SA (Software Assurance)
A software license maintenance offering from Microsoft.

SAA (Systems Application Architecture)
IBM's name for the architecture once intended to unify its disparate computer architectures.

SAIC (Science Applications International Corp.)
An IT and systems integration company, founded in 1969 and headquartered in San Diego.

SAM (software asset management)
A process for making software acquisition and disposal decisions. It includes strategies that identify and eliminate unused or infrequently used software, consolidating software licenses or moving toward new licensing models. See asset management.

SAML (Security Assertion Markup Language)
An Extensible Markup Language (XML)-based mechanism that enables disparate entities to exchange identity-related security information. This information is presented as assertions about authentication, authorization or various attributes of the identity in question. See XML.

SAN (storage area network)
A storage network that consists of two tiers: The first tier — the storage plumbing tier — provides connectivity between nodes in a network and transports device-oriented commands and status. At least one storage node must be connected to this network. The second tier — the software tier — uses software to provide value-added services that operate over the first tier.

SANS Institute
A research and education organization based in Bethesda, Maryland, that provides information security training and certification. The acronym stands for "sysadmin, audit, network, security."

SAP
An enterprise resource planning (ERP) vendor based in Walldorf, Germany. The letters "SAP" stand for "Systeme, Anwendungen, Produkte in der Datenverarbveitung," German for "Systems, Applications and Products in Data Processing." See ERP.

SAPI (Speech Application Programming Interface)
A Microsoft programming standard designed to help developers to incorporate speech recognition and text-to-speech functions into applications.

SAS Institute
A business intelligence software vendor, founded in 1976 and headquartered in Cary, North Carolina.

satellite communications
The use of geostationary orbiting satellites to relay transmissions from one earth station to another or to multiple earth stations.

SATS (semiconductor assembly and test services)
Services wherein which a supplier performs some or all of the operations associated with semiconductor packaging, assembly and testing under contract to a customer.

SAX (Simple API for XML)
A public-domain alternative to Document Object Model (DOM) for enabling programming languages to work with XML documents. SAX is application programming interface (API) that uses "start events" and "stop events" to parse an XML document so that an application can interact with it. In essence, it provides the application with a "keyhole view" of the document without describing its overall structure. See API, XML and DOM.

SCADA (supervisory control and data acquisition)
A system used in manufacturing for acquiring measurements of process variables and machine states, and for performing regulatory or machine control across a process area or work cell.

scalability
The measure of a system's ability to increase or decrease in performance and cost in response to changes in application and system-processing demands. Examples would include how well a hardware system performs when the number of users is increased, how well a database withstands growing numbers of queries, or how well an operating system performs on different classes of hardware. Enterprises that are growing rapidly should pay special attention to scalability when evaluating hardware and software.

scanner
A device that renders a printed image (such as a photograph or business document) as a stream of bits for electronic image capture or transmission purposes.

scattering
A cause of signal loss in fiber-optic transmission. Scattering is the diffusion of a light beam caused by microscopic variations in the material density of the transmission medium.

SCE (supply chain execution)
A subset of supply chain management (SCM). SCE is a framework of execution-oriented applications that enable the efficient procurement and supply of goods, services and information across enterprise boundaries to meet customer-specific demand. In its broadest sense, SCE includes manufacturing execution systems, warehouse management systems and other execution systems within the enterprise, as well as throughout the supply chain. The logistics-oriented elements of SCE include transportation management, warehouse management and supply chain inventory visibility systems. See SCM.

schematic
A diagram that details the electrical elements of a circuit or system.

SCIV (supply chain inventory visibility)
A category of applications that allow enterprises to monitor and manage events across the supply chain to plan their activities more effectively and pre-empt problems. SCIV systems enable enterprises not only to track and trace inventory globally on a line item level, but also submit plans and receive alerts when events deviate from expectations. This visibility into orders and shipments on a real-time basis gives enterprises reliable advance knowledge of when goods will arrive.

SCM (semiconductor contract manufacturing)
A service in which a supplier performs some or all semiconductor manufacturing operations under contract to a customer. In its broadest sense, SCM can encompass wafer fabrication, packaging, assembly and testing of semiconductor products.

SCM (software configuration management)
Also known as "software change management," SCM is a methodology for software change request initiation and tracking, change impact analysis, distribution, version control, security administration, and quality reviews.

SCM (supply chain management)
The process of optimizing the delivery of goods, services and information from supplier to customer. SCM is a set of business processes that engages a trading-partner community in the common goal of satisfying the end customer. Functionally, SCM encompasses both supply chain planning (SCP) and supply chain execution (SCE) processes. See SCP and SCE.

SCO (Santa Cruz Operation)
A company founded in 1979 and best known in the 1990s for its Unix-based operating-system products. In 2001, SCO sold off its Unix business to Caldera and changed its name to Tarantella (after the thin-client product it launched in 1997 and retained after the Caldera deal). Caldera, in turn, changed its own name to SCO Group to capitalize on the recognized SCO brand name.

SCOR (Supply Chain Operations Reference)
A supply chain management (SCM) reference model from the Supply-Chain Council. It includes a common supply chain framework, terminology, common metrics and benchmarks, and best practices. SCOR can be used as a model for evaluating, positioning and implementing SCM software.

SCORM (Shareable Content Object Reference Model)
A reference model containing specifications for e-learning capabilities supporting interoperability and accessibility, created in 1999 in an initiative led by the U.S. Department of Defense working with other government agencies and the private sector. SCORM was developed in support of the Defense Department's Advanced Distributed Learning Initiative as a means integrating and the work of these organizations into a common reference model. The model contains:

SCP (service control point)
The database at the apex of a Signaling System 7 (SS7) network, containing information on how to process, route and bill calls. See SS7.

SCP (Supply Chain Planner)
A supply-chain-planning tool from i2 Technologies (Irving, Texas).

SCP (supply chain planning)
A subset of supply chain management (SCM), SCP is the process of coordinating assets to optimize the delivery of goods, services and information from supplier to customer, balancing supply and demand. An SCP suite sits on top of a transactional system to provide planning, what-if scenario analysis capabilities and real-time demand commitments. Typical modules include network planning, capacity planning, demand planning, manufacturing planning and scheduling, distribution and deployment planning, and transportation planning and scheduling.

SCPC (single channel per carrier)
A transmission system in which a physical channel is allocated solely to one carrier for the duration of the transmission.

SCR (sustainable cell rate)
In asynchronous transfer mode (ATM), the average cell rate a source is allowed to maintain. See ATM.

screen pop
A call center system function that populates an agent's screen with just-in-time customer information.

screen sharing
A feature of data-conferencing and other real-time collaboration technologies that enables multiple users to view the same document or computer screen simultaneously. Unlike application sharing, screen sharing allows only one user, rather than multiple users, to control the screen or document. See application sharing.

