tar.xz . |
RAR | Roshal Archive — proprietary archive format supporting solid compression, recovery records, and strong encryption; widely used but not fully open. | Create/extract with WinRAR/rar /unrar ; .rar multi‑part volumes; consider 7z/zip for openness. |
RLE | Run-Length Encoding — simple lossless compression that replaces runs of repeated symbols with a count and value. | Bitmap/scanline compression (e.g., BMP RLE, fax/CCITT variants); good for large uniform areas. |
TAR | Tape ARchive — stream/archive format that bundles multiple files/directories with metadata into a single sequential archive; often compressed (e.g., .tar.gz/.tgz). | Create/extract backups: tar -czf backup.tgz dir/ ; used for packaging and distribution. |
XZ | XZ Utils format — high‑ratio lossless compression using LZMA2 with solid archives and strong compression at the cost of CPU/time. | Compress release artifacts/logs: tar -cJf , xz -T0 file ; .tar.xz packages in Linux distros. |
ZIP | ZIP archive format — ubiquitous container supporting per‑file compression (typically DEFLATE), random access, and metadata; widely supported on all platforms. | .zip files; zip /unzip ; JAR/APK/Office Open XML use ZIP containers. |
ZSTD | Zstandard — modern fast lossless compression algorithm offering high ratios with very high decompression speed; supports dictionaries. | Compress artifacts/logs with zstd; .zst files; use dictionaries for small data. |
Legacy | ||
LZW | Lempel–Ziv–Welch — dictionary-based lossless compression algorithm historically used in GIF and some TIFF variants; now patent-free. | Classic GIF image compression; replace with PNG for lossless images. |
Data Processing
Acronym | Meaning | Example |
---|---|---|
ACID | Atomicity, Consistency, Isolation, Durability — transaction guarantees. | Bank transfer completes fully or not at all. |
ADO.NET | ActiveX Data Objects .NET — the modern data access framework for the .NET platform, succeeding classic ADO. | SqlConnection and DataSet for database operations in C#/VB.NET. |
BASE | Basically Available, Soft state, Eventual consistency — distributed tradeoff. | Eventual consistency across regions. |
BI | Business Intelligence — processes/tools to analyze business data for insights and decision‑making. | Dashboards and reports in Looker/Power BI over a warehouse. |
BLOB | Binary Large Object — large binary field in a DB. | Store images/files as BLOBs or in object storage. |
CAP | Consistency, Availability, Partition tolerance — favor two under partition. | AP systems may return stale data during splits. |
CBO | Cost-Based Optimizer — query planner that chooses execution plans by estimating cost using statistics. | Analyze stats; planner picks index scan vs full scan. |
CDC | Change Data Capture — stream DB changes. | Debezium publishes events to Kafka. |
CRDT | Conflict-free Replicated Data Type — data structures that merge deterministically without coordination for eventual consistency. | LWW-Element-Set, G-Counter; collaborative docs with Automerge/Yjs. |
CTE | Common Table Expression — named temporary result set referenced within a statement. | WITH recent AS (SELECT ...) SELECT * FROM recent WHERE ... . |
DB | Database — organized data managed by a DBMS. | Postgres/MySQL database with tables, indexes, and transactions. |
DB2 | DB2 — IBM's family of relational database management systems (RDBMS) running on platforms from Linux/Unix/Windows to mainframes (z/OS). | Enterprise data warehousing and OLTP on DB2 for z/OS or LUW. |
DBMS | Database Management System — software that manages databases, provides storage, query, and transaction processing. | PostgreSQL, MySQL, SQLite, Oracle, SQL Server. |
DDL | Data Definition Language — SQL for defining/modifying schema objects. | CREATE TABLE , ALTER TABLE , CREATE INDEX . |
DLQ | Dead Letter Queue — holding queue/topic for messages/events that could not be processed or delivered after retries, isolating poison messages for inspection and remediation. | SQS redrive policy sends failed messages to a DLQ; Kafka error/"-dlq" topic. |
DML | Data Manipulation Language — SQL for querying and changing data. | SELECT , INSERT , UPDATE , DELETE . |
DW | Data Warehouse — centralized, integrated repository optimized for analytics. | Snowflake/BigQuery/Redshift with star/snowflake schemas. |
EF | Entity Framework — Microsoft's object-relational mapping (ORM) framework for .NET. | Map database tables to C# objects with EF Core; use LINQ to query data. |
ELT | Extract, Load, Transform — load raw data then transform in the warehouse. | Modern ELT with dbt/BigQuery. |
ERD | Entity Relationship Diagram — visual schema modeling notation that captures entities, their attributes, and relationships/cardinalities before implementing a database. | Sketch an ERD in crow's-foot notation to model Customer –Order –OrderLine relationships prior to creating tables. |
ETL | Extract, Transform, Load — data integration pipeline. | Batch load to data warehouse. |
FK | Foreign Key — constraint that enforces referential integrity by requiring values to exist in a referenced table. | orders.user_id references users.id ; ON DELETE CASCADE. |
GIS | Geographic Information System — system for capturing, storing, analyzing, and managing spatial or geographic data. | Analyze spatial data with ArcGIS or QGIS; build location-aware apps. |
HLL | HyperLogLog — probabilistic algorithm for cardinality (distinct count) estimation that uses fixed, small memory with tunable relative error via stochastic averaging of leading-zero counts. | Approximate unique users/events with ~1–2% error using kilobytes of memory; streaming distinct counts in analytics pipelines. |
LSMT | Log-Structured Merge-Tree — write-optimized indexing/storage structure that buffers writes in memory and flushes them as sorted runs (SSTables) to disk, with background compaction/merging; lowers random writes at the cost of read/space amplification. | Used by LevelDB/RocksDB; LSM-based stores like Cassandra and HBase. |
MQ | Message Queue — durable, asynchronous messaging channel that buffers messages between producers and consumers to decouple services and smooth load. | RabbitMQ/SQS enqueue events; workers consume from the queue to process jobs off the critical path. |
MVCC | Multi-Version Concurrency Control — concurrency control that lets readers and writers proceed by keeping multiple row versions and using snapshot visibility rules. | PostgreSQL snapshot reads; VACUUM removes obsolete versions. |
NoSQL | Non-relational DBs: documents, key-values, graphs, wide columns. | MongoDB, Redis, Cassandra. |
OLAP | Online Analytical Processing — read-heavy analytics. | BI cubes, columnar stores. |
OLTP | Online Transaction Processing — write-heavy transactions. | Order processing systems. |
PK | Primary Key — unique, non-null identifier for a table row. | users(id UUID PRIMARY KEY) ; composite keys across columns. |
RDBMS | Relational Database Management System — DBMS based on the relational model using tables, rows, and SQL with constraints and ACID transactions. | PostgreSQL, MySQL, SQL Server, Oracle; normalized schemas and joins. |
RDD | Resilient Distributed Dataset — fault-tolerant distributed collection in Apache Spark enabling parallel transformations across partitions with lineage-based recovery. | Spark job transforms an RDD with rdd.map() /filter() and caches it via persist() for reuse. |
SQL | Structured Query Language — query/manage relational DBs. | SELECT * FROM users . |
WAL | Write-Ahead Logging — durability mechanism that writes log records before data pages. | PostgreSQL WAL for crash recovery and replication. |
Legacy | ||
ADO | ActiveX Data Objects — a legacy Microsoft data access framework for connecting to databases from languages like classic VB and ASP. | ADODB.Connection and Recordset objects for database queries. |
CICS | Customer Information Control System — IBM mainframe transaction processing monitor that provides high-volume, secure, and reliable online transaction processing. | Legacy banking and airline systems running CICS transactions. |
CODASYL | Conference/Committee on Data Systems Languages — consortium behind COBOL and the DBTG network database model that specified schemas, subschemas, and navigation APIs for early DBMS. | CODASYL DBTG specs defined the network data model adopted by IDS, IDMS, and other mainframe DBMSs. |
DAO | Data Access Objects — a legacy Microsoft data access API primarily used for accessing Jet (Microsoft Access) databases. | Predecessor to ADO; used heavily in classic VB applications. |
IDMS | Integrated Database Management System — commercial network database derived from IDS, providing CODASYL DBTG-compliant data/navigation on IBM mainframes. | CA-IDMS on IBM z/OS runs core enterprise apps using CODASYL sets and schemas. |
IDS | Integrated Data Store — Charles Bachman’s pioneering network database management system for GE mainframes, influencing CODASYL DBTG standards and later products like IDMS. | Run IDS/II on GE 600/635 systems to model hierarchical/network data; precursor to commercial IDMS releases. |
IMS | Information Management System — IBM's combined hierarchical database and transaction manager for mainframes, a precursor to relational databases. | High-performance transaction processing on z/OS; IMS DB/DC. |
OLE DB | Object Linking and Embedding, Database — a low-level Microsoft API for accessing a wide variety of data sources. | The underlying interface for ADO; connect to SQL Server via the OLE DB provider. |
RDO | Remote Data Objects — a legacy Microsoft data access API for remote relational databases, superseded by ADO. | Early client-server applications in Visual Basic connecting to SQL Server. |
VSAM | Virtual Storage Access Method — the primary data storage method on IBM z/OS for structured data. | Key-sequenced datasets (KSDS) used by CICS and batch applications. |
Artificial Intelligence
Acronym | Meaning | Example |
---|---|---|
AI | Artificial Intelligence — techniques that enable machines to perform tasks associated with human intelligence (learning, perception, reasoning). | Use ML/DL models to power AI features like recommendations. |
ANN | Artificial Neural Network — computational model inspired by biological neurons, used for function approximation and pattern recognition. | MLPs for tabular data; feedforward nets for classification. |
CNN | Convolutional Neural Network — neural network architecture specialized for grid‑like data using convolutional filters. | Image classification/segmentation models. |
CoT | Chain-of-Thought — prompting technique to elicit step-by-step reasoning. | "Let's think step by step" to improve math/logic. |
GPT | Generative Pre-trained Transformer — transformer-based LLM architecture pre-trained on large text corpora and fine-tuned for tasks. | GPT-4 class models for chat, code, and reasoning. |
LLM | Large Language Model — NLP model for generation/reasoning. | GPT/Llama used via APIs or locally. |
MCP | Model Context Protocol — open protocol to expose tools/data to LLM clients via standardized servers. | Run an MCP server to provide DB/filesystem tools to an LLM client. |
MoE | Mixture of Experts — sparse expert routing to scale parameters with near-constant compute. | Router selects top‑k experts per token (Switch-Transformer). |
NER | Named Entity Recognition — extract and label entities in text. | Tag PERSON/ORG/LOC from documents. |
NLP | Natural Language Processing — techniques for understanding and generating human language. | Text classification, NER, summarization, translation. |
OCR | Optical Character Recognition — convert images/scans of text into machine‑encoded text using computer vision and sequence models. | Tesseract or deep‑learning OCR to extract text from documents/receipts. |
RAG | Retrieval-Augmented Generation — ground model outputs by retrieving external knowledge at query time. | Retrieve top‑k docs from a vector store and include them in the prompt. |
RL | Reinforcement Learning — learning by interaction with an environment via rewards. | Q‑learning, policy gradients; RLHF for model alignment. |
RLHF | Reinforcement Learning from Human Feedback — align models using human preference signals via a learned reward model. | Collect preference pairs, train a reward model, then fine‑tune with PPO. |
RNN | Recurrent Neural Network — sequence model with recurrent connections. | LSTM/GRU for language modeling and time series. |
SFT | Supervised Fine-Tuning — fine‑tune a pretrained model on labeled input–output pairs to specialize behavior. | Fine‑tune a base LLM on instruction datasets before RLHF. |
TTS | Text-to-Speech — synthesize speech audio from text. | Generate spoken responses from a chatbot. |
VLM | Vision-Language Model — jointly processes images and text. | CLIP, BLIP, LLaVA for captioning and VQA. |
Reliability & Operations
Acronym | Meaning | Example |
---|---|---|
DR | Disaster Recovery — restore service after catastrophic failure. | DR runbooks; backup restore drills. |
HA | High Availability — design to minimize downtime. | Multi-zone deployment with failover. |
MTTR | Mean Time To Repair/Recover — restore time after failure. | Track MTTR per incident. |
