Technology

Space Station Processing Facility NASA's Space Station Processing Facility at Kennedy Space Center: a large integration and testing center for International Space Station hardware, future station elements and resup…

Space–time tradeoff in computing: principles, patterns, and examples Space-time tradeoff Explanation of the space–time (time–memory) tradeoff in computing: what it means, common techniques, historical notes, practical examples (compression, caching, cryptography) and d…

Spade — design, uses, history and differences from a shovel Spade A spade is a hand tool for digging and cutting soil, distinct from a shovel; also a playing-card suit. Overview, types, history, uses, care and notable facts.

Spectrograph: instrument for separating and recording a wave spectrum Spectrograph An overview of spectrographs: how they separate waves into spectra, main components, historical development, common types and applications in astronomy, chemistry, acoustics and re…

Speech recognition: principles, history, applications and challenges Speech recognition Overview of speech recognition: how spoken language is converted to text, main components and models, history, common uses, limitations, privacy concerns and future directions.

Spencer repeating rifle A mid‑19th century lever‑action, seven‑shot rimfire repeating rifle invented by Christopher M. Spencer (patented 1860), noted for its tubular buttstock magazine and service in the…

Spinning Jenny: Invention, Design, and Impact on Textile Production Spinning jenny The spinning jenny, invented c.1764 by James Hargreaves in Lancashire, multiplied yarn output by using multiple spindles. This article covers its design, history, economic effects…

Spintronics: electronics based on electron spin Spintronics Spintronics studies and uses the electron spin and its magnetic moment in solids to store, sense and manipulate information, enabling non‑volatile memories, sensitive sensors and l…

Sponge (cleaning tool): materials, structure, history and uses Sponge (tool) A sponge is a porous cleaning implement—natural or synthetic—used for washing, wiping and absorbing. Covers structure, common materials, history, care, uses and environmental consi…

Spreadsheet (computer application) Spreadsheet An overview of spreadsheets: what they are, key parts and features, a brief history, common uses, and important limitations and distinctions.

Spring (device): types, materials, uses, and behavior Spring (device) A spring is an elastic mechanical component that stores and releases energy. Article covers common types, materials, history, manufacturing, applications, and important safety and…

Sputnik programme: Soviet satellite initiative and its global impact Sputnik programme The Sputnik programme was the Soviet Union's early satellite initiative. Beginning with Sputnik 1 in 1957, it demonstrated orbital flight, catalyzed the Space Race, and reshaped sc…

Spyware: definition, types, risks, and prevention Spyware Spyware is software that covertly gathers information from devices. This article describes types, how it spreads, typical uses, harms, detection and practical steps to reduce risk.

Spyware removal software: tools, methods, and best practices Spyware removal software Comprehensive guide to spyware removal software: how it works, common removal techniques, prevention strategies, and when a full OS reinstall may be necessary.

SQR codes (Secure Quick Response codes) SQR codes Encrypted two-dimensional QR-style barcodes that encode protected data for authentication, payments, ticketing and one-time transfers; readable by cameras but requiring keys or app…

Stack (data structure) An abstract data type that stores elements in last-in, first-out order. Explains operations, implementations, history, use cases, and common variants with practical examples.

Stack machine (computational model) Stack machine A stack machine is a computation model that uses one or more stacks to hold operands and intermediate results. It underlies many virtual machines, interpreters and expression evalu…

Standard ML (SML): a statically typed functional programming language Standard ML Standard ML (SML) is a statically typed, functional language in the ML family, known for type inference, pattern matching, a modular system, and use in compilers, research and theo…

Stapler: function, types, parts and practical use Stapler A stapler is a common fastening device that binds thin materials such as paper with metal staples. This article explains how staplers work, their main parts, types, history, uses a…

Star network topology Star network A star network connects every node to a central device (hub, switch or access point). It is widely used in LANs for its simplicity, ease of troubleshooting and clear physical layou…

Start menu Central interface element used to find and launch applications, access files and settings, and manage power and account options across desktop operating systems.

Static random-access memory (SRAM) Static random-access memory SRAM is a fast, volatile semiconductor memory that stores each bit in bistable circuits. It trades density and cost for speed and simplicity and is widely used for processor caches…

Station-to-Station (STS) protocol Station-to-Station protocol A cryptographic authenticated key-agreement protocol based on Diffie–Hellman that adds mutual authentication, explicit key confirmation, and perfect forward secrecy, developed in t…

Stealth (concealment and stealth technology) Stealth Stealth is the practice and technology of reducing detection by observers or sensors, applied in military platforms, personal concealment, and electronic systems to lower visibilit…

Stealth technology (low observability): principles, methods and applications Stealth technology Stealth technology, or low observable (LO) techniques, reduces detectability of vehicles and weapons across radar, infrared, acoustic and visual spectra using shaping, materials an…

Stepper motor: operation, types, control methods and applications Stepper motor A stepper motor is an electric motor that moves in discrete steps. This article explains its construction, common types, driving methods (full/half/microstepping), applications, ad…

Stereophonic sound (stereo) Stereo Stereophonic sound reproduces audio using two or more spatially separated channels and speakers to create directional cues and a sense of space; common in music, film, broadcasting…

Sticky note (Post-it): history, design, and common uses Sticky note Small, repositionable paper notes with a low-tack adhesive strip used for reminders, organization, and brainstorming; developed at 3M and popularized as Post-it notes.