SCS (sales configuration system)
A system used to automate the configuration of ship-to-order, assemble-to-order or engineer-to-order products, and to configure product-related information, such as pricing, discounts and customized financing plans. SCSs (also known as "sales configurators") are designed to reduce complexity and improve productivity for salespeople by helping them match customer needs to unique products and service offerings.

SCSA (Signal Computing System Architecture)
A layered hardware/software architecture for building multivendor computer-telephony integration (CTI) systems. Originally defined by Dialogic, SCSA was later handed off to the Enterprise Computer Telephony Forum (ECTF). See CTI and ECTF.

SCSI (Small Computer System Interface)
A peripheral interface for up to seven devices. SCSI provides a high-speed, parallel data transfer of up to 40 megabits per second (Mbps) and has the advantage of connecting multiple peripherals while taking up only one slot in the computer.

SCSL (Sun Community Source Licensing)
The Sun Microsystems license model for Java. The agreement leverages a community-based development model similar to "open-source software" initiatives that have existed over the years.

SDH (Synchronous Digital Hierarchy)
A standard for digital transmission over optical networks in Europe. SDH is the European equivalent of the Synchronous Optical Network (SONET), with transmission speeds and network management suited to the European market. See SONET.

SDK (software development kit)
A set of development utilities for writing software applications, usually associated with specific software environments (for example, the Java Development Kit).

SDLC (Synchronous Data Link Control)
An IBM-defined protocol used for serial (by bit) information transfer over a data communications channel. Concerned with the lower two layers of the Open Systems Interconnection (OSI) model (the physical and data link layers), SDLC was part of IBM's Systems Network Architecture (SNA) attack on the diverse link controls, access methods and terminal types that existed in the pre-SNA era. See SNA and OSI.

SDLT (Super Digital Linear Tape)
A Quantum storage product architecture that extends the capacity and transfer rate of digital linear tape (DLT) drives. See DLT.

SDRAM (synchronous dynamic random-access memory)
A category of dynamic random-access memory (DRAM) in which memory access is synchronized with the system bus data transfer rate The introduction of SDRAM in the late 1990s enabled a major improvement in system performance over traditional, asynchronous varieties of DRAM technology. See DRAM.

SDSL (symmetric digital subscriber line)
A digital subscriber line (DSL) technology that operates over voice-grade lines at 1.5 megabits per second one way, or 768 kilobits per second both ways, over an 8,000-foot distance. See DSL.

SEA-ME-WE (Southeast Asia-Middle East-Western Europe 2)
A submarine cable network that went into operation in 1994, linking over one dozen countries from France to Singapore.

SEA-ME-WE 3 (Southeast Asia-Middle East-Western Europe 3)
A fiber-optic submarine cable network that went into service in 1999, linking over 30 countries between Western Europe and Southeast Asia.

search engine
A tool that enables Web pages to be found and retrieved based on the words they contain. Search engines use a searchable index of Web pages that is automatically updated by spiders or Web crawlers and housed on a central server connected to the Internet. Examples include Google, Yahoo and AltaVista.

search index
A machine-searchable matrix of documents used by a search engine.

SECAM (Sequential Couleur a Memoire)
A color television broadcasting system using 625 picture lines and a 50-hertz field frequency, in which the two color-difference signals are transmitted sequentially instead of simultaneously. It was developed in France and is also used in the former Soviet Union. See NTSC and PAL.

second-generation office systems
The class of multiuser, time-sharing, integrated office systems introduced around 1983, including Digital Equipment's ALL-IN-1 and IBM's PROFS. These products were largely superseded by client/server third-generation products of the 1990s.

secret key
The symmetric key used in secret-key cryptography. It is a secret shared between communicating parties, but is not truly private. See secret-key cryptography, private key and public-key cryptography.

secret-key cryptography
In this cryptography method (also known as symmetric-key cryptography), the single key needed to encrypt and decrypt messages is a shared secret between the communicating parties. The biggest problem with this method is that the secret key must be communicated through an external mechanism separate from the communication channel over which the encrypted text flows. In addition, secret-key systems do not support digital signatures. These limitations are addressed in public-key cryptography (see separate entry).

SEI (Software Engineering Institute)
A recognized source of research, process models and appropriate practices for application development. Based at Carnegie Mellon University, the SEI uses its Capability Maturity Model (CMM) as a framework for examining the adequacy of an enterprise's processes and improving those processes. It also provides hands-on experience to practitioners through groups such as software process improvement networks. See CMM.

self-describing
A term denoting messages that contain not only data, but also metadata that describes the format and the meaning (that is, the syntax and the semantics) of that data. For example, Extensible Markup Language (XML) is a self-describing message format that consists of tag/value pairs. See XML.

self-test
A feature in which a system tests itself — typically at predetermined times, such as during system startup or shutdown routines — and issues an alert if any faults are found. This feature often expedites service by pinpointing faulty equipment, saving diagnostic time.

sell side
A general term encompassing services or processes associated with the vendor (as opposed to buyer) side of business-to-business transactions, such as supply chain management methods and tools.

SEM (Strategic Enterprise Management)
A suite of SAP analytical applications that support integrated planning, decision making and performance monitoring. SEM uses multidimensional online analytical processing (OLAP) functionality to process data held in SAP's Business Information Warehouse. See OLAP.

semantics
The basic meaning of data items and the relationships among them. Semantic data descriptions make it easier to develop application programs and to maintain the consistency of data when it is updated.

semantic net
A type of knowledge representation used in some text mining or search tools. Semantic nets are graphs in which nodes represent key phrases, and the thicknesses of the links represent the frequency of their co-occurrence nearby in the same document.

serial
A term describing a sequential flow of bits over a single pathway. See serial interface and serial transmission.

serial interface
An interconnection that transmits information bit by bit rather than a whole character at a time. It is much slower and cheaper than a parallel interface.

serial transmission
A method whereby the bits of a character are sent sequentially on a single transmission channel. See parallel transmission.

server
A system or a program that receives requests from one or more client systems or programs to perform activities that allow the client to accomplish certain tasks. The term usually denotes computers that provide specific services to other computers on a network. Routing servers connect subnetworks of like architecture; gateway servers connect networks of different architectures by performing protocol conversions; and terminal, print and file servers provide interfaces between peripheral devices and systems on the network.

server appliance
A type of computing appliance that creates, manipulates or provides information to other network-connected computing devices. Unlike storage appliances, server appliances use an application context for the creation, manipulation or provision of information. Examples include Sun Microsystems' Cobalt Qube, Oracle's 8i Appliance and Dell Computer's PowerApp.web. Potential server appliance functions include database, e-mail, file storage and directory services. See computing appliance and storage appliance.

server virtualization
The pooling of server resources in a way that masks the physical nature and boundaries of those resources from users or administrators.

service bureau
A company that processes various types of data for a client for a fee. For example, a telephone service bureau typically provides call detail reporting (CDR) and call-costing reports. See CDR.

service desk
A help desk that is equipped with the resources for resolving service requests and problem calls. A service desk gives the customer service representative the ability to efficiently diagnose, troubleshoot and correct technical-support problems (rather than merely relaying a message or handing off the call to another party).

service pack
A minor software product revision that contains feature updates or bug fixes, but not enough new code to warrant a new version number.

servlet
A server-side Java process that operates in conjunction with a Web server and offers an alternative to using Common Gateway Interface (CGI) and server application programming interfaces to communicate with Web server processes. Servlets are independent of a given type of Web server, as the most prominent Web servers support servlets. See Java.

session layer
Layer 5 of the Open Systems Interconnection (OSI) reference model for network architectures. See OSI.