RCA | Root Cause Analysis — identify underlying cause. | Postmortem documents. |
RPO | Recovery Point Objective — max acceptable data loss. | 5-minute RPO via frequent backups. |
RTO | Recovery Time Objective — target restore time. | 30-minute RTO for tier-1 services. |
SLA | Service Level Agreement — contractual target. | 99.9% monthly uptime. |
SLI | Service Level Indicator — measured metric. | Request success rate, p95 latency. |
SLO | Service Level Objective — internal target. | 99.95% quarterly availability. |
SPOF | Single Point Of Failure — outage if it fails. | Single DB primary without replica. |
SRE | Site Reliability Engineering — SWE meets ops. | Error budgets, toil reduction. |
Performance & Metrics
Acronym | Meaning | Example |
---|---|---|
Apdex | Application Performance Index — satisfaction score based on latency thresholds. | Apdex ≥ 0.9 target. |
APM | Application Performance Monitoring — traces/metrics/errors for apps. | Distributed tracing spans across services. |
CLS | Cumulative Layout Shift — visual stability (Web Vitals). | CLS < 0.1. |
FLOPS | Floating-Point Operations Per Second — measure of compute performance for CPUs/GPUs/accelerators. | GPU rated at 30 TFLOPS; benchmark sustained vs peak GFLOPS. |
FPS | Frames Per Second — render/update frequency for graphics/video; higher is smoother within latency/refresh constraints. | Games target 60+ FPS; VR aims for 90–120 FPS. |
INP | Interaction to Next Paint — user input responsiveness (Web Vitals). | INP < 200 ms. |
IOPS | Input/Output Operations Per Second — storage throughput measurement. | NVMe SSD sustaining 500k+ random read IOPS. |
IPC | Instructions Per Clock/Cycle — measure of a CPU's architectural efficiency, independent of clock speed. | A CPU with higher IPC can be faster than one with a higher clock rate. |
LCP | Largest Contentful Paint — main content render time (Web Vitals). | LCP < 2.5 s. |
LoC | Lines of Code — simple size metric counting source lines; can indicate scope but is a poor proxy for complexity or value. | Compare module sizes; avoid using LoC alone for productivity. |
MIPS | Million Instructions Per Second — rough measure of integer instruction throughput; varies widely by ISA and instruction complexity. | Historical CPU comparisons; not comparable across architectures/workloads. |
P50/P95/P99 | Latency percentiles — response time distribution. | P95 latency under 250 ms. |
RPS/QPS | Requests/Queries Per Second — service throughput. | API serves 2k RPS at peak. |
RUM | Real User Monitoring — measurements from real users. | In-browser beacons for Web Vitals. |
TPS | Transactions Per Second — business-level throughput. | Payments at 150 TPS during sale. |
TTFB | Time To First Byte — time to first response byte. | Aim for TTFB < 200 ms. |
TTI | Time To Interactive — page becomes reliably usable. | TTI ~ 3.0 s. |
Networking & Protocols
Acronym | Meaning | Example |
---|---|---|
AMQP | Advanced Message Queuing Protocol — open standard for asynchronous messaging between applications, enabling reliable, interoperable, and feature-rich communication. | RabbitMQ/ActiveMQ brokers implementing AMQP 0-9-1 or 1.0 for queuing and routing. |
ARP | Address Resolution Protocol — map IP addresses to MAC addresses on a LAN. | ARP cache; gratuitous ARP. |
AS | Autonomous System — a collection of IP networks under a single administrative control, identified by an ASN and used in BGP routing. | An ISP, a university, or a large tech company's network. |
ASN | Autonomous System Number — a globally unique identifier for a network, used in BGP routing. | ISP route announcements include their ASN; AS15169 is Google's ASN. |
BGP | Border Gateway Protocol — inter-domain routing protocol of the internet. | ISP peering and route advertisements. |
BIND | Berkeley Internet Name Domain — a widely used, open-source DNS server. | Configure zones in named.conf ; query a BIND server with dig . |
BPF | Berkeley Packet Filter — kernel-level virtual machine for packet filtering/observability (eBPF on modern kernels). | Capture packets with tcpdump; eBPF programs for tracing. |
CIDR | Classless Inter-Domain Routing — notation for IP prefixes and aggregation. | 10.0.0.0/16 VPC; subnetting /24 ; route summarization. |
CNAME | Canonical Name — DNS record that aliases one hostname to another. | www CNAME to example.com ; avoid at zone apex without ALIAS/ANAME. |
CRC | Cyclic Redundancy Check — an error-detecting code used to detect accidental changes to digital data. | Ethernet frame check sequence (FCS); CRC-32 in ZIP/PNG files. |
DHCP | Dynamic Host Configuration Protocol — automatic IP configuration. | DHCP assigns IP/gateway/DNS. |
DHT | Distributed Hash Table — decentralized key-value store that partitions data across a peer-to-peer network, enabling scalable lookups without a central server. | BitTorrent Mainline DHT for peer discovery; IPFS for content addressing. |
DoH | DNS over HTTPS — perform DNS resolution over HTTPS for privacy/integrity. | https://dns.google/dns-query DoH endpoint. |
FC | Fibre Channel — high‑speed serial transport for storage networking (SANs) with switched fabrics, typically 8/16/32 Gbit/s, carrying SCSI/FCP. | Connect hosts to SAN arrays over FC via HBAs and switches; zoning and LUN masking. |
HTTP | Hypertext Transfer Protocol — web application protocol. | GET /index.html over TCP. |
HTTPS | HTTP over TLS — encrypted HTTP. | Padlock in browsers. |
ICMP | Internet Control Message Protocol — diagnostics/control. | ping uses Echo Request/Reply. |
IMAP | Internet Message Access Protocol — email retrieval/sync. | Mail clients syncing mailboxes. |
IP | Internet Protocol — addressing/routing (IPv4/IPv6). | Packet delivery across networks. |
IPsec | Internet Protocol Security — suite of protocols for authenticating and encrypting IP packets at the network layer (AH/ESP) with key exchange via IKE. | Site-to-site or remote-access VPNs using IKEv2 with ESP in tunnel mode; transport mode for host-to-host. |
iSCSI | Internet Small Computer Systems Interface — block storage protocol that encapsulates SCSI commands over TCP/IP. | Connect initiators to targets on port 3260; boot from SAN; map LUNs over the network. |
ISP | Internet Service Provider — company that provides internet connectivity and related services. | Residential broadband, business fiber links, and transit. |
L2TP | Layer 2 Tunneling Protocol — encapsulates PPP frames to create tunnels across IP networks, typically paired with IPsec for encryption/authentication. | Remote-access VPN uses L2TP over IPsec (UDP 1701/500/4500) to tunnel client traffic through a secure gateway. |
LAN | Local Area Network — network covering a limited geographic area such as a home, office, or campus. | Ethernet/Wi‑Fi LAN with switches and access points. |
LDAP | Lightweight Directory Access Protocol — protocol for accessing and managing directory services. | Authenticate/lookup users and groups in an LDAP directory. |
MAC | Media Access Control — data-link sublayer that governs medium access, framing, and addressing on LANs. | Ethernet MAC handles frame delimiting, MAC addressing, and channel access. |
MPLS | Multiprotocol Label Switching — high-performance packet forwarding that uses short labels to make traffic-engineered L2.5 paths across provider cores. | ISP backbone uses MPLS L3VPNs/TE to steer customer traffic and provide QoS across the WAN. |
MQTT | Message Queuing Telemetry Transport — lightweight publish-subscribe protocol for constrained devices and low-bandwidth, high-latency networks; widely used in IoT. | IoT sensors publishing telemetry to an MQTT broker; mobile push notifications. |
MTU | Maximum Transmission Unit — largest payload size (in bytes) that can be sent in a single layer‑2 frame without fragmentation. | Ethernet MTU 1500; jumbo frames MTU 9000; Path MTU Discovery avoids fragmentation. |
MX | Mail Exchanger — DNS record that specifies the mail servers responsible for accepting email for a domain, with preferences for priority/failover. | example.com. MX 10 mail1.example.com. and MX 20 mail2.example.com. as backup. |
NAT | Network Address Translation — remap private to public addresses. | Home routers performing PAT. |
NFS | Network File System — distributed file system protocol for sharing files over a network. | Mount remote directories via NFSv3/NFSv4. |
NS | Name Server — DNS server authoritative for a zone; also the DNS record type that delegates to authoritative servers. | NS records pointing to ns1.example.com for a domain. |
NTP | Network Time Protocol — synchronize clocks over networks using a hierarchy of time sources. | chrony /ntpd syncing to NTP servers (stratum levels). |
OSI | Open Systems Interconnection — conceptual seven‑layer networking reference model for describing protocols and interoperability (Layers 1–7: Physical→Application). | Map protocols to layers (e.g., Ethernet=L2, IP=L3, TCP=L4, HTTP=L7); teaching/troubleshooting taxonomy. |
OSPF | Open Shortest Path First — interior gateway routing protocol. | Multi-area OSPF in enterprises. |
P2P | Peer-to-Peer — decentralized communication model where nodes act as both clients and servers without a central coordinator. | BitTorrent swarms; WebRTC data channels; DHT-based peer discovery. |
PoE | Power over Ethernet — standard for providing electrical power through Ethernet cables to devices like IP cameras, VoIP phones, and wireless access points. | 802.3af/at/bt standards for PoE/PoE+/PoE++. |
QoS | Quality of Service — mechanisms that classify and prioritize traffic to meet latency, jitter, and loss requirements. | Configure DiffServ/DSCP queues on routers to give voice and video higher priority than bulk data. |
QUIC | Quick UDP Internet Connections — encrypted, multiplexed transport over UDP. | HTTP/3 runs over QUIC. |
RDP | Remote Desktop Protocol — a proprietary protocol from Microsoft for remote access to a graphical user interface on a Windows machine. | Connect to a Windows server with an RDP client; mstsc.exe . |
SFTP | SSH File Transfer Protocol — file transfer over SSH. | sftp user@host uploads/downloads. |
SMB | Server Message Block — network file/printer sharing protocol used mainly by Windows; modern versions (SMBv2/v3) support signing/encryption. | Mount \\server\share ; Samba on Unix; avoid SMBv1 due to security issues. |
SMTP | Simple Mail Transfer Protocol — send email. | MTA relaying messages. |
SNMP | Simple Network Management Protocol — protocol for monitoring and managing networked devices via a hierarchical MIB of OIDs, supporting polling and asynchronous traps/informs. | Poll interfaces/CPU via GET/GETNEXT/GETBULK; receive traps; v1/v2c (community) and v3 (auth/privacy). |
SSE | Server-Sent Events — HTTP-based server→client stream. | EventSource('/events') . |
STP | Spanning Tree Protocol — network protocol that ensures a loop-free topology for bridged Ethernet networks. | Switches running STP/RSTP to prevent broadcast storms. |
TCP | Transmission Control Protocol — reliable byte stream. | HTTP, TLS use TCP. |
TCP/IP | Transmission Control Protocol / Internet Protocol — foundational internet protocol suite encompassing transport, network, and related layers. | Classic network stack model; "TCP/IP networking" on UNIX systems. |
TLD | Top-Level Domain — the highest level in the DNS hierarchy, forming the rightmost label of a domain name. | .com , .org , country-code TLDs like .uk ; ICANN-managed root zone. |
TTL | Time To Live — lifetime for packets/cached records. | DNS TTL controls cache duration. |
UDP | User Datagram Protocol — connectionless, low-latency. | DNS, streaming. |
UNC | Universal Naming Convention — Windows network path notation for accessing resources by server/share. | \\\\server\\share\\folder\\file.txt ; used with SMB. |
VLAN | Virtual Local Area Network — Layer 2 network segmentation on a switch, isolating broadcast domains; tagging via IEEE 802.1Q. | VLAN 10/20 on access/trunk ports; tagged vs untagged frames. |
WAN | Wide Area Network — network spanning large geographic areas interconnecting LANs over provider links or the public internet. | MPLS links, SD‑WAN, site‑to‑site VPN between offices. |
WebRTC | Web Real-Time Communication — a framework providing browsers and mobile applications with real-time communication (RTC) capabilities via simple APIs. | Peer-to-peer video conferencing, screen sharing, and data channels in the browser. |
WHOIS | WHOIS protocol — query/response protocol for retrieving registration information about internet resources such as domain names and IP address allocations. | whois example.com to get registrar/registrant data; RDAP is the modern HTTP-based successor. |
WS | WebSocket — full-duplex over single TCP connection. | ws://example.com/socket . |
WSS | WebSocket Secure — WebSocket over TLS. | wss://example.com/socket . |
Legacy | ||
ADSL | Asymmetric Digital Subscriber Line — a common type of DSL where download speeds are faster than upload speeds. | Consumer broadband over telephone lines. |
CSU | Channel Service Unit — legacy telco/customer-premises device that terminates a digital leased circuit, provides line conditioning/loopback diagnostics, and hands off a clean interface to a paired DSU or router. | Standalone CSU on a T1 line or integrated CSU/DSU modules in enterprise routers delivering telco-managed point-to-point links. |
