S

S-100           bus. An early system bus (circa 1976) introduced by MITS,
                Inc., as part of the Altair computer.
SAA             Systems Applications Architecture. SAA provides a framework
                for the development of consistent application across the
                future offerings of the major IBM computing environments.
                The elements of SAA are : CUA, CPI, CCS.
SADT            Structured Analysis and Design Technique. This is a
                diagrammatic method for organizing and presenting information-
                processing requirements.
SAM             Sequential Access Method.
SAM             System Administration Manager.
SAP             Serial Access Paradigm.
SAP             Service Access Point. The subaddress used to uniquely 
                identify a particular link between two protocol layers in a 
                specific system.
SAP             Service Advertising Protocol.
SA/SD           Structure Analysis / Structure Design.
SASD            Structure Analysis / Structure Design.
SASE            Specific Application Service Element. A collection of 
                protocol entities forming part of the application layer 
                responsible for providing various specific application 
                services, such as file transfer and job transfer.
SB              Sound Blaster. The most important characteristics of this
                card is its integrated sampling capablity, with one digital
                audio channel for recording and playing nature sounds, music,
                or speech.
SBI             Sound Blaster Instrument. A music file format introduced by
                Creative Labs.
SBT             Surface Barrier Transistor.
SCC             Secure Computing Corporation.
SCI             Scalable Coherent Interface. The IEEE standard specifies that 
                sharing caches be linked together (in software).
SCO             the Santa Cruz Operation.
SCR             Silicon-Controlled Rectifier.
SCSI            Small Computer Systems Interface. A system-independent
                expansion bus typically used to connect hard disks, tape
                drives, and CD-ROMs to a computer. A host adapter connects
                the SCSI bus to the computer's own bus. Also handles 
		floppydisk, printers, worm, scanners. See also ESDI, IDE.
SDA             Swappable Data Area. The portion of the DOS data segment
                containing all of the variables used internally by DOS to
                record the state of a function call in progress.
SDH             Synchronous Digital Hierachy.
SDK             Software Development Kit.
SDLC            Synchronous Data Link Control. A protocol developed by IBM
                for software applications and communicating devices operating
                in IBM's SNA. The protocol defines operations at the link
                level of communications, for example, the format of data
                frames exchanged between modems over a phone line.
SDM             Semantic Data Model. The SDM introduced the concepts of
                classes and subclasses into data modeling; hence, it was the
                initial source for many of the concepts that have since been
                incorporated into conceptual data models, including object-
                oriented models.
SDRAM           Synchronous Dynamic Random Access Memory.
SD-UX           Software Distributor - UniX
SE              Session Entity.
SEL             SELector.
SEQUEL          Structured English QUEry Language. Originally, SQL was called
                SEQUEL and was designed and implemented at IBM Research as
                the interface for an experimental relational database system
                called SYSTEM R.
SES             Scientific and Engineering Software.
SFT             System Fault Tolerance.
SFT             System File Table. A System File Table is a DOS-internal
                data structure used to maintain the state of an open file
                for the DOS 2+ handle functions, just as an FCB maintains the
                state for DOS 1.x functions.
SGML            Standard Generalized Markup Language. This is a standard for
                describing markup languages.
SGS             Status Group Select.
SHA		Secure Hash Algorithm. SHA is similar to MD5 and has been 
		issued by the US NIST as a federal standard.
SHISAM          Simple Hierarchical Indexed Sequential Access Method. A
                simple  variant of HISAM where a database contains only one
                segment type (the root segment).
SHSAM           Simple Hierarchical Sequencial Access Method. A simple
                variant of HSAM where a database contains only one segment
                type (the root segment).
SHTTP           Secure HyperText Transport Protocol. Secures documents that 
                comprise the transaction. Proponents include Enterprise 
                Integration Technologies and CommerceNet. Not widely 
                implemented but potentially more secure than SSL.
SI              Shift-In character.
SI              Source-Index register. A register in the 8088 microprocessor
                that holds a source index during various string operations.
SI              Subnet Identifier.
SIASEA          Single Instruction Array Single Execution Array.
SIC             Standard Industrial Classification.
SID		Sound Interface Device.
SIDF            System-Independent Data Format.
SIMD            Single Instruction stream Multiple Data stream. In Flynn's
                classification, the architectural category that is composed
                of computers with a single control unit and many processing
                elements; applies to most processor arrays.
SIGMOD          Special Intrest Group on Management Of Data.
SISD            Single Instruction stream Single Data stream. In Flynn's
                classification, the architectural category composed of
                ordinary (von Neumann) computers; there is only one CPU,
                which executes one instruction at the time and fetches or
                stores just one datum at the time.
SISSEA          Single Instruction Scalar Single Execution Array.
SISSES          Single Instruction Scalar Single Execution Scalar.
SIT             Simple Internet Transition.
SLC             Subscriber-Loop Carrier.
SLIP            Serial Line Internet Protocol.
SLT             Solid-Logic Technology.
SMAP            SendMail Application Proxy.
SMB             Server Message Block.
SMD             Storage Module Drive. Type of drive controller, used on VAX's 
                and some older model computers. 
                Example of drive - Fujitsu Eagles - 440 MB, 140+ pounds.