SET (Secure Electronic Transaction)
A standard in conceived 1995 by Visa and MasterCard to ensure that all Internet-based payment transaction details are encrypted, the parties authenticated, acknowledgments fully recorded and the customer payment details made available only to the bank. Due to its complexity and security flaws, SET failed to gain widespread acceptance. Meanwhile, Visa and MasterCard have pushed ahead with their own, separate standards: Verified by Visa and MasterCard Secure Payment Application.

SFA (sales force automation)
The use of technology to automate the sales process. Technologies used in SFA include laptop computers, personal digital assistants, contact databases and interactive selling systems.

SFC (shop floor control)
A system of computers and controllers used to schedule, dispatch and track the progress of work orders through manufacturing based on defined routings.

SG&A (selling, general and administrative)
A category of expenses reported in corporate financial statements.

SGML (Standard Generalized Markup Language)
An International Organization for Standardization (ISO) standard adopted in 1986 for the markup of electronic documents, identifying the basic structural elements of a text document. SGML addresses the structure of a document, not its format or presentation. See ISO.

SHA (Secure Hash Algorithm)
An authentication algorithm developed by the U.S. National Institute of Standards and Technology and National Security Agency, designed for use with digital signatures.

shared services
The centralization and consolidation of multiple service departments or functions into a single organization — often called a shared service center (SSC). Shared services reduce personnel costs and build expertise. Consolidating to one central location or process lowers cost and increases efficiency. See SSC.

shell
A user interface environment that is usually character-based (as opposed to a graphical user interface), and is provided as a feature of some operating systems (for example, Linux).

shim
A software modification inserted into an operating system or application, to intercept the normal data flow and provide additional functionality. Often used by third party vendors to provide enhanced networking features or intrusion detection functions.

S-HTTP (Secure Hypertext Transport Protocol)
Also known as HTTPS, this is an extension of Hypertext Transport Protocol (HTTP) that provides security services for transaction confidentiality, authenticity and integrity between HTTP servers and clients. For the purposes of Internet browsers, S-HTTP is a competitive alternative to the more widely used Secure Sockets Layer (SSL) standard. Developed by Enterprise Integration Technologies (which was acquired by Verifone in 1995), S-HTTP was designed for use in browser applications, so it cannot be used to secure non-browser-based Internet applications.

SIC (Standard Industrial Classification)
A system of numeric codes defined by the U.S. government for the purposes of identifying numerous business categories in a range of industry sectors, such as agriculture, mining, manufacturing, wholesale and retail trade, and business services.

sideband
A frequency band on either the upper or lower side of the carrier frequency within which fall the frequencies produced by the process of modulation.

SIDM (serial impact dot matrix)
A type of printer, suitable for making carbon copies, but now largely obsolete.

signal
A physical, time-dependent energy value used for the purpose of conveying information through a transmission medium, such as copper, fiber or air.

signaling
The process by which a caller or equipment on the transmitting end of a communication channel informs a particular party or equipment at the receiving end that a message is to be communicated.

signature verification
A biometric technique that uses characteristics of a person's signature (including pressure, pen lifts, and speed and direction of pen strokes) to authenticate identity. It is less accurate than some other biometric approaches (such as fingerprint recognition) but is popular in document authentication applications that have traditionally used written signatures. Some growth may be fueled by the adoption of pen-based devices (such as the Palm Pilot) that can double as a signature input tablet.

SIIA (Software & Information Industry Association)
A software industry trade association based in Washington, D.C.

SIM (subscriber identity module)
A small, programmable smart card containing a cellular service subscriber's identity key. The SIM contains codes to identify a subscriber to a digital mobile service and the details of the special services the subscriber has elected to use. The SIM may be fixed within the phone, or removable (enabling users to swap phones without changing their subscriptions). The SIM is the key to security on Global System for Mobile Communications (GSM) networks. In addition to GSM SIMs, two other types have been developed: the removable user identity module (R-UIM), which can be used in code division multiple access (CDMA) networks along with GSM ones, and the universal SIM (USIM), designed for use in third-generation (3G) networks. See GSM, smart card, R-UIM, CDMA, USIM and 3G.

SIMD (single instruction, multiple data)
A design for parallel computers characterized by instructions that can directly trigger a large number (in parallel) of data operations on different data. Vector processors fall into this category.

SIMM (single in-line memory module)
A small printed circuit board that plugs into a socket on a personal computer and increases the available random-access memory (RAM). See RAM.

simplex
A form of data transmission in which signals travel in one direction only. See half duplex and full duplex.

simulation
The use of a mathematical or computer representation of a physical system for the purpose of studying the effects of various condition scenarios, or forecasting outcomes. For example, historical information may be used to simulate future alternatives for supply chain operations design.

single-mode fiber
An optical fiber with a small core diameter, allowing the propagation of a single light path.

SIO (strategic information office)
A business-unit-neutral information office whose role is to communicate the importance of enterprise information management to all business units, generate support for these initiatives, negotiate organizational and technological issues across the enterprise, and enforce standards implementation and compliance at all levels of the enterprise. Members of the SIO should have in-depth knowledge of, and experience in, both business and technology, with at least one representative from senior management.

SIP (Session Initiation Protocol)
A protocol used to initiate interactive communication sessions of various types — including voice, video, chat, interactive games and virtual reality — between Internet users. A proposed standard of the Internet Engineering Task Force (IETF), the protocol is administered under the IETF's SIP Working Group.

SIPP (Stable Image Platform Program)
A program launched by Intel in June 2003. SIPP aims to give PC manufacturers and enterprises greater platform stability and advanced notice of future PC desktop and notebook changes.

SIS (student information system)
A system used in academic environments to enroll and register students, and to track student information such as prior transcripts, courses taken, grades received and progress toward a degree.

SITA (Societe Internationale de Telecommunications Aeronautiques)
A European provider of telecommunications and IT services to the airline industry, headquartered in Geneva.