DCE | Data Circuit-terminating Equipment — provides clocking, signal conversion, and circuit termination for serial/WAN links so attached DTEs can communicate. | CSU/DSU, cable/DSL modems, and telco demarc gear act as the DCE in leased-line setups. |
DSL | Digital Subscriber Line — a family of technologies for transmitting digital data over telephone lines. | ADSL, SDSL, VDSL are all types of DSL. |
DSU | Data Service Unit — legacy digital modem that converts the CSU-provided line signal into synchronous serial presented to DTE gear, completing the CSU/DSU pair on leased circuits. | External DSUs or router interface cards carrying T1/E1 circuits expose V.35/RS-449 ports for routers/terminals. |
DTE | Data Terminal Equipment — end device that connects to a DCE to originate or receive data on a serial/WAN circuit, typically providing clocking recovery from the DCE. | Routers, terminals, or customer-edge gear plugging into a CSU/DSU; use show controllers serial to verify DTE/DCE role via cable pinout. |
FTP | File Transfer Protocol — legacy, unencrypted by default. | ftp client for file transfers. |
FTPS | FTP over TLS — encrypted FTP. | Implicit/explicit FTPS modes. |
iPXE | Open-source network boot firmware/bootloader extending PXE with HTTP(S), iSCSI, FCoE, AoE, scripts, and TLS. | Chainload iPXE via PXE; fetch an HTTPS boot script to load kernel/initrd. |
IRC | Internet Relay Chat — real-time text messaging protocol and networks for group channels and direct messages. | Join #project on Libera Chat using irssi or WeeChat. |
NBT | NetBIOS over TCP/IP — transport that carries NetBIOS name, datagram, and session traffic over TCP/UDP (ports 137–139) so legacy NetBIOS applications work on IP networks. | Keep NBT only for backward compatibility with old Windows clients/printers; disable when moving fully to DNS/SMB over TCP 445. |
NetBEUI | NetBIOS Extended User Interface — non-routable, broadcast-heavy transport protocol for NetBIOS communications on small LANs; superseded by NBT/TCP/IP. | Early Windows peer-to-peer networking used NetBEUI; administrators removed it when migrating to TCP/IP-based SMB. |
NetBIOS | Network Basic Input/Output System — legacy API and naming services that provided session/datagram communication atop early LAN transports (NetBEUI, IPX/SPX, later NBT). | DOS/Windows for Workgroups apps used NetBIOS names for SMB file/print sharing; modern AD domains phase out NetBIOS names in favor of DNS. |
NIS | Network Information Service — a legacy Unix directory service for distributing system configuration data like user and host names between computers on a network. | Originally known as Yellow Pages (YP); superseded by LDAP. |
NNTP | Network News Transfer Protocol — application protocol for distributing, querying, and posting Usenet articles over TCP. | Connect to Usenet servers on 119 (or 563 for NNTPS) to read/post news. |
POP3 | Post Office Protocol v3 — simple email retrieval. | Fetch-and-delete mailbox flow. |
PPP | Point-to-Point Protocol — data link layer protocol for encapsulating network traffic over serial links; supports authentication, compression, and multilink. | Dial-up links; PPPoE for broadband; CHAP/PAP authentication. |
PPTP | Point-to-Point Tunneling Protocol — legacy VPN tunneling protocol that encapsulates PPP over GRE with MPPE encryption; considered insecure and deprecated. | Historical Windows VPNs using PPTP; replace with IPsec/OpenVPN/WireGuard/L2TP over IPsec. |
PXE | Preboot Execution Environment — standard for network booting clients using DHCP/BOOTP to obtain boot info and TFTP/HTTP to fetch boot loaders/images. | PXE boot a workstation from a provisioning server into an installer. |
RIP | Routing Information Protocol — distance-vector interior gateway protocol using hop count as its metric with periodic full-table updates. | RIP v2 on small LANs; max 15 hops; split horizon/poison reverse to mitigate loops. |
RLOGIN | Remote Login — BSD plaintext remote login protocol; superseded by SSH. | rlogin host for interactive sessions on legacy UNIX systems. |
RSH | Remote Shell — BSD plaintext remote command execution; superseded by SSH. | rsh host command on legacy UNIX; avoid due to lack of security. |
TFTP | Trivial File Transfer Protocol — simple UDP-based file transfer protocol commonly used for network boot and configuration. | PXE firmware downloads boot images via TFTP; no auth/encryption. |
UPnP | Universal Plug and Play — discovery and control protocols for devices/services on a local network; includes IGD for NAT port mappings. | Home routers auto‑open ports via UPnP IGD; device discovery/control on LANs. |
VDSL | Very-high-bit-rate Digital Subscriber Line — a faster version of DSL, often used for fiber-to-the-curb deployments. | Higher speeds over shorter distances than ADSL. |
WINS | Windows Internet Name Service — Microsoft's legacy database-backed NetBIOS name resolution service that replicates between servers and integrates with DHCP for old Windows clients. | Maintain WINS servers in mixed Active Directory environments; DHCP option 44/46 hands out WINS server IPs to legacy nodes. |
XMPP | Extensible Messaging and Presence Protocol — open, federated XML-based protocol for instant messaging and presence. | Jabber, Google Talk (legacy); used in federated chat and IoT. |
Historical | ||
AIM | AOL Instant Messenger — a pioneering instant messaging service from AOL, popular in the late 1990s and 2000s. | Buddy Lists, away messages, and chat sounds. |
ARPANET | Advanced Research Projects Agency Network — pioneering packet‑switched network and direct precursor to the modern Internet. | 1969 UCLA–SRI link; IMPs; 1983 cutover from NCP to TCP/IP. |
ATM | Asynchronous Transfer Mode — a telecommunications standard for cell-based switching, designed for high-speed voice, video, and data. | Used in telco backbones and for DSL; superseded by IP-based networks. |
BBS | Bulletin Board System — pre‑web dial‑up systems. | Modem dial‑ins for forums/files before the web. |
BITNET | Because It’s Time Network — early academic store-and-forward network linking universities via leased lines using IBM’s RSCS protocol; provided email, file transfer, and LISTSERV mailing lists. | Colleges connected mainframes to BITNET in the 1980s; LISTSERV communities flourished before widespread internet access. |
BOOTP | Bootstrap Protocol — assigns IP configuration to diskless clients at boot, predecessor to DHCP. | Network boot ROM requests IP/gateway/TFTP server; largely replaced by DHCP. |
CSMA/CD | Carrier-Sense Multiple Access with Collision Detection — media access control method used by early Ethernet on a shared bus. | Half-duplex hubs; nodes listen before transmitting and detect collisions. |
CSNET | Computer Science Network — an early computer network that provided services to university computer science departments, funded by the NSF. | A key stepping stone between ARPANET and the modern internet. |
DECnet | Digital Equipment Corporation's proprietary network protocol suite for DEC systems; largely superseded by TCP/IP. | VAX/VMS clusters and DEC systems communicating over DECnet Phase IV/V. |
ICQ | "I Seek You" — one of the first internet-wide instant messaging services. | User identification numbers (UINs) and the "uh-oh!" sound. |
IPX | Internetwork Packet Exchange — Novell's network-layer protocol used with SPX and NetWare; replaced by IP in modern networks. | Legacy NetWare LANs using IPX addressing and routing. |
ISDN | Integrated Services Digital Network — circuit‑switched digital telephony offering voice and data over PSTN with separate bearer/signaling channels. | BRI (2B+D) for small sites; PRI (23B+D NA / 30B+D EU) for trunks. |
MSN | The Microsoft Network — an early online service and ISP from Microsoft, later known for its web portal and instant messenger. | MSN Messenger was a major competitor to AIM and ICQ. |
NCP | NetWare Core Protocol — Novell NetWare file/print service protocol suite running over IPX/SPX (later IP). | Legacy NetWare clients mapping drives/printers via NCP. |
NCP | Network Control Program — early ARPANET host protocol providing a transport layer and flow control prior to the adoption of TCP/IP. | Used until the 1983 flag day cutover to TCP/IP; sockets over NCP. |
NDS | Novell Directory Services — directory service for managing identities, resources, and access in Novell NetWare environments (later evolved into eDirectory). | Centralized users/groups/policies across NetWare; replaced/renamed as eDirectory. |
NSFNET | National Science Foundation Network — U.S. government-funded backbone that expanded academic access to the ARPANET successor, catalyzing the transition to today’s commercial internet before its 1995 decommissioning. | Regional networks connected to NSFNET T1/T3 backbones; commercial ISPs emerged as NSFNET traffic opened to broader use. |
PAD | Packet Assembler/Disassembler — X.25-era device that buffered character-stream or async terminal traffic and converted it to packets for a public data network (and vice versa). | Retail POS terminals or green-screen async devices connected through a PAD to reach hosts over public X.25 services. |
PUP | PARC Universal Packet — early internetworking protocol suite developed at Xerox PARC that influenced XNS and later networking concepts. | Historical LAN internetworking; precursor to concepts adopted in later stacks. |
RARP | Reverse Address Resolution Protocol — legacy protocol for discovering an IP address given a MAC address. | Early diskless boot; superseded by BOOTP/DHCP. |
SLIP | Serial Line Internet Protocol — simple encapsulation of IP over serial links; lacks features like authentication, negotiation, and error detection. | Early dial-up IP connectivity; superseded by PPP. |
SNA | Systems Network Architecture — IBM's proprietary networking architecture for mainframes and enterprise networks; largely superseded by TCP/IP. | IBM 3270/5250 terminals and LU types; later SNA over IP via Enterprise Extender. |
SPX | Sequenced Packet Exchange — Novell's transport-layer protocol running over IPX, analogous to TCP; superseded by TCP/IP. | NetWare clients/servers using IPX/SPX for file/print services. |
UUCP | Unix-to-Unix Copy Protocol — store-and-forward system for transferring files, email, and netnews over dial-up/serial links; pre-internet era networking. | Early email/news via bang paths (uucp!host!user); largely replaced by SMTP/NNTP over IP. |
UUNET | Unix-to-Unix Network — one of the first commercial internet service providers, evolving from a Usenet feed service into a major backbone operator that helped commercialize internet access. | Provided UUCP/Usenet feeds, then IP transit and dial-up services before mergers into MCI/WorldCom. |
WAIS | Wide Area Information Servers — early distributed document indexing/search and retrieval system predating modern web search; used client/server over Z39.50. | 1990s internet search across WAIS servers before mainstream web engines. |
X.25 | ITU-T legacy packet-switched WAN protocol using virtual circuits over carrier networks; superseded by Frame Relay/ATM/IP. | Early bank/pos/leased-line links using X.25 PADs and PVC/SVC connections. |
XNS | Xerox Network Systems — Xerox's network protocol suite from PARC that influenced later protocols (e.g., IPX/SPX, AppleTalk). | Historical LAN stack alongside SNA/DECnet; precursor ideas to modern networking. |
Security
Acronym | Meaning | Example |
---|---|---|
2FA | Two-Factor Authentication — two independent proofs of identity. | Password + TOTP device. |
ABAC | Attribute-Based Access Control — attribute-driven permissions. | Policies on user/resource attributes. |
ACL | Access Control List — list of permissions attached to an object specifying which principals are allowed which operations. | Filesystem/network ACLs granting read/write/execute or allow/deny rules. |
AES | Advanced Encryption Standard — widely used symmetric block cipher (Rijndael) with 128‑bit blocks and 128/192/256‑bit keys. | AES‑GCM for TLS and at‑rest encryption. |
BYOD | Bring Your Own Device — policy allowing use of personal devices for work, requiring security controls and management. | Enforce MDM, device compliance, and conditional access for email/apps. |
BYOK | Bring Your Own Key — customer-managed encryption keys used with a cloud provider’s services instead of provider‑managed keys. | Store CMKs in KMS/HSM; configure services to use them; rotate regularly. |
CA | Certificate Authority — issues digital certificates (X.509). | Let's Encrypt TLS certs. |
CFI | Control-Flow Integrity — restricts indirect branches/returns to valid targets to thwart code‑reuse attacks (ROP/JOP). | LLVM/Clang CFI, Intel CET/IBT, ARM Pointer Authentication (PAC) harden control flow. |
CORS | Cross-Origin Resource Sharing — control cross-site requests. | Allow specific origins/headers. |
CSP | Content Security Policy — control resource loading; mitigate XSS. | default-src 'self' . |
CSRF | Cross-Site Request Forgery — unintended actions by a victim. | CSRF tokens, same-site cookies. |