SMD             Surface Mounted Device.
SMDS            Switched Multimedia/Multi-Megabit Data Service.
SMIT            System Management Interface Tool.
SMP             Session Management Protocol.
SMP             Symmetric MultiProcessing.
SMS             Storage Management System.
SMS             System Management Server.
SMTP            Simple Mail Transfer Protocol. The application protocol in a 
                TCP/IP suite that is used to transfer mail between an 
                interconnected set of (native) electronic mail systems.
S/N             Signal-to-Noise ratio.
SNA             System Network Architecture. SNA is not a data communications
                protocol. It is a set of rules, procedures, and structures
                that encompasses IBM's data communications design philosophy.
                It is also part of an IBM corporate strategy, since it is the
                framework for future IBM data communications development.
SNADS           System Network Architecture Distribution Service. SNADS
                operates at the function management layer of SNA.
SNMP            Simple Network Management Protocol. The application protocol 
                in a TCP/IP suite used to send and retrieve 
                management-related information across a TCP/IP network.
SO              Shift-Out character.
SOA             Save Operating Area.
SOCRATES        System Of Cellular RAdio for Traffic Efficienty and Safety.
SOH             Start-Of-Heading character.
SOHO            Small Office/Home Office.
SOM             Self-Organizing Map.
SOM             Start Of Message.
SOM             System Object Model.
SONET           Synchronous Optical NETwork.
SOS             Silicon-On-Sapphire technology.
SP              Stack Pointer. A register that holds the address of the top
                element of a stack in memory, typically by automatically
                incrementing or decrementing the content of a stack register.
SPARC           Scalable Processor ARChitecture. A RISC architecture by Sun 
                Microsystems.
SPEC            System Performance and Evaluation Cooperative. Group founded
                by Apollo, Hewlett Packard, MIPS and Sun Microsystems to
                evaluate the performances of computers.
SPF             Shortest Path First. The algorithm used in 
                gateways/routers/intermediate systems to find the shortest 
                path between itself and all the other gateways in an 
                internetwork.
SPID            Service Provider IDentifications.
SPMD            Single Program, Multiple Data. A special case of MIMD, in 
                which all processors execute the same program, although at 
                any one time the instruction (and of course the data) can be 
                different in each processor due to data-dependent branches, 
                varying memory-access times, and so on.
SPOOL           Simultaneous Peripheral Operation OnLine.  The process of
                performing output to a slow peripheral such as a printer
                while other tasks continue running on the CPU.  This term
                dates back to mainframe days before the invention of
                timesharing.
SPX             Sequenced Packet eXchange. IPX seems to control the
                establishment of virtual circuits. See also IPX.
SQL             Structured Query Language. See also SEQUEL.
SQLCA           Structured Query Language Comminication Area. SQLCA serves as
                the common feedback area between the application program and
                DB2.
SQLDA           Structured Query Language Descriptor Area.The description of
                expected results in SQL is returned in an area called SQLDA.
SR              Set-Reset flip-flop. An asynchronous flip-flop having two
                inputs, S and R. Asserting S sets the flip-flop, asserting R
                clears it and asserting both S and R results in an
                unpredictable state.
SRAM            Static Random Access Memory. RAM which typically consists of
                one flip-flop per bit of memory.  Unlike DRAMs, static RAM
                retains its contents as long as power is applied. Because
                there is no need to refresh the contents of memory addresses
                which are read, SRAM is faster than DRAM, but it is more
                expensive and typically is available in much smaller sizes
                than DRAM because each bit occupies more space on the chip.
                See also DRAM.
SRM             Server Request Manager.
SRQ             Service ReQuest.
SS              Stack-Segment register. In the 8088 microprocessor, holds the
                base address of the stack segment.
SSAP            Session Service Access Point.
SSCP            Systems Services Control Point.
SSI             Small-Scale Integration. Characteristic of integrated
                circuits having only a few transistors on each chip.
SSL             Secure Sockets Layer. Secures the transaction channel. 
                Proponents include Netscape Communications. Used currently by 
                commercial businesses on the Internet.
SSP             System Status Panel.
Star-100        An early supercomputer (circa 1970) by Control Data
                Corporation.
STARAN          A bit-slice associative processor developed by Goodyear
                Aerospace (circa 1972) for associative-memory operations.
STB		Set-Top Box.
STB             STroBe Input. A handshake signal used by the 8255 PPI.
STD             Subscriber Trunk Dialing.
STEP            ISO STandard for the Exchange of Product model data.
STM             Sort-Term Memory.
STX             Start of TeXt.
SUB             SUBstitute character.
Sun SPARC       See SPARC.
SVC             SuperVisor Call.
SVGA            Super VGA. A video adapter capable of higher resolution
                (pixels and/or colors) than the 320x200x256 and 640x480x16
                which IBM's VGA adapter is capable of producing.  See also
                VESA.
SYN             SYNchronous idle character.
SYSOPR          SYStem OPeratoR. SYSOPR priviledge allows the holder to
                perform only console operator functions, with no access to the
                database.
SYSOPS          SYStem OPeratorS.
System/360      See IBM System/360.
System/370      See IBM System/370.