Six Sigma
A quality philosophy designed to dramatically improve the way enterprises address customer and user requirements, while efficiently monitoring labor expenditures and controlling costs. It was first developed at Motorola, with a focus on manufacturing quality. The name derives from the goal of reducing out-of-specification product or service delivery to the Six Sigma (i.e., less than one-in-a-million) level. While ostensibly a quality program, Six Sigma is process-centric, rather than product-centric — all business practices are examined and steps are taken to reduce or eliminate variation.

SKU (stock-keeping unit)
A unique identification number that defines an item at the identifiable inventory level; for example, in retail applications, the SKU may designate style, size and color. A more detailed level would be at the serial number or unique identifier level.

SLA (service-level agreement)
An agreement that sets the expectations between a service provider and its customer. It describes the products or services to be delivered, the single point of contact for end-user problems and the metrics by which the effectiveness of the process is monitored and approved.

slave
A computer or device that is entirely controlled by another computer or device (the "master").

SLC (subscriber line charge)
An access charge paid by all telecommunications customers, established by the Federal Communications Commission to help local-exchange carriers pay for their installed network infrastructure and new development after the split-up of AT&T in 1984.

SLI (system-level integration)
A type of integrated circuit (also called a "system on a chip," or "SOC") that is dedicated to a specific application, and that contains a computing engine, memory and logic on a single chip.

SLIP (Serial Line Internet Protocol)
A protocol used for communication over an Internet Protocol (IP) network using a serial line (such as telephone line, for dial-up remote access). SLIP is defined in request for comment 1055 from the Internet Engineering Task Force. An enhanced version of SLIP is provided by the Point-to-Point Protocol (PPP). See PPP.

SLM (service-level management)
The ongoing process of using service-level agreements (SLAs) to maintain high quality in the provision of services — and to ensure that service-level objectives (SLOs) and performance meet the changing needs of the recipient's business — through continuous improvement of service activities, functions and processes. See SLA and SLO.

SLM (software license management)
A mechanism for systematically ensuring compliance with vendors' software license restrictions (for example, maximum users or maximum nodes).

SLO (service-level objective)
A goal defined in a service-level agreements (SLAs). SLOs are the objectives that must be achieved — for each service activity, function and process — to provide the best opportunity for service recipient success. See SLA.

SLR (Scalable Linear Recording)
A quarter-inch tape format developed by storage vendor Tanberg Data.

SMART (Self-Monitoring Analysis and Reporting Technology)
A storage technology standard. Disk drives incorporating SMART technology can monitor operating conditions and predict near-term degradation or fault conditions.

smart card
A plastic card that contains a memory chip and, optionally, a microprocesser. Smart cards with microprocessors can add, delete and manipulate information on the card. Those that contain only a memory chips, such as phone cards, can only add information. By maintaining all necessary functions and information on the card, smart cards do not require access to remote databases.

smartphone
A large-screen, voice-centric handheld device designed to offer complete phone functions while simultaneously functioning as a personal digital assistant (PDA). See enhanced phone and PDA.

SMB (Server Message Block)
A protocol designed to enable PCs to share files and printers over a network. It was developed by IBM, Microsoft and Intel in the 1980s.

SMBs (small and midsize businesses)
Businesses which, due to their size, have different IT requirements — and often face different IT challenges — than large enterprises, and whose IT resources (usually budget and staff) are often highly constrained. For the purposes of its research, Gartner defines SMBs using the following approximate size categories:

SMDS (Switched Multimegabit Data Service)
A high-volume, high-speed, switched digital communications service supporting speeds ranging from 1.544 megabits per second (Mbps) to 45 Mbps (with 155 Mbps possible in the future). It is based on the Institute of Electrical and Electronics Engineers' 802.6 standard for metropolitan-area networks (MANs). See MAN.

SME (small-to-midsize enterprise)
Another name for an SMB — see SMBs (small and midsize businesses).

SMIL (Synchronized Multimedia Integration Language)
One of the first four Extensible Markup Language (XML) specifications, approved by the Worldwide Web Consortium (W3C) in 1998, along with XML, Document Object Model and Mathematical Markup Language. The primary goal of SMIL is to decrease the bandwidth required to transmit television-like multimedia content through the Web. If adopted, SMIL will greatly enhance the ability of commercial content providers to bring television-like consumer content to the Web. See XML and W3C.

S/MIME (Secure Multipurpose Internet Messaging Extensions)
An e-mail security standard promoted by RSA Security. The S/MIME method for protecting and digitally signing e-mail encapsulates a message within a Multipurpose Internet Messaging Extensions (MIME) envelope and uses RSA's Public Key Cryptography Standard No. 7 (PKCS #7) to encrypt it. S/MIME specifies that X.509 certificates validate the correspondent's public keys and electronic signatures. See RSA, MIME, PKCS and X.509.

SMP (symmetric multiprocessing)
A multiprocessor architecture in which all processors are identical, share memory and execute both user and operating-system code.

SMR (specialized mobile radio)
A wireless communications technology that competes with analog cellular services. In an SMR system, the base station equipment supplier is the licensee of the transmitters. Users have access to the multiple channels of the network rather than the limited number of channels of a private mobile radio network. Many users share all of the available channels on a "first come, first served" basis.

SMS (Short Message Service)
A bidirectional paging function that is built into Global System for Telecommunications (GSM) systems. Each message can be up to 160 characters long. The network stores messages for several days (typically a maximum of 72 hours) and attempts to deliver the messages whenever the portable phone is switched on. Confirmation of receipt is available as an option in some networks.

SMS (system-managed storage)
A architectural concept for the attachment, management and reconfiguration of secondary storage. Among the basic design goals of SMS is the separation of logical-device management from physical-device management.

SMS (Systems Management Server)
A system management software product from Microsoft. It is used for distributing software, monitoring and analyzing network usage, and performing a variety of other network administration functions.

SMT (surface mount technology)
An integrated-circuit mounting system that uses flat pads instead of pins, eliminating the need to drill boards and making automated mounting easier.

SMTP (Simple Mail Transfer Protocol)
A messaging protocol governing e-mail transmission in Transmission Control Protocol/Internet Protocol (TCP/IP) networks. It is a server-to-server protocol that supports only text and cannot handle attachments. See TCP/IP.

SNA (Systems Network Architecture)
An IBM-developed network architecture, with layers similar to those of the Open Systems Interconnection (OSI) network reference model (see OSI). The layers isolate applications from system network services, enabling users to write applications independent of the lower networking layers.

SNAP (System Network Assurance Program)
A security industry certification program established by the SANS Institute. It consists of a standard series of briefings, courses and tasks used to demonstrate a more-detailed technical body of knowledge.