CVE | Common Vulnerabilities and Exposures — public identifier for disclosed security issues. | CVE-2024-XXXXX referenced in advisories and patches. |
DAST | Dynamic App Security Testing — test running apps. | Zap/Burp scans. |
DDoS | Distributed Denial of Service — many-source DoS. | Botnet floods traffic. |
DKIM | DomainKeys Identified Mail — cryptographic email authentication using domain-signed headers. | Receivers verify DKIM-Signature with the sender's DNS key. |
DMARC | Domain-based Message Authentication, Reporting, and Conformance — email authentication policy leveraging SPF and DKIM with alignment and reporting. | Publish v=DMARC1; p=quarantine; rua=mailto:dmarc@example.com . |
DoS | Denial of Service — make a service unavailable. | Single-source flood. |
DRM | Digital Rights Management — technologies to control access, copying, and usage of digital content via encryption and licensing. | Browser EME with Widevine/PlayReady; app checks license server before playback. |
GPG | GNU Privacy Guard — OpenPGP implementation. | gpg --sign --encrypt file . |
HMAC | Hash-based Message Authentication Code — keyed hash for message integrity and authenticity. | HMAC‑SHA256 for API request signing; JWT HS256. |
HSM | Hardware Security Module — tamper‑resistant hardware appliance or cloud service for secure key generation, storage, and cryptographic operations with strong access controls and auditing. | Use an HSM/KMS to generate and store TLS/CA private keys; perform signing inside the module. |
HSTS | HTTP Strict Transport Security — force HTTPS for a period. | Strict-Transport-Security header. |
IAM | Identity and Access Management — users/roles/permissions. | Cloud IAM policies. |
IDS | Intrusion Detection System — monitors networks/hosts for malicious activity or policy violations, generating alerts for investigation. | Network IDS like Zeek/Snort; host IDS like OSSEC/Wazuh; alert to SIEM. |
IPS | Intrusion Prevention System — inline security control that inspects traffic/events and can automatically block or remediate detected threats. | IPS mode in next‑gen firewalls; Snort/Suricata inline dropping malicious packets. |
JWT | JSON Web Token — compact auth/claims token. | Authorization: Bearer <jwt> . |
MAC | Message Authentication Code — short, fixed-length tag produced from a message and secret key that enables verification of message integrity and authenticity. | Compute an AES-CMAC or HMAC-SHA256 over API payloads; receivers recompute the MAC to detect tampering. |
MDM | Mobile Device Management — administer and secure mobile/end-user devices via policies, enrollment, and remote actions. | Enforce passcodes, disk encryption, app whitelists; remote wipe on loss. |
MFA | Multi-Factor Authentication — 2+ factors. | Password + hardware key. |
MITM | Man-In-The-Middle — intercept/alter comms. | Rogue Wi-Fi AP sniffing. |
mTLS | Mutual TLS — both client and server present certificates. | Service-to-service auth in meshes. |
NX | No-eXecute bit — CPU feature that marks memory pages as non-executable to prevent code execution from data segments like the stack and heap. | OS sets the NX bit on the stack to mitigate buffer overflows; also known as DEP/XD/W^X. |
OAuth | Delegated authorization protocol. | Access token for API calls. |
OIDC | OpenID Connect — identity layer over OAuth 2.0. | ID token for login. |
OTP | One-Time Password — short‑lived code used for authentication; delivered or generated per login. | App‑generated TOTP/HOTP codes; avoid SMS OTP when possible. |
PGP | Pretty Good Privacy — encryption/signing format. | Email encryption/signing. |
PKCS | Public-Key Cryptography Standards — RSA-led standards defining formats and algorithms used in public-key crypto. | PKCS #1 (RSA), #7/CMS (cryptographic messages), #8 (private keys), #12 (PFX/P12), #5 (PBES), #10 (CSR). |
PKI | Public Key Infrastructure — system of CAs, certs, keys, and policies. | Issue and validate X.509 certs. |
PoLP | Principle of Least Privilege — grant only the minimum permissions necessary for a user or system to perform its function. | IAM roles with narrowly scoped permissions; run services as non-root users. |
RBAC | Role-Based Access Control — role-granted permissions. | Admin/Editor/Viewer roles. |
RCE | Remote Code Execution — run arbitrary code remotely. | Deserialization exploit. |
ROP | Return-Oriented Programming — code reuse attack that chains existing instruction sequences ("gadgets") ending in ret to execute arbitrary code, bypassing DEP/NX. | Chain ROP gadgets from loaded libraries to call mprotect and make the stack executable. |
RSA | Rivest–Shamir–Adleman — widely used public‑key cryptosystem for encryption and signatures. | 2048‑bit RSA keys; RSA‑PKCS#1 signatures; TLS certs. |
SAM | Security Accounts Manager — the database in Windows that stores user passwords (as hashes) and security principals. | The SAM file (%SystemRoot%/system32/config/SAM ); lsass.exe protects it. |
SAST | Static App Security Testing — analyze code/binaries. | SAST pipeline checks. |
SBOM | Software Bill of Materials — inventory of components, dependencies, and versions in software artifacts for transparency and vulnerability management. | Generate CycloneDX/SPDX SBOMs in CI; scan against CVEs. |
SFI | Software Fault Isolation — security technique that sandboxes untrusted code by rewriting its machine code to prevent it from accessing memory or calling functions outside its designated region. | Google Native Client (NaCl) uses SFI to safely run native code in the browser. |
SHA | Secure Hash Algorithm — family of cryptographic hash functions (SHA‑2/256/512; SHA‑3/Keccak). | TLS cert signatures, file integrity checks; Git moving from SHA‑1 to SHA‑256. |
SPF | Sender Policy Framework — DNS-based mechanism to authorize mail servers for a domain. | v=spf1 ip4:203.0.113.0/24 -all record. |
SQLi | SQL Injection — inject SQL via input. | Parameterized queries prevent it. |
SSH | Secure Shell — encrypted remote login/exec. | ssh user@host . |
SSO | Single Sign-On — authenticate once, access many apps. | SAML/OIDC-based SSO. |
SSRF | Server-Side Request Forgery — trick server to make requests. | Block metadata endpoints. |
TLS | Transport Layer Security — secure comms. | HTTPS uses TLS. |
TOTP | Time-Based One-Time Password — time-synced one-time codes. | Authenticator app 6-digit codes. |
XSRF | Alternate name for CSRF in some frameworks. | Angular XSRF-TOKEN cookie/header. |
XSS | Cross-Site Scripting — script injection into pages. | Output encoding, CSP. |
Legacy | ||
MD5 | Message Digest Algorithm 5 — legacy 128-bit cryptographic hash function; cryptographically broken (collisions) and unsuitable for security, but still used for checksums. | md5sum file.iso to verify integrity; avoid for passwords/signatures. |
NTLM | NT LAN Manager — a legacy Microsoft authentication protocol suite, superseded by Kerberos. | Windows workgroup authentication; fallback when Kerberos is unavailable. |
RACF | Resource Access Control Facility — the primary security system on IBM mainframes (z/OS), controlling access to datasets, applications, and system resources. | Define user profiles and grant dataset access with RACF commands. |
Historical | ||
SSL | Secure Sockets Layer — legacy to TLS. | Deprecated; use TLS. |
Privacy
Acronym | Meaning | Example |
---|---|---|
CCPA | California Consumer Privacy Act — US privacy law granting rights to access, delete, and opt out of sale of personal data. | Add Do Not Sell link; handle access/deletion requests. |
CPRA | California Privacy Rights Act — amends/expands CCPA with new rights (correction), sensitive data category, and the CPPA regulator. | Honor opt-out for sharing; handle sensitive PI with limits. |
DSAR | Data Subject Access Request — request by an individual to access, correct, delete, or obtain a copy of their personal data. | Process access/erasure/portability requests within statutory timelines. |
GDPR | General Data Protection Regulation — EU law governing personal data protection, rights, and obligations. | Lawful basis, DPO, DPIA; data subject rights (access/erasure/portability). |
HIPAA | Health Insurance Portability and Accountability Act — US law setting privacy/security standards for protected health information (PHI). | Covered entities sign BAAs; apply the HIPAA Privacy/Security Rules. |
PII | Personally Identifiable Information — data that can identify an individual; subject to privacy laws and safeguards. | Names, emails, SSNs; apply minimization, masking, and access controls. |
Infrastructure
Acronym | Meaning | Example |
---|---|---|
AD | Active Directory — Microsoft identity directory service. | Centralized auth/authorization. |
CDN | Content Delivery Network — globally distributed cache. | Faster static asset delivery. |
DNS | Domain Name System — resolve names to IPs. | A , AAAA , CNAME records. |
DNSSEC | Domain Name System Security Extensions — adds origin authentication and data integrity to DNS using digital signatures (RRSIG) validated via a chain of trust from signed zones and DS records. | Sign zones with ZSK/KSK; validators check RRSIGs and DS chain from the root; prevents cache poisoning/spoofing. |
FaaS | Function as a Service — serverless functions. | AWS Lambda handlers. |
FQDN | Fully Qualified Domain Name — complete, absolute domain name that specifies all labels up to the root. | host1.db.eu-west.example.com. (trailing dot optional in practice). |
HPC | High-Performance Computing — parallel, large-scale compute using clusters/supercomputers for scientific/engineering workloads. | Run MPI/Slurm jobs on a GPU/CPU cluster with InfiniBand. |
IaaS | Infrastructure as a Service — virtual compute/storage/network. | EC2/Compute Engine. |
IaC | Infrastructure as Code — manage infrastructure with code and VCS. | Use Terraform to provision cloud resources via PRs. |
IoT | Internet of Things — networked embedded devices and sensors that collect data and interact with the physical world. | MQTT devices sending telemetry to an IoT hub. |
K8S | Kubernetes — container orchestration. | kubectl get pods . |
KMS | Key Management Service — managed key storage and cryptographic operations. | AWS KMS for envelope encryption and key rotation. |
KVM | Kernel-based Virtual Machine — Linux kernel virtualization enabling VMs with hardware acceleration via KVM modules. | Run QEMU with KVM for near-native performance; manage with libvirt/virt-manager. |
LB | Load Balancer — distributes traffic across multiple backends for scalability and resilience. | AWS ALB/NLB, HAProxy/Nginx with health checks and stickiness. |
LXC | Linux Containers — OS-level virtualization using cgroups/namespaces to isolate processes. | Run lightweight containers without a separate kernel per instance. |
MPI | Message Passing Interface — standardized API for distributed-memory parallel programming using processes that communicate via messages. | Launch ranks with mpirun (OpenMPI/MPICH); use collectives like MPI_Bcast /MPI_Reduce . |
NAS | Network-Attached Storage — dedicated file storage accessible over a network. | Home/SMB NAS appliances exposing NFS/SMB shares. |
OCI | Open Container Initiative — specs for container images and runtimes. | OCI Image format and OCI Runtime (runc). |
PaaS | Platform as a Service — deploy apps without infra mgmt. | Heroku, App Engine. |
QEMU | Quick EMUlator — open-source machine emulator and virtualizer supporting full-system emulation and hardware-accelerated virtualization across many architectures. | Boot ARM or RISC-V guests with qemu-system-* ; pair with KVM for x86 virtualization on Linux hosts. |
SaaS | Software as a Service — subscription-based software. | Hosted CRM/Email. |
SAN | Storage Area Network — high-speed network providing block-level storage access to servers. | Fibre Channel/iSCSI SAN for shared volumes. |
SIMH | Simulator for Historical Computers — open-source emulator suite for classic minicomputers/mainframes (PDP-11, VAX, IBM 1401, etc.), preserving vintage software environments. | Boot a PDP-11 running RT-11/RSX or a VAX/VMS system image for retrocomputing and software archaeology. |
TCG | Tiny Code Generator — QEMU's dynamic binary translation engine that recompiles guest CPU instructions into host machine code at runtime when hardware acceleration isn't available. | Run QEMU in pure emulation mode; TCG translates ARM guest opcodes to x86 host instructions on the fly. |
UPS | Uninterruptible Power Supply — device providing battery-backed power to keep equipment running through short outages and allow graceful shutdown. | Rack UPS for servers/network gear; runtime and VA/W ratings. |
VM | Virtual Machine — emulated hardware environment to run OS instances. | KVM/Hyper-V VMs for isolation. |
VPC | Virtual Private Cloud — isolated virtual network. | Subnets, route tables, SGs. |
VPN | Virtual Private Network — secure tunnel. | Site-to-site/client VPN. |
Hardware (Architecture)
Acronym | Meaning | Example |
---|---|---|
AMD64 | 64-bit x86 architecture introduced by AMD (aka x86-64, adopted by Intel as Intel 64) extending IA-32 with 64-bit registers, more general-purpose registers, and long mode. | Build for x86_64 /amd64 ; Linux System V AMD64 ABI; Windows x64 with WOW64 for 32-bit apps. |