Stock-Keeping Unit (SKU) Stock-Keeping Unit A stock-keeping unit (SKU) is a unique code used by a retailer to identify a specific product variant for inventory, pricing, and sales tracking; it differs from universal barcodes…

Stop error screen (Blue Screen of Death and equivalents) Stop error screen A stop error screen is an operating-system or firmware message shown when a device encounters a fatal error it cannot recover from; it displays diagnostic details and often forces…

Stopwatch — handheld device for measuring elapsed time Stopwatch A stopwatch records elapsed time for short intervals. Articles cover types, operation, history, common uses (sports, labs, industry), and differences between mechanical and digital…

Storage Storage: practices and places for preserving physical goods and digital information, covering types, design concerns, historical development, common uses, and key distinctions.

Storage area network (SAN) Storage area network Centralized block-level storage network that presents remote disks to hosts as local devices; used for high-performance enterprise storage, virtualization, databases, and backup.

Strasskirchen Solar Park (Straßkirchen, Germany) Strasskirchen Solar Park Large photovoltaic power station near Straßkirchen, Germany, with an installed capacity of about 54 MW; notable early example of utility-scale solar in Germany.

Structured program theorem The structured program theorem states that any computable program can be composed from three control constructs—sequence, selection, and repetition—underpinning the structured prog…

Stuxnet: the industrial cyber weapon that targeted Iran's centrifuges Stuxnet Stuxnet is a sophisticated computer worm discovered in 2010 that targeted industrial control systems—notably Iranian nuclear centrifuges—using multiple zero-days, stolen certificat…

Subaru Impreza: compact car with rally heritage Subaru Impreza The Subaru Impreza is a compact car produced by Subaru since 1992. Known for its boxer engine and symmetrical all-wheel drive, it spawned performance WRX/STI variants and has had s…

Subroutine (procedure, function): definition, structure, and uses Subroutine A subroutine is a named, reusable block of program code invoked from other code. This article explains its structure, history, common uses, and how it differs from functions, metho…

Subscripts and Superscripts: Typographic conventions, uses, and technical considerations Subscript and superscript Guide to subscripts and superscripts: typographic conventions, uses in chemistry, mathematics and editing, plus practical technical methods and accessibility considerations for web…

Subsonic (speeds below the speed of sound) Subsonic Motion at speeds below the local speed of sound. Applies to aeronautics, acoustics, ballistics and a namesake media-server application; contrasts with transonic, supersonic and hyp…

Subwoofer A loudspeaker specialized for low-frequency sound reproduction (bass and sub-bass). Used in home audio, cinemas, cars and live sound to extend and reinforce audio below the range o…

Sundial (solar time instrument) Sundial A sundial indicates local solar time by the shadow of a fixed object. This article explains its parts, how it works, major types, historical development, uses and limitations.

Super Game Boy A Nintendo cartridge adapter for the Super NES that plays Game Boy games on a TV with added color, borders and enhanced features; later updated as the Japan-only Super Game Boy 2.

Super Nintendo Entertainment System (SNES) Super Nintendo Entertainment System The Super Nintendo Entertainment System (SNES) is Nintendo’s 16-bit home console from the early 1990s, known for advanced 2D graphics, cartridge expansion chips, a rich game librar…

Super OS — an Ubuntu‑based 'out of the box' Linux distribution Super OS Super OS (formerly Super Ubuntu) is an Ubuntu-based distribution that aimed to provide a ready-to-use desktop with extra codecs, drivers and applications while retaining compatibil…

Super Scope — Super NES light gun peripheral Super Scope The Super Scope is Nintendo's bazooka-shaped light gun for the Super Nintendo Entertainment System, a wireless, battery-powered successor to the NES Zapper used for a small library…

Supercapacitor (Ultracapacitor): high‑power electrochemical capacitor Supercapacitor A supercapacitor is an electrochemical capacitor that stores more charge than conventional capacitors, offering very high power delivery, long cycle life, and rapid charge/discharg…

Supercharger — engine forced-induction device Supercharger A supercharger is a mechanically driven compressor that raises intake air pressure and density to increase internal-combustion engine power. Used in aviation, automotive, marine an…