SNIA (Storage Networking Industry Association)
A storage network trade association headquartered in San Francisco.

sniffer
A network management tool that monitors data packets on a network to help administrators ensure message integrity and service quality.

SNMP (Simple Network Management Protocol)
A Transmission Control Protocol/Internet Protocol (TCP/IP) protocol governing network management and the monitoring of network devices. Strictly speaking, SNMP is the Management Information Base (MIB) described in the SNMP standard; extensions to this MIB proposed by the Electronic Messaging Association permit the monitoring and reporting of all conforming messaging components through standard SNMP management tools for network components.

SNOMED (Systematized Nomenclature of Medicine)
A nomenclature created by the College of American Pathologists (CAP) for use in pathology. SNOMED has gradually been extended to cover other domains of medicine. The SNOMED controlled medical vocabulary (CMV) contains over 150,000 terms and includes coverage for numerous medical specialties. The most recent versions released by CAP's SNOMED division are SNOMED Clinical Terms (SNOMED CT) and SNOMED Reference Terminology (SNOMED RT). See CMV, SNOMED CT and SNOMED RT.

SNOMED CT (Systematized Nomenclature of Medicine Clinical Terms)
A version of the Systemized Nomenclature of Medicine (SNOMED) controlled medical vocabulary (CMV) released in January 2002 by the College of American Pathologists' SNOMED division. It combines the content and structure of the SNOMED Reference Terminology (SNOMED RT) CMV with version 3 of the Clinical Terms CMV from U.K. National Health Service. See SNOMED and SNOMED RT.

SNOMED RT (Systematized Nomenclature of Medicine Reference Terminology)
A version of the Systemized Nomenclature of Medicine (SNOMED) controlled medical vocabulary released in January 2002 by the College of American Pathologists' SNOMED division. SNOMED RT was designed to help aggregate and integrate medical information within electronic medical records. See SNOMED.

SNR (signal-to-noise ratio)
The power of a signal relative to channel noise (that is, interference).

SOA (service-oriented architecture)
An application topology in which the business logic of the application is organized in modules (services) with clear identity, purpose and programmatic-access interfaces. Services behave as "black boxes": Their internal design is independent of the nature and purpose of the requestor. In SOA, data and business logic are encapsulated in modular business components with documented interfaces. This clarifies design and facilitates incremental development and future extensions. An SOA application can also be integrated with heterogeneous, external legacy and purchased applications more easily than a monolithic, non-SOA application can.

SOAP (Simple Object Access Protocol)
A protocol introduced by a group of vendors led by Microsoft. Designed to be simple, it creates transparent mapping of the Distributed Component Object Model (DCOM) interface definition language and Extensible Markup Language (XML) definitions. It provides the key transport technology for Web services, the next-generation paradigm for delivering applications as a set of Internet-enabled services. See DCOM, XML and Web services.

socket
A concept used as part of the interprocess communications model defined in the Unix and Linux operating systems. A socket specifies the end points of a two-way channel that enables processes to exchange information.

SOCKS
An Internet Engineering Task Force standard for IP-based security and policy management (the name is short for "socket server"). SOCKS enables administrator to set user-access policies based on specific protocols, such as Hypertext Transport Protocol.

SOD (statement of direction)
A vendor's announcement of future plans.

SODA (service-oriented development of applications)
The use of software services to create applications. Software services are components that allow a developer to create programmatic interfaces that can access underlying platform models, such as .NET or Java 2 Enterprise Edition (J2EE), without having to be specific to any single model. See .NET and J2EE.

softswitch
A type of network-switching technology. Softswitches are software-based products used to control communications networks.

software
Programs that control computer hardware. The two primary categories are system software (which governs the workings of the computer itself, such as the operating system and utilities) and application software (which performs specific tasks for the user, such as word processing, spreadsheets and accounts payable).

software maintenance
Updating software, adding new functions, fixing bugs and solving problems. Technology vendors often sell a maintenance contract with their software. This contract is usually calculated as an annual fee based on some percentage of the total software cost. It generally provides for overall support and maintenance of a software product, including applications. Support may include telephone assistance time as well.

software token
A software component that restricts the use of a specific ID/password combination to the machines on which the token is installed. Software tokens can be installed over the Internet on additional machines for a single session, or semipermanently, by providing the token server with the answers to a randomly ordered set of questions defined by the user at the time he or she initially enrolled in the authentication system. Such questions might include, "What is your mother's maiden name?" or "What was your roommate's nickname in your first year of college?"

SOHO (small office/home office)
A market segment for office equipment or computing peripherals (such as printers or copiers). Products targeted to the SOHO market tend to be lower in price and functionality than those designed to support large, corporate office environments.

SOI (silicon on insulator)
A type of integrated circuit substrate material that features an insulating oxide layer on top of the silicon wafer, and another silicon layer on top of the oxide. Advantages over previous generations of substrate materials include lower power consumption and faster performance.

solid-state
A general descriptive term for electronic components (such as semiconductors) that control current without the use of moving parts.

SONET (Synchronous Optical Network)
A International Telecommunications Union standard for high-speed communications over fiber-optic networks. It offers synchronous transmission at speeds up to multigigabit rates — defined at various "Optical Carrier" (OC) levels (see OC-N) — and includes features to enable multivendor interoperability, improved troubleshooting and network survivability. As standard that operates at Layer 1 of the Open Systems Interconnection (OSI) network model, it is a foundation for Broadband Integrated Services Digital Network (B-ISDN) services. See OSI and B-ISDN.

S&OP (sales and operations planning)
A formal planning process used to determine the sales and operations strategy that best meets all aspects of the enterprise's objectives. The SOP process mediates sales, marketing, finance, operations and logistics objectives to formulate a single, achievable plan for the near-term — usually under one year.

SOP 98-1 (Statement of Position 98-1)
A U.S. standard used to account for the cost of developing and maintaining software in-house. Under SOP-98-1, approved by the American Institute of Certified Public Accountants 1998, legacy software should be accounted for as an internal maintenance expense — but if a company significantly enhances a system's functionality, that work may be capitalized.

source routing
A technique used in local-area networks (LANs) in which the source of the frame specifies the route that the frame has to follow; the source furnishes a routing information field that designates the entire route to the destination.

sourcing
The procurement of resources — whether from internal or external sources — to accomplish business objectives. Sourcing purely from external sources is known as "outsourcing" (see outsourcing).

sourcing strategy
The set of scenarios, plans, directives and decisions that define and integrate the internal and external resources required to fulfill an enterprise's business objectives.