ARM | Advanced RISC Machines — 32-bit RISC architecture (AArch32) originating from Acorn, spanning ARMv1-v7 cores widely used in mobile, embedded, and microcontroller systems. | Cross-compile for armv7 /armhf ; run 32-bit ARM Linux on Raspberry Pi models or Cortex-M firmware. |
ARM64 | 64-bit ARM architecture (aka AArch64, ARMv8-A and later) with a new instruction set and execution state distinct from 32-bit ARM (AArch32). | Build for arm64 /aarch64 ; Apple Silicon Macs, AWS Graviton/Neoverse servers, Android flagship SoCs. |
ASIC | Application-Specific Integrated Circuit — a chip customized for a particular use, rather than for general-purpose use like a CPU. | Bitcoin mining ASICs; Google TPU for machine learning. |
CHERI | Capability Hardware Enhanced RISC Instructions — architectural extensions that add tagged, unforgeable capabilities to enforce fine‑grained memory safety and compartmentalization. | CHERI‑RISC‑V/MIPS; pointers carry bounds/permissions; safer C/C++ and sandboxing. |
CISC | Complex Instruction Set Computer — CPU design approach featuring larger, more complex, and variable‑length instructions, often implemented with microcode. | x86/x86‑64 architectures; REP MOVS , string ops, rich addressing modes. |
CUDA | Compute Unified Device Architecture — NVIDIA's parallel computing platform and programming model for GPUs. | Launch kernels in CUDA C++; PyTorch/TensorFlow GPU ops. |
EM64T | Extended Memory 64 Technology — Intel’s original branding for its AMD64‑compatible 64‑bit x86 implementation, now marketed as Intel 64. | Intel Core/Xeon CPUs report Intel 64; target x86_64 in toolchains. |
IA-32 | 32‑bit Intel architecture — the classic 32‑bit x86 ISA (i386 and successors) with protected mode, paging, and SSE-era extensions; predecessor to x86‑64. | Build for x86 /i386 /i686 ; 32‑bit OSes/apps, WOW64 on Windows x64, multilib on Linux. |
ISA | Instruction Set Architecture — contract describing a CPU’s instructions, registers, memory model, and privilege levels; distinct from microarchitecture. | x86‑64, ARMv8‑A; RISC‑V RV64GC with optional extensions. |
MIPS | Microprocessor without Interlocked Pipeline Stages — classic RISC architecture used in embedded systems, networking gear, and historically in workstations/servers. | MIPS32/MIPS64 in routers and embedded devices; historical SGI workstations/IRIX. |
NUMA | Non-Uniform Memory Access — architecture where memory access latency and bandwidth vary depending on whether memory is local to a CPU socket/node or remote. | Pin threads and allocate memory per NUMA node (e.g., numactl ) to reduce cross-socket traffic. |
PA-RISC | Precision Architecture RISC — Hewlett‑Packard’s RISC architecture used in HP 9000 servers/workstations, largely superseded by Itanium and then x86‑64. | HP‑UX on PA‑RISC systems (e.g., PA‑8700/8900); historical HP 9000 platforms. |
POWER | IBM Performance Optimization With Enhanced RISC — IBM’s RISC architecture family used in servers/workstations (POWER4+), distinct but related to the PowerPC lineage. | IBM Power Systems running AIX/IBM i/Linux; POWER9/POWER10 CPUs. |
PPC | PowerPC — RISC CPU architecture developed by the AIM alliance (Apple–IBM–Motorola), used in desktops historically and widely in embedded/console systems. | PowerPC 32/64‑bit (POWER/PowerPC); GameCube/Wii/PS3; embedded/controllers. |
RISC | Reduced Instruction Set Computer — CPU design philosophy emphasizing a small, simple instruction set and efficient pipelines. | ARM and RISC-V architectures. |
RISC-V | Open standard RISC instruction set architecture with modular extensions (e.g., I/M/A/F/D/V) and 32/64/128‑bit variants (RV32/64/128); free to implement without licensing. | Microcontrollers to servers; Linux on RV64GC; chips from SiFive, Andes; SBCs and accelerators. |
SMP | Symmetric Multiprocessing — architecture where multiple identical CPUs/cores share the same memory and OS, enabling parallel execution of threads/processes. | Multi-core x86/ARM systems; OS scheduler runs threads across cores with shared memory. |
SPARC | Scalable Processor ARChitecture — RISC CPU architecture originally developed by Sun Microsystems, widely used in servers/workstations and embedded systems. | SPARC V8/V9 (32/64‑bit); UltraSPARC/Oracle SPARC running Solaris/illumos. |
X86-64 | Generic name for the 64‑bit x86 ISA (defined by AMD as AMD64 and implemented by Intel as Intel 64/EM64T); adds 64‑bit mode and more registers over IA‑32. | Build for x86_64 ; 64‑bit OSes and apps on AMD/Intel processors. |
Historical | ||
AT | Advanced Technology — the IBM PC/AT was the successor to the XT, introducing the 16-bit ISA bus, the 286 processor, and the AT keyboard connector. | The AT form factor and motherboard design influenced PCs for years. |
CD-i | Compact Disc Interactive — a multimedia CD player and platform developed by Philips and Sony. | Known for its games and educational titles in the early 1990s. |
IA-64 | Intel Itanium architecture — 64‑bit EPIC (Explicitly Parallel Instruction Computing) ISA developed by Intel/HP; distinct from x86/x86‑64 and now discontinued. | Itanium servers/workstations running HP‑UX, OpenVMS, and legacy Windows Server for Itanium‑based systems. |
MSX | Machines with Software eXchangeability — a standardized home computer architecture from the 1980s. | Popular in Japan and Europe; Konami games on MSX. |
PDP | Programmed Data Processor — DEC minicomputer line before VAX. | PDP‑8, PDP‑11 systems. |
VAX | Virtual Address eXtension — DEC 32‑bit minicomputer architecture. | VAX/VMS systems in universities and industry. |
XT | Extended Technology — the IBM PC XT was an early version of the PC that included a hard drive. | The 8-bit bus architecture of the PC/XT. |
Hardware (CPU / General)
Acronym | Meaning | Example |
---|---|---|
ALU | Arithmetic Logic Unit — digital circuit in the CPU that performs integer arithmetic and bitwise operations. | Add, subtract, AND/OR/XOR, shifts/rotates executed by the ALU pipelines. |
AP | Application Processor — any non‑bootstrap CPU core in an SMP system that is brought online by the BSP to run the OS scheduler and workloads. | OS sends INIT/SIPI to start APs after BSP init; threads scheduled across APs. |
BSP | Bootstrap Processor — on multi-processor systems (e.g., x86 SMP), the primary CPU core that starts executing firmware/boot code and brings up the OS, which then initializes the remaining cores as Application Processors (APs). | Firmware runs on the BSP first; OS sends INIT/SIPI to start APs. |
CPU | Central Processing Unit — main processor that executes instructions. | x86-64 CPUs with multiple cores/threads and SIMD. |
FPU | Floating Point Unit — hardware for floating-point arithmetic. | IEEE 754 operations, SIMD extensions. |
L1/L2/L3 | Level 1/2/3 Cache — hierarchical caches in a CPU that store frequently accessed data to reduce latency to main memory. | L1 is fastest/smallest (per-core I/D); L2 is larger (per-core); L3 is largest (shared). |
MMU | Memory Management Unit — hardware for virtual memory and address translation. | x86-64 paging with TLBs. |
NMI | Non-Maskable Interrupt — high-priority hardware interrupt that cannot be disabled by normal interrupt masking, used for critical fault or watchdog conditions. | Watchdog parity/ECC errors trigger NMI; OS NMI handler logs/diagnoses hangs. |
SIMD | Single Instruction, Multiple Data — vector parallelism executing the same instruction across multiple data lanes. | SSE/AVX on x86, NEON on ARM. |
TLB | Translation Lookaside Buffer — small cache of virtual→physical address translations used by the MMU. | TLB hits speed up paging; TLB flush on context switch. |
Hardware (CPU / ARM)
Acronym | Meaning | Example |
---|---|---|
EL0/1/2/3 | Exception Levels — ARMv8 privilege levels: EL0 (unprivileged), EL1 (OS kernel), EL2 (hypervisor), EL3 (secure monitor). | User apps run at EL0; the kernel at EL1; KVM at EL2. |
GIC | Generic Interrupt Controller — standard ARM architecture for managing interrupts, routing them from peripherals to CPU cores. | GICv2/v3/v4; the ARM equivalent of x86's APIC. |
NEON | ARM's advanced SIMD (Single Instruction, Multiple Data) architecture extension for accelerating multimedia and signal processing. | NEON intrinsics for video encoding; equivalent to x86 SSE/AVX. |
SVE | Scalable Vector Extension — next-generation SIMD instruction set for ARM AArch64, designed for HPC with vector-length agnostic programming. | High-performance computing workloads on ARM servers. |
Hardware (CPU / x86)
Acronym | Meaning | Example |
---|---|---|
AMX | Advanced Matrix Extensions — x86 instruction set extensions providing tiled matrix operations accelerated in hardware. | Intel AMX for deep‑learning inference/training (tile registers, TMUL). |
APIC | Advanced Programmable Interrupt Controller — modern local/IO APICs providing scalable interrupt delivery in SMP systems. | LAPIC per core and IOAPIC for external IRQs on x86. |
AVX | Advanced Vector Extensions — x86 SIMD instruction set extensions for wide vector operations (256/512-bit in AVX/AVX-512). | AVX2 for integer ops; AVX-512 for HPC workloads. |
SSE | Streaming SIMD Extensions — x86 SIMD instruction set extensions for parallel vector operations. | SSE2/SSE4 intrinsics; compiler autovectorization for math/graphics. |
VMX | Virtual Machine Extensions — Intel x86 virtualization extensions (VT‑x) that add CPU modes/instructions (VMX root/non‑root, VMXON/VMXOFF, VMLAUNCH/VMRESUME) and a VMCS for hardware‑assisted virtualization. | Enable VT‑x in firmware; KVM/Hyper‑V/VMware use VMX to run guests with hardware assist. |
xAPIC | Extended APIC — the default operational mode for the modern x86 APIC, using MMIO for register access. | The OS maps the LAPIC's MMIO region to send IPIs and manage local interrupts. |
Historical | ||
MMX | MultiMedia eXtensions — early x86 SIMD instruction set for integer vector operations. | Legacy MMX ops predating SSE on Pentium-era CPUs. |
Hardware (Memory)
Acronym | Meaning | Example |
---|---|---|
DDR | Double Data Rate — class of synchronous DRAM that transfers data on both clock edges for higher bandwidth. | DDR4/DDR5 SDRAM in modern systems. |
DIMM | Dual Inline Memory Module — standardized memory module form factor for SDRAM. | 288‑pin DDR4/DDR5 DIMMs. |
DRAM | Dynamic Random Access Memory — volatile memory storing bits in capacitors that require periodic refresh. | Main system memory (SDRAM/DDR). |
ECC | Error-Correcting Code memory — memory modules/chipsets that detect and correct single‑bit errors (and detect some multi‑bit errors) to improve reliability. | ECC UDIMMs/RDIMMs in servers/workstations; machine check logs corrected errors. |
EEPROM | Electrically Erasable Programmable Read-Only Memory — non-volatile memory that can be electrically erased and reprogrammed at the byte/page level; used for small configuration storage and microcontroller data. | I²C/SPI EEPROMs (24xx/25xx series); MCU calibration data; distinct from flash (block erase). |
GDDR | Graphics Double Data Rate — high‑bandwidth memory variants optimized for GPUs and graphics workloads. | GDDR6/GDDR6X on modern GPUs; wide buses and high data rates. |
HBM | High Bandwidth Memory — stacked memory connected via wide interfaces on‑package for very high bandwidth and energy efficiency. | HBM2/HBM3 on AI/ML accelerators and high‑end GPUs. |
LPDDR | Low-Power DDR — mobile/embedded DRAM optimized for low power with deep power states and wide IO at low voltage. | LPDDR4/4X/5/5X in smartphones, tablets, ultrabooks, and SoCs. |
NVRAM | Non-Volatile RAM — memory that retains data without power; implemented via flash, EEPROM, or battery‑backed SRAM; often stores firmware variables/settings. | UEFI variables in NVRAM; macOS NVRAM for boot args and device settings. |
RAM | Random Access Memory — volatile memory used for working data and code. | DDR4/DDR5 DIMMs. |
ROM | Read-Only Memory — non-volatile memory storing firmware or static data. | Boot ROM, option ROMs. |
SDRAM | Synchronous Dynamic Random Access Memory — DRAM synchronized with the system clock, enabling pipelined access and higher throughput versus asynchronous DRAM. | PC100/PC133 SDRAM; basis for modern DDR (DDR/DDR2/3/4/5). |
SO-DIMM | Small Outline Dual Inline Memory Module — compact memory module form factor used in laptops and small form-factor systems; electrically similar to DIMMs but physically smaller and not interchangeable. | DDR4/DDR5 SO‑DIMMs in laptops/NUCs; shorter modules with different keying. |
SRAM | Static Random Access Memory — volatile memory using flip-flops; fast and does not need refresh. | CPU caches (L1/L2/L3) implemented with SRAM. |
Historical | ||
EDO | Extended Data Out DRAM — improved asynchronous DRAM that allows the data output to remain valid longer, enabling slightly higher performance than FPM before SDRAM became mainstream. | Mid‑1990s 486/Pentium systems with EDO SIMMs; replaced by SDRAM. |
EPROM | Erasable Programmable Read-Only Memory — UV-erasable ROM chips with a quartz window; erased under UV light and reprogrammed with a programmer. | 27xx-series EPROMs in retro computers/arcade boards; UV eraser tools. |
FPM | Fast Page Mode DRAM — asynchronous DRAM access mode that speeds up accesses within the same row/page compared to plain DRAM; predecessor to EDO and SDRAM. | Early 1990s SIMM modules using FPM; superseded by EDO/SDRAM. |
PROM | Programmable Read-Only Memory — one-time programmable ROM that can be programmed once after manufacturing and cannot be erased. | 82S/27S series PROMs used for microcode/firmware; fuse/antifuse technologies. |
RDRAM | Rambus DRAM — high‑bandwidth DRAM technology from Rambus used with RIMM modules and a packetized, narrow bus; briefly mainstream on Pentium 4 before being displaced by DDR SDRAM. | RIMM modules in Intel i850/i850E chipsets; now obsolete in favor of DDR/DDR2+. |
RIMM | Rambus Inline Memory Module — module form factor for RDRAM with continuity requirements (CRIMMs in empty slots) and heat spreaders; used briefly in early‑2000s PCs/servers. | Populate paired RIMMs on i850 boards; install CRIMMs in unused slots; now obsolete. |
SIMM | Single Inline Memory Module — older memory module form factor with a single set of contacts; used with FPM/EDO/early SDRAM. | 30‑pin/72‑pin SIMMs on 386/486/Pentium-era systems. |
Hardware (Buses & Interfaces)
Acronym | Meaning | Example |
---|---|---|
AHB | Advanced High-performance Bus — an AMBA bus protocol for connecting lower-performance peripherals. | Part of the on-chip bus fabric in an ARM SoC. |
AMBA | Advanced Microcontroller Bus Architecture — a family of on-chip interconnect specifications for connecting functional blocks in an SoC. | AMBA protocols include AXI, AHB, and APB. |
APB | Advanced Peripheral Bus — a low-bandwidth AMBA bus protocol for simple peripherals. | Connecting UARTs, GPIO, and timers in an SoC. |
AXI | Advanced eXtensible Interface — a high-performance AMBA bus protocol for demanding components like CPUs, GPUs, and memory controllers. | The main high-speed bus in a modern ARM SoC. |
CCIX | Cache Coherent Interconnect for Accelerators — an industry standard for coherent interconnects between processors and accelerators. | Connecting FPGAs or GPUs to an ARM server CPU. |
CMN | Coherent Mesh Network — ARM's high-performance mesh interconnect for connecting components within an SoC and between multiple SoCs. | The socket-to-socket interconnect in multi-socket ARM servers. |
DMI | Direct Media Interface — Intel's proprietary link between a CPU and the Platform Controller Hub (PCH). | DMI 3.0/4.0 providing bandwidth for peripherals connected to the PCH. |
GPIO | General-Purpose Input/Output — configurable digital pins on microcontrollers/SoCs used for reading inputs and driving outputs; often support pull‑ups/downs and interrupts. | Toggle Raspberry Pi GPIO with libgpiod ; configure pin mode and edge interrupts. |
HBA | Host Bus Adapter — adapter that connects a host system to storage or network devices over a high‑speed bus/fabric (e.g., SAS, Fibre Channel). | FC/SAS HBAs in servers to attach SAN/storage arrays; visible via lspci . |
HCI | Host Controller Interface — standardized command/event interface between a host stack and a hardware controller (notably in Bluetooth; also USB xHCI). | Capture Bluetooth HCI packets with btmon ; interact via UART/USB HCI. |
I2C | Inter-Integrated Circuit — a synchronous, multi-controller, multi-peripheral serial bus used for attaching low-speed peripherals to a motherboard or embedded system. | Connect sensors/EEPROMs to a microcontroller (SDA/SCL lines). |
JTAG | Joint Test Action Group — industry standard for on-chip debugging, programming, and testing of integrated circuits. | Use a JTAG debugger to halt a CPU, inspect registers, and flash firmware. |
MIDI | Musical Instrument Digital Interface — standard protocol/interface for transmitting musical performance data between instruments, controllers, and computers. | 5‑pin DIN or USB‑MIDI; Note On/Off, Control Change; DAW controlling a synth. |
PCI | Peripheral Component Interconnect — hardware bus standard for attaching peripherals. | PCI devices enumerated by bus/device/function. |
PCIe | PCI Express — high-speed serial successor to PCI with lanes and links. | x16 GPU slot; NVMe drives over PCIe. |
PS/2 | Personal System/2 — legacy Mini‑DIN interface for keyboards and mice on PCs. | PS/2 keyboard/mouse ports on motherboards/KVMs; supports NKRO without USB polling. |
SPI | Serial Peripheral Interface — synchronous serial bus with master/slave (controller/peripheral) and separate data lines for full-duplex transfers. | Connect sensors/flash to microcontrollers (MOSI/MISO/SCLK/CS); higher speed than I²C. |
UART | Universal Asynchronous Receiver-Transmitter — hardware for serial communication using asynchronous framing (start/stop bits) over TTL/RS-232 levels. | Debug console on microcontrollers; /dev/ttyS* //dev/ttyUSB* ; 115200 8N1. |
UPI | Ultra Path Interconnect — Intel's current point-to-point processor interconnect for server CPUs, successor to QPI. | High-speed link between sockets on multi-processor Xeon systems. |
USB | Universal Serial Bus — standard for cables and connectors between computers and peripherals. | USB 3.x devices; HID, storage, and serial classes. |
Legacy | ||
COM | Serial COM port — PC designation for RS‑232 serial interfaces (COM1/COM2/...), typically provided by 16550‑class UARTs on DB‑9 connectors. | Connect via null‑modem/USB‑serial; Windows COM3: ; Linux /dev/ttyS0 serial consoles. |
LPC | Low Pin Count — a bus used on PC-compatible motherboards to connect low-bandwidth devices to the southbridge. | Connects the Super I/O chip, BIOS ROM, and TPM. |
QPI | QuickPath Interconnect — Intel's point-to-point processor interconnect that replaced the FSB; superseded by UPI. | High-speed link between CPU and I/O hub on Nehalem/Sandy Bridge-E systems. |
Historical | ||
EISA | Extended Industry Standard Architecture — 32‑bit ISA-compatible bus developed by a consortium as an open alternative to MCA; supported bus mastering and IRQ sharing. | Server‑class 486 systems with EISA expansion cards; later replaced by PCI. |
FSB | Front-Side Bus — the main interface between the CPU and the northbridge in older PC architectures, superseded by on-chip memory controllers and point-to-point interconnects. | Pentium 4 on an 800MHz FSB; overclocking by raising the FSB speed. |
ISA | Industry Standard Architecture — legacy 8/16‑bit PC expansion bus. | Sound/IO cards on 286/386 era PCs. |
LPT | Line Printer port — PC parallel printer interface (Centronics/IEEE 1284), addressed as LPT1/LPT2; largely obsolete. | Parallel printers and hardware dongles; DB‑25 connectors; IEEE 1284 SPP/EPP/ECP modes. |
MCA | Micro Channel Architecture — IBM's proprietary 32‑bit bus introduced with PS/2 systems as a successor to ISA; offered bus mastering and improved throughput but lacked industry adoption. | IBM PS/2 expansion cards; supplanted by EISA/PCI. |
PCMCIA | Personal Computer Memory Card International Association — the standard for laptop expansion cards (e.g., modems, network cards) before USB and ExpressCard. | Also known as PC Card; Type I/II/III cards. |
Q-BUS | DEC Q‑bus — asynchronous multiplexed address/data bus used in later PDP‑11 and early MicroVAX systems; lower-cost successor to Unibus with fewer signals. | Q‑bus backplanes/peripherals in PDP‑11/23 and MicroVAX; legacy DEC minicomputers. |
Unibus | DEC Unibus — early synchronous shared backplane bus interconnecting CPU, memory, and peripherals in PDP‑11 systems; predecessor to Q‑bus. | PDP‑11 Unibus backplanes/peripherals; historical DEC minicomputers. |
VLB | VESA Local Bus — high‑speed local bus before PCI. | 486 motherboards with VLB video/IO cards. |
VME | VMEbus (Versa Module Europa) — parallel backplane bus standard (IEEE 1014) widely used in embedded/industrial systems with Eurocard form factors (3U/6U) and modular CPU/I/O cards. | VME chassis in telecom, industrial control, and defense; CPU cards and I/O modules on a shared backplane. |
Hardware (Storage)
Acronym | Meaning | Example |
---|---|---|
AHCI | Advanced Host Controller Interface — standard programming interface for SATA host controllers enabling features like NCQ, hot-plug, and native command queuing. | OS uses the AHCI driver; set SATA mode to AHCI in firmware for modern OS installs. |
GPT | GUID Partition Table — modern disk partitioning scheme that supports large disks and many partitions, part of the UEFI standard. | Disks initialized with GPT instead of legacy MBR. |
HDD | Hard Disk Drive — magnetic storage device with spinning platters and moving heads. | 3.5"/2.5" SATA HDDs for bulk storage; higher latency than SSDs. |
LBA | Logical Block Addressing — linear addressing scheme for block devices that replaces legacy CHS (Cylinder/Head/Sector) geometry. | 512‑byte/4K sectors addressed by LBA; used by SATA/SCSI/NVMe. |
LTO | Linear Tape-Open — open tape storage format for data backup/archive with generational roadmap (LTO‑1..LTO‑9), high capacity, and LTFS support. | LTO‑8/LTO‑9 tape drives/libraries in enterprise backups; use LTFS for file‑like access. |
LUN | Logical Unit Number — identifier addressing a logical unit (virtual disk) within a SCSI/iSCSI/Fibre Channel target, used for mapping storage to hosts. | Present LUNs from a SAN array to servers; host multipath to the same LUN. |
NCQ | Native Command Queuing — SATA feature allowing a drive to accept and reorder multiple outstanding requests to optimize head movement and throughput. | AHCI/SATA HDDs/SSDs improving random I/O by reordering commands. |
NVMe | Non-Volatile Memory Express — interface protocol for SSDs over PCIe. | M.2 NVMe SSD with high IOPS/low latency. |
RAID | Redundant Array of Independent Disks — combine multiple drives for redundancy and/or performance. | RAID 1 mirroring; RAID 5 parity; RAID 10 stripe+mirror. |
SAS | Serial Attached SCSI — point‑to‑point serial interface for enterprise storage. | 12Gb/s SAS HDDs/SSDs; SAS expanders/backplanes. |
SATA | Serial ATA — interface for connecting storage devices. | 2.5" SATA SSDs and HDDs. |
SD | Secure Digital — flash memory card format with variants (SD/SDHC/SDXC) commonly used in portable devices; typically formatted with FAT32 or exFAT. | Cameras, handheld consoles, and phones; microSD cards with adapters. |
SMART | Self-Monitoring, Analysis and Reporting Technology — monitoring system in disk drives to detect and report on indicators of drive reliability. | smartctl to read SMART data and predict drive failure. |
SSD | Solid-State Drive — storage device using flash memory (no moving parts), offering low latency and high throughput. | NVMe SSDs for fast boot and build times. |
Legacy | ||
EIDE | Enhanced IDE — extensions to IDE/PATA. | Support for larger drives and ATAPI. |
IDE/PATA | Integrated Drive Electronics / Parallel ATA — legacy parallel disk interface. | 40/80‑wire ribbon cables for HDD/optical drives. |
MBR | Master Boot Record — legacy partitioning scheme and first 512 bytes of a disk containing boot code and a partition table. | BIOS boots from MBR; up to 4 primary partitions or extended/logical. |
UDMA | Ultra Direct Memory Access — ATA/IDE DMA transfer modes providing higher throughput and lower CPU usage than PIO; modes UDMA/33/66/100/133 (higher modes require 80‑wire cables). | PATA drive negotiates UDMA/5 (ATA/100); Linux dmesg shows UDMA/133. |
WORM | Write Once, Read Many — non‑rewritable archival storage media. | Optical WORM jukeboxes for compliance archives. |
Historical | ||
CHS | Cylinder/Head/Sector — legacy disk geometry addressing scheme used by BIOS/MBR era systems; limited capacity and translation quirks. | 1024‑cylinder limit; CHS/LBA translation in BIOS; superseded by LBA. |
DDS | Digital Data Storage — magnetic tape data storage format derived from DAT (Digital Audio Tape), widely used for backups in the 1990s–2000s (DDS‑1..4, DDS‑DC, DAT72). | DAT/DDS tape drives and media for server/workstation backups; largely obsolete today. |
DLT | Digital Linear Tape — half‑inch magnetic tape storage format popular in the 1990s–2000s for enterprise backups; superseded by LTO. | DLT/SDLT drives and media in tape libraries; largely obsolete now. |
FDD | Floppy Disk Drive — magnetic removable storage. | 5.25" and 3.5" floppies. |
MFM | Modified Frequency Modulation — legacy disk encoding scheme. | Early HDDs and floppies using MFM/RLL. |
QIC | Quarter-Inch Cartridge — magnetic tape data storage format using 1/4" tape in cartridges; common for backups on PCs/workstations in the 1980s–1990s (e.g., QIC-80/150, Travan). | Tape backup drives and cartridges; largely obsolete today. |
RLL | Run Length Limited — denser successor to MFM for magnetic storage. | RLL controllers for higher HDD capacity. |
SCSI | Small Computer System Interface — parallel peripheral bus widely used pre‑SATA/USB. | External SCSI disks and scanners on workstations. |
Hardware (Video & Displays)
Acronym | Meaning | Example |
---|---|---|
DP | DisplayPort — digital display interface with high bandwidth, daisy‑chaining via MST, and adaptive sync support. | DP 1.4/2.0 to high‑refresh monitors; USB‑C DP Alt Mode; MST hub. |
DPI | Dots Per Inch — measure of print/display resolution; colloquially used for screens though PPI is more precise. | 300‑DPI print quality; “Retina” displays around ~220 PPI. |