SOW (statement of work)
A document that provides comprehensive descriptions of required services — along with realistic information concerning the current environment — to ensure that vendors deliver what the enterprise needs at the price that has been negotiated. The essential elements of a statement of work include:

space segment
The segment of a satellite communications system that includes the satellites themselves, and the tracking, monitoring and control functions associated with them. It excludes any ground equipment.

spam
Electronic messages (such as electronic mail, newsgroup or bulletin board messages) flooded to many users indiscriminately. The term is most commonly used in reference to unsolicited commercial e-mail.

spanning tree
A technique used for bridging local-area networks without loops, as defined in the Institute of Electrical and Electronics Engineers' 802.1d standard. The spanning-tree algorithm ensures that only one path connects any pair of stations, selecting one bridge as the root bridge from which all paths are considered to radiate.

SPARC (Scalable Processor Architecture)
A reduced instruction set computer (RISC) architecture developed by Sun Microsystems and used in the Sun workstation family. SPARC chips are available from several semiconductor manufacturers, as Sun positions SPARC as a de facto standard.

SPC (statistical process control)
Maintaining or improving process capability by employing statistical techniques to analyze process outputs and provide feedback for process control loops. See process control.

speakerphone
A telephone device that has a speaker/microphone unit, allowing hands-free conversation.

speaker verification
A biometrics-based alternative to typed passwords or personal identification numbers. A computer verifies the identity of an individual by matching his or her spoken voice to an electronically captured voice sample (analogous to a unique fingerprint).

SPEC (System Performance Evaluation Cooperative)
A vendor consortium that selects and standardizes benchmark programs submitted by members or others, for the purpose of rating and comparing the performance of processors.

SPECfp (SPEC floating point)
A benchmark established by the System Performance Evaluation Cooperative (SPEC). It measures processor speed at handling floating-point operations. See SPEC.

SPECint (SPEC integer)
A System Performance Evaluation Cooperative (SPEC) benchmark to measure the integer performance of a processor. See SPEC.

spectrum
A continuous range of frequencies, usually wide in extent, within which waves have some specific common characteristics.

speech circuit
A circuit designed for the transmission of speech, either analog or encoded, but which can also be used for data transmission or telegraphy.

speech recognition
A computer's ability to convert spoken input into text, or to interpret spoken commands (also known as or "automatic speech recognition" or "voice recognition"). Special software is used to digitize vocal sounds and compares them to a library of sound patterns. When matches are found, the computer can recognize those words as though they had been typed on a keyboard. Applications for speech recognition include dictation software and interactive voice response (IVR) systems. The technology generally falls into three categories along a continuum:

speed dialing
A telephone feature that enables phone numbers to be stored in advance, so that they can be dialed automatically by entering a short (one- to three-digit) code, or by pushing a special button on the handset.

SPI (software process improvement)
The practice of continuously improving an enterprise's software development processes, typically through the use of a formal methodology, such as the Software Engineering Institute's Capability Maturity Model (CMM). See CMM.

spider
A piece of software (also called a Web crawler) designed to follow hyperlinks to their completion, and return information on Internet addresses passed.

SPIN (Software Process Improvement Network)
A best-practices group run by the Software Engineering Institute (SEI) that provides hands-on experience to IT professionals. See SEI.

splitter
A simple device that takes one input and sends it to several identical ports without amplification. Splitters are commonly used residentially for sharing telephone lines between handsets and modems, or for using two televisions on one antenna or cable point.

SPO (service process optimization)
Software designed to track and allocate the major resources of service companies or departments — people, intellectual capital and time. Most SPO applications address of six core areas of functionality:

Professional services administration (PSA) is a related term, but one that applies only to external service providers (ESPs). SPO applies to internal service departments as well as ESPs. See PSA.

spooling
Temporary storage of batch data until it is ready to be handled (for example, by a processor or printer).

spot beam
A satellite signal that is concentrated on a small geographic area.

SPP (service parts planning)
A specific aspect of supply chain planning (SCP) dealing with parts used to repair or maintain products (also known as "spare-parts planning"). See SCP.

spread spectrum
A technology used in radio transmission, enabling multiple signals to be broadcast simultaneously over a single frequency band. Forms include direct-sequence spread spectrum (DSSS) and frequency-hopping spread spectrum (FHSS), both of which are commonly used in wireless local-area networks (WLANs). See DSSS, FHSS and WLAN.

SPSS (Statistical Package for the Social Sciences)
A statistical analysis software package invented in 1968, which became the founding product of Chicago-based analytical-software firm SPSS, Inc.

SPX (Sequenced Packet Exchange)
A Novell NetWare session-based communications protocol used to govern the transport of messages across a network. It is designed to provide reliable end-to-end data transport, including error detection between two end-user devices.

SQL (Structured Query Language)
A relational data language that provides a consistent, English-keyword-oriented set of facilities for data querying, definition, manipulation and control. It is a programmed interface to relational database management systems (RDBMSs). IBM introduced SQL as the main external interface to its experimental RDBMS, System R, which it developed in the 1970s. SQL statements include:

SQL statements are called "dynamic" when they are not completely specified until the program is executed, and "static" when they are completely specified when the program is compiled. SQL is precise, because it is based on predicate logic, but is difficult for average users to deal with, and its most fruitful position is as a protocol for software-to-software connectivity, rather than for human-to-software access.

SRAM (static random-access memory)
A category of random-access memory (RAM) that is volatile (that is, does not retain information when the power is turned off), and that has a minimum of four transistors per memory cell. See RAM.

SRDF (Symmetrix Remote Data Facility)
An EMC storage feature that provides controller-to-controller remote-copy capability.

SRM (supplier relationship management)
A systematic approach to supplier evaluation, selection and ongoing relationship management, with the goal of cutting the costs of goods and services and boosting profits. SRM spans functional areas and enterprise boundaries, providing important decision support processes and functions to purchasing departments and key decision makers within the supply chain. It uses an extended-enterprise approach to squeeze waste out of the supply chain and to re-engineer the processes that link buyers and suppliers together.

SS7 (Signaling System 7)
The equivalent of a "central nervous system" for the public switched telephone network (PSTN). It is used to control the PSTN and facilitate intelligent network (IN) capabilities (see IN). SS7 enables:

SSA (Serial Storage Architecture)
An IBM architecture for disk subsystems. For most purposes, it is a single-source, proprietary interface, especially useful for users who have standardized on RS/6000 systems with applications that require very high data rates that are not particularly cache-friendly.

SSA (System Software Associates)
An enterprise resource planning (ERP) software vendor, headquartered in Chicago. Once formally known as System Software Associates, the company's full name became SSA Global Technologies following a corporate restructuring in 2000.

SSC (shared service center)
A process-driven, technology-leveraged service delivery facility set up within an enterprise to provide expert staff, tools and procedures to foster continuous improvement. As a result of globalization and the rise of decentralized, "virtual" enterprises, SSCs have emerged as an efficient and cost-effective service delivery model for a variety of business processes. The idea behind SSCs is to centralize routine service and administrative activities — such as human resources and procurement — that would otherwise be replicated in multiple locations.