EDID | Extended Display Identification Data — data structure provided by a display to describe its capabilities (e.g., resolution, timings) to a video source. | GPU reads monitor's EDID over DDC to configure the display mode. |
GPU | Graphics Processing Unit — highly parallel processor optimized for graphics and compute. | CUDA/OpenCL workloads; 3D rendering. |
HD | High Definition — 720p (1280×720) and 1080i/p (1920×1080) resolution classes. | 1080p monitor; HD streaming. |
HDCP | High-bandwidth Digital Content Protection — copy protection scheme to prevent copying of digital audio/video content as it travels across connections. | HDMI/DisplayPort connections requiring HDCP for protected content playback. |
HDMI | High-Definition Multimedia Interface — digital audio/video interface for connecting sources to displays. | HDMI 2.0/2.1 to monitors/TVs; HDCP for protected content. |
LCD | Liquid Crystal Display — flat‑panel display technology that uses liquid crystals modulated by a backlight to produce images. | IPS/TN/VA LCD panels; requires LED backlight. |
LED | Light‑Emitting Diode — semiconductor light source; in monitors/TVs, often shorthand for LED‑backlit LCDs (not emissive per‑pixel). | Status indicator LEDs; LED‑backlit LCD monitors/TVs. |
OLED | Organic Light‑Emitting Diode — emissive display technology where each pixel emits light for high contrast and true blacks. | AMOLED smartphone screens; per‑pixel dimming on TVs/phones. |
PPI | Pixels Per Inch — measure of display pixel density; often confused with DPI which is for print. | 326‑PPI phone display; ~220‑PPI “Retina” laptop panels. |
QHD | Quad High Definition — 2560×1440 (1440p) resolution at 16:9; roughly 4× 720p and about half the pixels of 4K UHD. | 27" 1440p monitors; competitive gaming displays. |
RGB | Red, Green, Blue — additive color model used in displays and imaging. | sRGB color space; RGB LED subpixels in LCD/OLED panels. |
RGBA | Red, Green, Blue, Alpha — RGB color with an additional alpha (opacity) channel for transparency. | CSS rgba(255, 0, 0, 0.5) ; PNG images with alpha channel. |
UHD | Ultra High Definition — 4K UHD (3840×2160) consumer resolution class; sometimes extends to 8K (7680×4320). | 4K 2160p TV/monitor; UHD streaming. |
VESA | Video Electronics Standards Association — industry group that defines and maintains display and related interface standards. | DisplayHDR, DP standards, EDID/DMT timing standards. |
VRAM | Video RAM — memory used by GPUs/display controllers to store framebuffers, textures, and render targets; historically specialized types (e.g., SGRAM, GDDR). | Dedicated GDDR6 on discrete GPUs; shared system memory on iGPUs. |
Legacy | ||
SD | Standard Definition — legacy video resolution class around 480i/480p (NTSC) or 576i/576p (PAL), typically 4:3 aspect. | DVD 480p; SDTV broadcast. |
SVGA | Super VGA — VESA extensions beyond VGA. | 800×600 and higher resolutions. |
VGA | Video Graphics Array — de facto PC graphics standard. | 640×480 16‑color; mode 13h 320×200×256. |
Historical | ||
AGP | Accelerated Graphics Port — dedicated graphics slot pre‑PCIe. | AGP 4×/8× graphics cards. |
CGA | Color Graphics Adapter — IBM PC color graphics standard. | 320×200 4‑color modes on early PCs. |
CRT | Cathode Ray Tube — vacuum tube display technology that steers electron beams across a phosphor‑coated screen to form images. | Legacy CRT monitors/TVs; scanlines, phosphor persistence, high refresh at lower resolutions. |
EGA | Enhanced Graphics Adapter — improved IBM graphics adapter. | 640×350 16‑color graphics. |
MDA | Monochrome Display Adapter — the original text-only video card for the IBM PC. | 80x25 character mode with a green or amber phosphor monitor. |
Hardware (General)
Acronym | Meaning | Example |
---|---|---|
ATX | Advanced Technology eXtended — PC motherboard and power supply form factor standard defining board sizes, mounting, I/O shield, and power connectors. | ATX/mATX/ITX cases; 24‑pin ATX, 8‑pin EPS12V, PCIe 6/8‑pin/12VHPWR. |
CMOS | Complementary Metal‑Oxide‑Semiconductor — low‑power technology used for chips; in PCs, also refers to the small battery‑backed RAM storing firmware settings. | Replace CMOS battery; clear CMOS to reset BIOS/UEFI settings. |
DMA | Direct Memory Access — device-initiated memory transfers without CPU involvement. | NICs use DMA for packet buffers. |
FPGA | Field-Programmable Gate Array — reconfigurable semiconductor device consisting of programmable logic blocks and interconnects configured by a bitstream to implement custom digital circuits. | Prototype/accelerate designs; soft CPUs and hardware offload over PCIe; tools like Vivado/Quartus using HDL/RTL. |
HID | Human Interface Device — USB device class for human input/output peripherals using structured HID reports. | USB keyboards, mice, gamepads; HID report descriptors parsed by OS. |
HPET | High Precision Event Timer — modern hardware timer with multiple high-resolution counters/comparators, providing precise periodic interrupts and timestamps that supersede legacy PIT/RTC timers in PCs. | Program HPET registers via MMIO to drive scheduler ticks, high-resolution timers, or multimedia clocks with microsecond accuracy. |
IRQ | Interrupt Request — a hardware signal line used by devices to interrupt the CPU for service. | Timer, keyboard, NIC raise IRQs; OS dispatches to ISRs. |
KVM | Keyboard–Video–Mouse switch — hardware device to control multiple computers with a single keyboard, monitor, and mouse. | Toggle between two PCs with a USB/HDMI KVM switch. |
MMIO | Memory-Mapped I/O — device registers mapped into the CPU address space for control/status. | Writing to MMIO addresses to control PCIe device registers. |
NIC | Network Interface Controller — hardware that connects a computer to a network. | Ethernet adapters; 10/25/40/100GbE NICs with offloads. |
OEM | Original Equipment Manufacturer — company that produces components or products that are marketed by another company; also denotes vendor‑specific builds/licenses. | OEM Windows licenses preinstalled on PCs; OEM parts used by system integrators. |
PC | Personal Computer — general-purpose computer intended for individual use; commonly refers to IBM‑PC compatible systems running Windows/Linux. | Desktop/tower PC with x86‑64 CPU and discrete GPU. |
PCH | Platform Controller Hub — the modern Intel chipset, handling I/O functions for peripherals. | The Z690 PCH provides USB, SATA, and additional PCIe lanes. |
PSU | Power Supply Unit — converts AC mains to regulated DC rails to power computer components; rated by wattage and efficiency. | ATX PSUs providing +12V/+5V/+3.3V; 80 PLUS efficiency tiers; modular cabling. |
RTC | Real-Time Clock — hardware clock that keeps time across reboots/power cycles, often backed by a battery. | System reads RTC (CMOS/ACPI) at boot to set the OS clock. |
SBC | Single-Board Computer — complete computer on a single circuit board integrating CPU, memory, storage, and I/O. | Raspberry Pi, BeagleBone; runs Linux for embedded/edge. |
SIMT | Single Instruction, Multiple Threads — GPU execution model where groups of threads execute the same instruction on different data. | NVIDIA warp execution; branch divergence reduces efficiency. |
SMBIOS | System Management BIOS — firmware tables that describe hardware to the OS. | DMI/SMBIOS tables expose model, memory, and slots. |
SoC | System on Chip — integrated circuit that consolidates CPU cores, GPU, memory controllers, and I/O peripherals on a single die/package. | Smartphone/tablet SoCs (Apple M‑series, Qualcomm Snapdragon); embedded ARM SoCs. |
TPM | Trusted Platform Module — hardware-based security chip for keys and attestation. | TPM 2.0 used by Secure Boot and disk encryption. |
VHDL | VHSIC Hardware Description Language — a hardware description language used in electronic design automation to describe digital and mixed-signal systems. | Design FPGAs and ASICs with VHDL; entity , architecture , process . |
Historical | ||
PDA | Personal Digital Assistant — a handheld device that combined computing, telephone/fax, and networking features; a precursor to the smartphone. | Palm Pilot, Apple Newton, Windows CE devices. |
PIC | Programmable Interrupt Controller — legacy interrupt controller (e.g., Intel 8259A) that routes hardware IRQs to the CPU. | Classic x86 uses dual 8259 PICs remapped during OS init. |
PIT | Programmable Interval Timer — legacy timer chip (e.g., Intel 8253/8254) that divides a ~1.193182 MHz input clock to produce periodic interrupts for task scheduling and timekeeping. | Configure PIT channel 0 to generate IRQ0 for early OS scheduler ticks; retained as a fallback timer during boot. |
Firmware
Acronym | Meaning | Example |
---|---|---|
ACPI | Advanced Configuration and Power Interface — standard for power management and device configuration via tables provided by firmware. | ACPI tables (DSDT/SSDT) describe devices and power states to the OS. |
AML | ACPI Machine Language — pseudo-code bytecode interpreted by the OS to evaluate ACPI objects and methods from the DSDT/SSDTs. | AML interpreter in the kernel executes methods to handle power events. |
DSDT | Differentiated System Description Table — primary ACPI table from firmware containing the base definition of devices and power objects in AML. | The OS loads and interprets the DSDT at boot to enumerate devices. |
FADT | Fixed ACPI Description Table — ACPI table that provides pointers to other tables and defines fixed hardware register blocks. | Contains addresses for power management timers and SCI interrupt info. |
GRUB | GRand Unified Bootloader — a popular bootloader from the GNU project, used by most Linux distributions. | The GRUB menu for selecting an OS to boot; grub.cfg configuration. |
MADT | Multiple APIC Description Table — ACPI table that describes all the interrupt controllers (APICs, IOAPICs) in the system. | The OS uses the MADT to initialize CPUs and route interrupts in an SMP system. |
PnP | Plug and Play — automatic device detection, enumeration, and configuration by the OS/firmware, minimizing manual setup and IRQ/DMA conflicts. | ACPI/PCI PnP; USB devices enumerated and drivers auto‑loaded. |
PSCI | Power State Coordination Interface — ARM standard for power management, allowing an OS to request power state changes from system firmware. | OS uses PSCI calls for CPU hotplug, idle, and system shutdown. |
RSDP | Root System Description Pointer — firmware structure that locates the main ACPI tables (RSDT/XSDT) in memory for the OS. | The OS scans for the "RSD PTR " signature in low memory to find the RSDP. |
RSDT | Root System Description Table — 32-bit ACPI table that contains pointers to all other description tables. | Superseded by the 64-bit XSDT on modern systems. |
SBI | Supervisor Binary Interface — standard interface between a RISC‑V supervisor OS and machine‑mode firmware providing services (timers, IPIs, power, console) via SBI calls; commonly implemented by OpenSBI. | Boot flow: ROM/FSBL → OpenSBI (SBI firmware) → U‑Boot/Linux; OS issues ecall to SBI for privileged services. |
SCI | System Control Interrupt — a dedicated interrupt used by ACPI to signal power management and other system events to the OS. | ACPI SCI handler for lid open/close or power button events. |
SMI | System Management Interrupt — a high-priority interrupt that causes the CPU to enter System Management Mode (SMM). | Triggered by hardware or firmware to handle platform-specific events. |
SMM | System Management Mode — a special-purpose CPU mode in x86 for handling system-wide functions like power management and proprietary OEM code, transparent to the OS. | SMI handler for power button events; legacy USB keyboard emulation. |
SSDT | Secondary System Description Table — additional ACPI tables containing AML definitions that supplement or modify the DSDT. | Used for device-specific configuration or hot-plug support. |
UEFI | Unified Extensible Firmware Interface — modern firmware replacing legacy BIOS with a flexible boot and runtime services model. | UEFI boot managers, GPT disks, Secure Boot. |
XSDT | Extended System Description Table — 64-bit version of the RSDT that contains pointers to all other ACPI description tables. | Used by modern 64-bit operating systems to find ACPI tables. |
Legacy | ||
CSM | Compatibility Support Module — UEFI component that provides legacy BIOS services to boot non‑UEFI OSes and option ROMs; phased out on modern systems. | Enable CSM to boot legacy MBR media or old GPUs with legacy option ROMs. |
Historical | ||
APM | Advanced Power Management — legacy firmware interface for power management, superseded by ACPI. | APM BIOS calls for sleep/shutdown on pre-ACPI systems. |
BIOS | Basic Input/Output System — legacy PC firmware that initializes hardware and boots the OS. | PC firmware POST and boot sequence on legacy/CSM systems. |
POST | Power-On Self-Test — diagnostic sequence run by firmware (esp. legacy BIOS) at startup to check hardware integrity. | Beep codes on failure; memory/drive checks during boot. |
Culture & Misc
Acronym | Meaning | Example |
---|---|---|
AFAICT | As Far As I Can Tell — based on current understanding. | “AFAICT, the bug only affects Safari.” |