SSD (solid-state disk)
A storage device with no moving parts. It typically includes one or more circuit boards loaded with memory chips, and a controller that presents a standard disk drive interface to the computer system.

SSL (Secure Sockets Layer)
An Internet security standard developed by Netscape Communications. SSL offers session-level security — that is, after a secure session has been initiated, all information transmitted over the Internet during that session is encrypted. SSL also offers features such as server and client authentication as well as message integrity.

SSO (single sign-on)
A term used to describe technology that enables a user to access multiple computer platforms (usually a set of hosts on the same network) or application systems after being authenticated just one time.

SSP (storage service provider)
A company that provides computer storage capacity and management services. In addition to the storage itself, SSPs typically offer periodic backup and archiving, and some offer to consolidate data from multiple enterprise locations so that all locations can share the data effectively.

stalking horse
A conceptual model under which statements are posited, or ideas are advanced, for the purposes of testing out new concepts and stimulating dialogue about them.

standard
A specification or practice that is widely accepted by users and adopted by multiple vendors. Standards are critical to the compatibility of hardware, software and communications technologies. They provide specifications to vendors that enable them to create products that will work together. De jure standards are developed by internationally or nationally recognized standards bodies. De facto standards are created by vendors under a proprietary process, but are widely adopted by other vendors and thereby achieve "standard" status.

star topology
A network topology in which each station is connected to a central station by a point-to-point link, and communicates with all other stations through the central one.

start-stop
A type of data transmission in which each group of code elements corresponding to a transmitted character is preceded by a start signal (which serves to prepare the receiving mechanism for the reception and registration of character) and is followed by a stop signal (which serves to bring the receiving mechanism to rest in preparation for the reception of the next character).

stateful
A term describing technology that maintains, or refers to, information regarding the "state" of a network session (such as source and destination address of packets delivered as part of that session, and the protocol used). Some firewalls or other intrusion detection technologies are said to use "stateful" packet inspection if they maintain awareness of the state of a network session, and reject or accept certain network packets based on that information.

stateless
A term describing a system or technology that operates without regard to information concerning "state" of a communication session (such as source and destination address of all packets delivered as part of that session, and the protocol used). A stateless system or protocol does not maintain such state information from one transaction or request to the next.

station
One of the input or output points of a communications network. Examples include a telephone in a voice network, or the point where a computer interfaces to a data network (also called a node).

statistical multiplexing
A time division multiplexing (TDM) technique in which time slots are dynamically allocated on the basis of need — that is, slots are allocated to equipment that has data to be transmitted. See TDM.

STEP (Standard for the Exchange of Product Model Data)
An international standards effort for defining the exchange of complete, unambiguous product model data. The goal of STEP is not only neutral file exchange, but also to serve as the basis for implementing, sharing and archiving entire product databases.

stickiness
A term used to describe a Web site's ability to attract and hold visitors — or, more generally, the features of any product or service that help attract and retain customers.

STM (synchronous transfer mode)
A technique for multiplexing several circuits over transmission links and switches. In STM, time is divided into slots or buckets, and circuits are given time units whether or not they have any data to transmit. See ATM (asynchronous transfer mode).

STM (Synchronous Transport Module)
A system of fiber-optic transmission rates defined in the Synchronous Digital Hierarchy (SDH) scheme (see SDH). STM levels are the European equivalent of Synchronous Optical Network (SONET) Optical Carrier Level N (OC-N) hierarchy in North America (see SONET and OC-N). Like those of OC-N, levels in the STM hierarchy are ordered by the bit rate of their aggregated signals, with the number after "STS-" representing the multiple of the 155 megabit per second (Mbps) STM-1 foundation rate (compared to 51.84 Mbps OC-1 foundation rate of SONET). Above that, each level quadruples, as follows:

STM-1
A Synchronous Digital Hierarchy (SDH) specification for fiber-optic transmission at 155 megabits per second. STM-1 is the European equivalent of OC-3 in the North American Synchronous Optical Network (SONET) system. See STM (Synchronous Transport Module), SDH, SONET and OC-N.

STM-16
A Synchronous Digital Hierarchy (SDH) specification for fiber-optic transmission at 2.5 gigabits per second. STM-16 is the European equivalent of OC-48 in the North American Synchronous Optical Network (SONET) system. See STM (Synchronous Transport Module), SDH, SONET and OC-N.

STM-256
In the Synchronous Digital Hierarchy (SDH), transmission at approximately 40 gigabits per second. STM-256 is the European equivalent of OC-768 in the North American Synchronous Optical Network (SONET) system. See STM (Synchronous Transport Module), SDH, SONET and OC-N.

STM-4
A Synchronous Digital Hierarchy (SDH) specification for fiber-optic transmission at 622 megabits per second. STM-4 is the European equivalent of OC-12 in the North American Synchronous Optical Network (SONET) system. See STM (Synchronous Transport Module), SDH, SONET and OC-N.

STM-64
A Synchronous Digital Hierarchy (SDH) specification for fiber-optic transmission at an approximate rate of 10 gigabits per second. STM-64 is the European equivalent of OC-192 in the North American Synchronous Optical Network (SONET) system. See SONET and OC-N.

STN (super-twisted nematic)
A type of liquid crystal display (LCD) technology. See LCD.

stop word
A word ignored by a search engine. Different document bases and search engines might employ different stop words, although most stop-word lists include common conjunctions, articles and prepositions (such as "and," "or," "the," "a," and "of" in English-language documents). See search engine.

storage appliance
A type of computing appliance that provides data to, or manages data for, other network-connected computing devices. Unlike server appliances, storage appliances provide or manage data without an application context. This category of computing devices includes network-attached storage (NAS) and storage-area network (SAN) devices. See computing appliance, server appliance, NAS and SAN.

store and forward
A type of transmission wherein data is stored in an intermediate location before being transmitted over a network.

stored procedure
A limited form of remote procedure call (RPC) that enables procedural code to be stored in a database management system (DBMS). The DBMS provides a facility for storing procedural code associated with the database, and enforces its use during any database operation. See RPC and DBMS.

STP (shielded twisted pair)
A pair of twisted transmission wires with a metallic shield to minimize interference.

STP (straight-through processing)
A system configuration in which a transaction (such as a payment, a trade or a change to a residential phone service) is entered only once. Thereafter, it proceeds in an automated fashion through the rest of its life cycle, which may include dozens of steps in different application systems in various locations. The goal is to avoid re-keying information, thereby reducing input errors and shortening the time to completion.

strategic sourcing
The dynamic delivery of internal and external business- or IT-oriented resources and services to meet business objectives. Strategic sourcing enables businesses to manage innovation and to deliver process and services effectively and efficiently, both to the internal organization and to business partners, clients and other external constituencies.

stream cipher
An old concept for encoding data, originally implemented with simple electromechanical or electrical circuits. A modern-day example of a stream cipher is Rivest Cipher 4 (RC4). Stream ciphers work on a serial bit stream — rather than a block of data, like a block cipher — and are thus naturally suited for electronic transmission of data. See RC4 and block cipher.

streaming
One-way (either point-to-point or broadcast to multiple receivers) transmission of video and audio content over the Internet or advanced wideband wireless networks.

structured analysis and design
A traditional, process-oriented approach to software system analysis and design (also known as "structured analysis/structured design," or "SA/SD"). Structured analysis and design uses a process-based methodology to ensure that designers focus on requirements definition, business process analysis and data modeling before proceeding to the design and construction phases of development.

STS (Synchronous Transport Signal)
A hierarchy of transmission levels for electrical signaling in Synchronous Optical Network (SONET) networks. STS levels are the "electrical equivalent" of SONET optical carrier (OC) levels — that is, they are defined for electrical signals converted to or from the optical ones (see SONET and OC-N). As such, the data rate for each STS level is identical to its corresponding OC level, as follows:

subnet
A portion of a network that shares the same network address as another portion (although it may be physically independent of that portion), and that is distinguished by a subnet number.

subportal
A commercial or enterprise portal that provides highly targeted aggregate content and interactive capabilities, and focuses on a more narrowly defined segment than a regular, general-interest portal. Subportals are hybrid environments in that they can be deployed as intranet or Internet solutions, or a combination of both. See portal.

suite
A group of programs designed to work together, and which often use the same underlying architecture.

SunOS
A older version of the Unix operating system from Sun Microsystems. SunOS was the precursor to Solaris.

supercomputer
A high-performance computing (HPC) system designed for applications or commercial functions that require extensive and rapid computational capabilities. Supercomputer technologies include vector computing, superscalar symmetric-multiprocessing and massively parallel processing (MPP). Applications that lend themselves to the supercomputer platform include atmospheric simulation, nuclear physics, and high-level decision support and online analysis. See HPC and MPP.

Supranet
A Gartner term describing the emerging, ubiquitous network infrastructure that links the "e-world" (the world of electronic devices, such as computers, phones and televisions) and the "p-world" (the physical world of paper, houses, people, vehicles and other objects) within natural human interactions. The Supranet is enabled by four key phenomena:

SVA (Shared Virtual Array)
A direct-access storage device (DASD) product introduced by Storage Technology (StorageTek) in 1999. SVA is based on the same technology as the RAMAC Virtual Array, an IBM-branded storage system for which StorageTek served as the original equipment manufacturer.

SVC (switched virtual circuit)
A virtual circuit set up on a network on a call-by-call basis. Unlike a permanent virtual circuit (PVC), an SVC provides only a temporary connection. See PVC and virtual circuit.

SVG (Scalable Vector Graphics)
A graphics specification form the World Wide Web Consortium (W3C). SVG is a modularized language that can be used to describe two-dimensional graphics in Extensible Markup Language (XML). See W3C and XML.

SVGA (Super Video Graphics Array)
A display standard defined by the Video Electronics Standards Association. It provides higher resolution than the 640 x 480 Video Graphics Array (VGA) standard, and supports as many as 16 million colors, depending on the computer system and amount of available memory. See VGA

SVID (System V Interface Definition)
The specifications for Unix System V, set by AT&T in the 1980s.

SVPCo (Small Value Payments Co.)
A banking consortium, formed in July 1998, that is governed by 12 large U.S. banks and that plans to extend its board to 20 members. SVPCo is concentrating on Electronic Check Presentment (ECP), which requires cooperation from many banks in order to succeed.

SVR4 (System V Release 4)
The fourth release of AT&T's System V Unix operating system, introduced in 1989.

SWIFT (Society for Worldwide Interbank Financial Telecommunication)
A self-describing messaging format used in the banking and finance industry to support electronic funds transfer. SWIFT is also the name of the format's creator, an organization that provides messaging and transaction-processing services to member banks and other financial organizations, including brokers, securities depositories, clearing organizations and stock exchanges.

switch
A device that makes, breaks, or changes the connections in an electrical circuit. As a form of communications technology, switches are used to control network traffic.

Switched 56
A low-cost alternative to private digital lines for data applications. Switched 56 technology provides reliable data transmission over a public switched network at data rates of up to 56 Kbps.

switching
The establishment of a transmission path from a particular inlet to a particular outlet, within a group of such inlets and outlets.

switching matrix
The portion of a switch architecture where input and output leads meet, any pair of which may be connected to establish a through circuit.

Symbian
A joint venture launched in 1998 by Psion, Ericsson, Nokia and Motorola to develop Psion's EPOC 32 operating system into a real-time operating system for handheld phones and PDAs. Matsushita, NTT DoCoMo, Siemens and Sun Microsystems have since joined. Its first products were released in 1999. Symbian has released reference designs and a software developer's kit.

synchronization
Establishment of common timing between sending and receiving equipment.

synchronous
Having a constant time interval between successive bits, characters or events. Synchronous transmission uses no redundant information to identify the beginning and end of characters, and is faster and more efficient than asynchronous transmission, which uses start and stop bits. See asynchronous.

SyncML (Synchronization Markup Language)
A standard developed to provided a uniform data synchronization protocol — operating on any device, over any network — among various vendors' mobile products. The SyncML initiative is sponsored by Ericsson, IBM, Lotus, Matsushita, Motorola, Nokia, Openwave, Starfish Software and Symbian.

syntax
The format or grammar used in data coding or transmission. For example, for a network message, syntax governs features such as field lengths and delineators, headers and footers, and optional fields.

sysplex
A system complex of closely coupled processors in an IBM clustered-computing system. See Parallel Sysplex.

System/370
The family of IBM mainframe-class computers that preceded the System/390. See System/390.

System/390
IBM's processor family announced in September 1990, which replaced the System/370 family. System/390 (S/390) family included the ES/9000 mainframes. IBM re-branded and upgraded its S/390 mainframe-class computers as the "zSeries" in 2000. See zSeries.

system integration
The process of creating a complex information system. This process may include designing or building a customized architecture or application, and integrating it with new or legacy hardware, packaged and custom software, and communications. Most enterprises rely on an external contractor for program management of most or all phases of system development (see system integrator).

system integrator
An organization or an individual that performs system integration. Major system integration projects often require the assistance of a specialty firm that has the resources and expertise to manage a project plan that could last over several months or even years. This external vendor generally assumes a high degree of the project's risks.

system management
Any of a number of "housekeeping" activities intended to maintain or correct the operation of a computer system. Included are such routine but critical processes as hardware diagnostics, software distribution, backup and recovery, file and disk integrity checking, and virus scanning.

System V
A Unix operating system introduced by AT&T in 1983.