AFAIK | As Far As I Know — indicates incomplete knowledge. | “AFAIK, we don't support Windows 7 anymore.” |
AFK | Away From Keyboard — temporarily unavailable. | “AFK 10 mins, brb.” |
ASAP | As Soon As Possible — urgent request or prioritization; avoid ambiguity by specifying a concrete timeframe when possible. | “Please review ASAP” → “Please review by EOD.” |
ATM | At The Moment — current status may change. | “ATM we're blocked on upstream changes.” |
BDFL | Benevolent Dictator For Life — long-term project leader. | Python’s BDFL history. |
BOFH | Bastard Operator From Hell — cynical sysadmin trope. | Humor in ops culture. |
BRB | Be Right Back — brief step away. | “BRB, grabbing coffee.” |
BTW | By The Way — add side note/context. | “BTW, the API changed in v2.” |
DM | Direct Message — private one-to-one message in chat/social platforms. | “Send me a DM with the logs.” |
ELI5 | Explain Like I'm Five — request for simple explanation. | “ELI5 how RSA works.” |
EOD | End Of Day — end of a working day; common deadline shorthand. | “I'll have a draft ready by EOD.” |
EOW | End Of Week — end of the current work week; deadline shorthand. | “Targeting EOW for the feature toggle rollout.” |
EOY | End Of Year — end of the calendar or fiscal year; deadline shorthand. | “Let's target EOY for GA after extended beta.” |
ETA | Estimated Time of Arrival — expected completion/arrival time. | “ETA for fix is 3pm.” |
FFS | For F***'s Sake — expression of frustration or exasperation; avoid in formal communication. | “FFS, the build broke again.” |
FOMO | Fear Of Missing Out — anxiety about missing experiences or opportunities others are having. | “Skip the release party? FOMO is real.” |
FTW | For The Win — enthusiastic endorsement or celebration of something that worked well. | “Feature flags FTW — painless rollback.” |
FUD | Fear, Uncertainty, Doubt — disinformation tactic. | Competitor FUD. |
FWIW | For What It's Worth — modest preface to share input without asserting authority. | “FWIW, retry with exponential backoff.” |
FYI | For Your Information — share info without requiring action. | “FYI: maintenance window Sunday 2am.” |
GTK | Good To Know — acknowledges helpful info. | “Rate limit resets hourly — GTK.” |
HN | Hacker News — tech news and discussion site run by Y Combinator. | Post a launch on news.ycombinator.com; join the discussion. |
HTH | Hope This Helps — friendly sign‑off when providing assistance or an answer. | “HTH! Ping me if you need more details.” |
ICYMI | In Case You Missed It — pointer to noteworthy info shared earlier. | “ICYMI, the outage postmortem is posted.” |
IDK | I Don't Know — lack of information. | “IDK the root cause yet; investigating.” |
IIRC | If I Recall Correctly — hedged memory. | “IIRC, that was fixed in 1.2.” |
IIUC | If I Understand Correctly — confirm interpretation. | “IIUC, only a config change is needed.” |
IMHO | In My Humble Opinion — opinion preface. | “IMHO, we should simplify.” |
IMO | In My Opinion — opinion preface; a slightly less self-deprecating variant of IMHO. | “IMO, we should ship feature‑flagged.” |
IRL | In Real Life — referring to the physical/offline world as opposed to online/virtual contexts. | “Let's meet IRL next week.” |
LGTM | Looks Good To Me — code review approval. | “LGTM, ship it.” |
LMGTFY | Let Me Google That For You — snarky suggestion to search the web first; use sparingly as it can come across as dismissive. | “LMGTFY: how to clear npm cache.” |
LMK | Let Me Know — request a follow-up. | “LMK if the deploy finishes.” |
MAME | Multiple Arcade Machine Emulator — a free and open-source emulator designed to recreate the hardware of arcade game systems in software. | Preserve gaming history by playing classic arcade games with MAME. |
MOTD | Message Of The Day — login banner/notice. | /etc/motd on login. |
NBD | No Big Deal — indicates something is minor or not worth worrying about. | “Missed the standup — NBD.” |
NIH | Not Invented Here — bias to build your own instead of using existing solutions. | Replacing a mature library with custom code. |
NP | No Problem — acknowledgment that a request is fine or a task is acceptable. | “NP, I can take this.” |
NSFW | Not Safe For Work — content that may be inappropriate for professional settings. | “NSFW: explicit language/images; open privately.” |
OOO | Out Of Office — unavailable for work/response. | “OOO until Monday.” |
OP | Original Poster — thread/issue creator. | “Per OP’s repro steps …” |
OT | Off Topic — content not related to the main subject/thread. | “OT: anyone tried the new keyboard switches?” |
OTOH | On The Other Hand — introduces a contrasting point or alternative perspective. | “We can optimize now; OTOH, premature optimization adds risk.” |
PEBKAC | Problem Exists Between Keyboard And Chair — user error. | Misconfigured client settings. |
PITA | Pain In The Ass — something annoying or cumbersome; avoid in formal communication. | “That migration was a PITA.” |
PTO | Paid Time Off — time away from work. | “On PTO next week.” |
Quick Question — brief, low‑effort question or nudge for a short answer. | “QQ: is staging using the new DB URL?” | |
RIP | Rest In Peace — tongue-in-cheek epitaph for a feature, service, or idea that just failed or was deprecated. | “RIP staging cluster after that migration.” |
RPG | Role-Playing Game — a game in which players assume the roles of characters in a fictional setting. | Tabletop RPGs like D&D; computer RPGs like Final Fantasy. |
RTFM | Read The F***ing Manual — read docs first. | git rebase --help . |
SME | Subject-Matter Expert — domain expert. | Security SME review. |
SMH | Shaking My Head — expresses disappointment or disbelief. | “Prod creds in a script? SMH.” |
SO | Stack Overflow — popular Q&A site for programming and software development. | Link to an accepted SO answer for a solution/workaround. |
TANSTAAFL | There Ain't No Such Thing As A Free Lunch — highlights that every choice has trade‑offs or hidden costs; nothing is truly free. | “TANSTAAFL: caching speeds reads but adds complexity/invalidation.” |
TBA | To Be Announced — details later. | Rollout date TBA. |
TBD | To Be Determined — not finalized. | Owner TBD after planning. |
TBH | To Be Honest — candid preface. | “TBH, refactor first.” |
TFA | The F***ing Article — read the article. | TFA explains REST vs RPC. |
TIA | Thanks In Advance — polite sign‑off indicating appreciation for help to come; consider whether it pressures recipients. | “TIA for reviewing the PR.” |
TIL | Today I Learned — sharing a new fact or insight just learned. | “TIL git worktree simplifies multi-branch checkouts.” |
TL;DR | Too Long; Didn't Read — summary. | TL;DR: Use approach B. |
TLA | Three-Letter Acronym — meta-acronym. | “Another TLA.” |
TTYL | Talk To You Later — casual sign-off indicating you’ll continue the conversation later. | “Gotta run — TTYL.” |
WCGW | What Could Go Wrong — tongue-in-cheek before risk. | “Deploy Friday, WCGW?” |
WFH | Work From Home — remote from home. | “WFH today.” |
WTF | What The F*** — expression of surprise, confusion, or frustration; avoid in formal communication. | “WTF happened to the build pipeline?” |
YMMV | Your Mileage May Vary — results differ. | Different env outcomes. |
YOLO | You Only Live Once — humorously justifies taking a risk; use with care. | "YOLO deploy" on Friday — probably don't. |
Legacy | ||
MUD | Multi-User Dungeon — a text-based, online multiplayer role-playing game; a precursor to MMORPGs. | Connect via Telnet; DikuMUD, LPMud, MUSH/MUCK/MOO variants. |
Organizations
Acronym | Meaning | Example |
---|---|---|
ACM | Association for Computing Machinery — international learned society for computing, publishing journals, conferences, curricula, and best practices. | ACM SIGs (SIGGRAPH, SIGPLAN), ACM Digital Library, Turing Award. |
ANSI | American National Standards Institute — U.S. standards organization that oversees and coordinates standards development and accredits standards bodies. | ANSI C (C89/C90) standardization; coordinates U.S. positions in ISO/IEC JTC 1. |
ASF | Apache Software Foundation — non‑profit that supports Apache open source projects and communities. | Apache HTTP Server, Hadoop, Kafka, Spark under the ASF. |
CNCF | Cloud Native Computing Foundation — part of the Linux Foundation hosting cloud‑native projects and standards. | Kubernetes, Prometheus, Envoy; CNCF landscape and graduation levels. |
ECMA | Ecma International — industry association for information and communication systems standards. | ECMAScript (JavaScript), C# (ECMA-334), CLI (ECMA-335). |
EFF | Electronic Frontier Foundation — a non-profit organization defending civil liberties in the digital world. | Advocates for privacy, free speech, and innovation online. |
FSF | Free Software Foundation — GNU/GPL steward. | Publishes GPL family. |
GNU | GNU’s Not Unix — FSF project and philosophy. | GNU toolchain/userland. |
IANA | Internet Assigned Numbers Authority — coordinates global IP addressing, DNS root zone management (with ICANN), and protocol parameter registries (ports, DHCP options, etc.). | Port numbers and protocol parameters registries; root zone management with ICANN. |
ICANN | Internet Corporation for Assigned Names and Numbers — oversees the global DNS root, IP address allocation policy coordination, and domain name registries/registrars. | gTLD/ccTLD policies; WHOIS/RDAP; root zone stewardship. |
IEEE | Institute of Electrical and Electronics Engineers — professional association and standards body producing technical standards. | IEEE 802 (Ethernet/Wi‑Fi), IEEE 754 floating‑point. |
IETF | Internet Engineering Task Force — open standards body that develops and publishes internet standards as RFCs. | HTTP/1.1 (RFC 723x), TLS (RFC 8446), QUIC (RFC 9000); working groups and I-Ds. |
ISO | International Organization for Standardization — independent, non‑governmental international standards body. | ISO 8601 dates/times; ISO/IEC 9899 (C), ISO/IEC 14882 (C++). |
ITU‑T | International Telecommunication Union — Telecommunication Standardization Sector; develops telecom standards (Recommendations) for networks, media, and services. | ITU‑T H.264/H.265 (with ISO/IEC), G.711/G.722 codecs; numbering, signaling, and transport Recs. |
NIST | National Institute of Standards and Technology — U.S. federal agency that develops standards, guidelines, and measurements to improve technology, cybersecurity, and commerce. | NIST SP 800‑53/63/171 security guidelines; NIST hash/SHA competition; time services. |
OASIS | OASIS Open — consortium that develops open standards for security, identity, content, and more. | SAML, STIX/TAXII, KMIP; technical committees and OASIS specifications. |
OMG | Object Management Group — consortium that develops technology standards, notably modeling/specification standards. | UML, CORBA, BPMN standards; working groups and specifications. |
OSI | Open Source Initiative — OSI-approved licenses. | Open Source Definition stewardship. |
OWASP | Open Web Application Security Project — a non-profit foundation focused on improving software security. | The OWASP Top 10 list of critical web application security risks; OWASP ZAP scanner. |
PCI-SIG | Peripheral Component Interconnect Special Interest Group — consortium that develops and maintains PCI and PCI Express specifications and compliance programs. | PCIe 5.0/6.0 specs, CEM/ECNs; compliance workshops and device interoperability testing. |
SPEC | Standard Performance Evaluation Corporation — develops industry‑standard benchmarks for computing performance and energy. | SPEC CPU, SPECjbb, SPECpower; widely cited performance metrics. |
TPC | Transaction Processing Performance Council — benchmarks for database and transaction processing systems. | TPC‑C (OLTP), TPC‑H/TPC‑DS (analytics), audited results and full disclosure reports. |
W3C | World Wide Web Consortium — standards body that develops web specifications and recommendations. | HTML/CSS/DOM specs; Working Groups and drafts at w3.org. |
WHATWG | Web Hypertext Application Technology Working Group — community maintaining living standards for HTML, DOM, and related web platform technologies. | HTML Living Standard; DOM and URL standards co‑developed with browsers. |
Licensing & Open Source
Acronym | Meaning | Example |
---|---|---|
AGPL | GNU Affero GPL — copyleft with network-use clause. | SaaS must release source of modifications. |
BSD | Berkeley Software Distribution — permissive license family. | BSD-2, BSD-3 clause variants. |
EULA | End-User License Agreement — contract between software provider and end user defining usage rights/restrictions; common for proprietary software. | Accept EULA during installation; governs redistribution and usage. |
FLOSS | Free/Libre and Open Source Software — umbrella term. | General discussions of FLOSS. |
FOSS | Free and Open Source Software — umbrella term. | FOSS projects and communities. |
GPL | GNU General Public License — strong copyleft. | Derivatives must remain open. |
LGPL | GNU Lesser GPL — weak copyleft for linking. | Use in libraries linkable from proprietary apps. |
MIT | MIT License — simple permissive license. | Many JS libs under MIT. |
OSS | Open Source Software — software under OSI licenses. | OSS adoption. |