SAA: Systems Application Architecture, (IBM)
SAC: Service Access Controller, (Solaris2.x) , (SUN Microsystems, Inc.).
SAF: Service Access Facility; Port managementservice contained in "Solaris 2.x", (SUNMicrosystems, Inc.). Replaces the 'getty' function, with additionalaccess controls.
SAP: (Acronym for a long German name) A companyfrom Germany that sells the leading suite of client-server business software.The US branch is called SAP America.
SAP: Service Access Point
SAPI: Service Access Point Identifier
SAR: Segmentation And Reassembly, (A Cell orPacket technology service)
SAS: Single Attachment Station, (FDDI)
SASE: Specific Application Service Element
SCC: Super Computer Center
SCO: Santa Cruz Operation
SCPC: Single Channel Per Carrier; access methodfor a large number of signals to go through a single transponder.
SCPS: Space Communications Protocol Standards;a standards initiative taken on by NASA and DoD.
SCR: Sustained Cell Rate, (ATM)
SCSI: Small Computer System Interface; SCSIwas originally called SASI for "Shugart Associates System Interface" beforeit became a standard. The original standard is now called "SCSI-1" to distinguishit from SCSI-2 and SCSI-3 whichinclude specifications of Wide SCSI (a 16 bit bus) and Fast SCSI (10 MB/stransfer). SCSI-1 has been standardised as ANSIX3.131-1986 and ISO/IEC 9316.
SCSI-2: Small Computer System Interface- version 2; SCSI-2 shares the original SCSI's asynchronousand synchronous modes and adds a "Fast SCSI" mode (<10MB/s) and "WideSCSI" (16 bit, <20MB/s or rarely 32 bit).
SCSI-3: Small Computer System Interface- version 3; An ongoing standardisation effort to extend the capabilitiesof SCSI-2. SCSI-3's goals are more devices on a bus(up to 32); faster data transfer; greater distances between devices (longercables); more device classes and command sets; structured documentation;and a structured protocol model.
In SCSI-2, data transmission is parallel (8, 16or 32 bit wide). This gets increasingly difficult with higher data ratesand longer
cables because of varying signal delays on different wires. Furthermore,wiring cost and drive power increases with wider data
words and higher speed. This has triggerer the move to serial interfacingin SCSI-3. By embedding clock information into a
serial data stream signal delay problems are eliminated. Driving asingle signal also consumes less driving power and reduces
connector cost and size.
SCTE: Society of Cable TelecommunicationsEngineers
SDH: Synchronous Digital Hierarchy; The opticaldata rate, synchronization, and framing format chosen for the Europeanimplementation of B-ISDN -- analogous to SONETin the US and Japan. SDH is an international digital telecommunicationsnetwork hierarchy which standardizes transmission around the bit rate of51.84 megabits per second, which is also called STS-1.Mul-tiples of this bit rate comprise higher bit rate streams. Thus STS-3is 3 times STS-1, STS-12 is 12times STS-1, and so on. STS-3is the lowest bit rate expected to carry ATM traffic,and is also referred to as STS-1 (Synchronous TransportModule-Level 1).
SDM: Space Division Multiplexing
SDRAM: Synchronous Dynamic RAM
SDRC: Structural Dynamics Research Corporation
SDS: Scientific Data Systems; A computer manufacturerwhose computers were used at the birth of the Internet; a SDS Sigma-7 computerat UCLA sent the first two characters to an SDS 940 system at the StanfordResearch Institute.
SDSL: Single line Digital Subscriber Line:HDSL over a single telephone line. This name has beenadopted by a single manufacturer, not a standards group, and may not stick.It important to distinguish, however, as SDSL operates over POTSand would be suitable for symmetric services to premises of individualcustomers.
SDTV: Standard Definition Television; is adigital television system in which picture quality is approximately equivalentto the current NTSC television system. The ATVstandard will probably allow multiple SDTV programs. The quality will bebetter than NTSC in the respect that there will befewer NTSC artifacts such as "chroma crawl" and noise.Depending on the number of SDTV programs and the degree of action in thepicture, there may be visible motion artifacts that NTSCdoes not have.
SDU: Service Data Units; Have been known torefer to ATM53 byte cells.
SDV: Switched Digital Video
SDVN: Switched Digital Video Network
SEAL: Simple and Efficient Adaptation Layer;Also known as ATM Adaptation Layer type 5 (AAL5)
SEC: Securities and Exchange Commission
SECAM: Fr. Sequentiel Couleur Avec Memoire,(Sequential Color With Memory); European video standard with image format4:3, 625 lines, 50 Hz and 6 Mhz video bandwidth with a total 8 Mhz of videochannel width.
SEPP: Securee Encryption Payment Protocol;protocol for conducting secure credit card transactions over the Internet.Sponsored by Mastercard, working with IBM and Netscape; based on Netscapes'sSSL, (Secure Sockets Layer).
SET: Secure Electronnic Transactions; An accordset by Mastercard and Visa for Internet commerce; secure credit card transactionsover the Internet. Based on RSA encryption.
Set-top Box: An appliance originally usheredin by the CATVindustry, now providing additional data conversion utilities, such as MPEG-2decompression, and ATM packet reassembly.
SFS: Shared File System, (CRAYSoftware - UNICOS)
SGI: Silicon Graphics Inc. (SGI- Silicon Surf)
SGML: Standard Generalized Mark-up Language
S-HTTP: Secure HyperText Transport Protocol
SHVA: Satellite Home Viewer Act;
SID: Service ID
SIF: Standard Interchange format; Format forexchanging video images of 240 lines with 352 pixels each for NTSC,and 288 lines by 352 pixels for PAL and SECAM.At the nominal field rates of 60 and 50 fields/s, the two formats havethe same data rate.
SIMD: Single-Instruction, Multiple-Data
SLIP: Serial Line Internet Protocol
SMB: Server Message Block; The application-layerprotocol used by Microsoft's LANManager and Windows for Workgroups products. Runs over NetBEUI.
SMDS: Switched Multimegabit Digital Service
SMI: Structure of Management Information
SMIL: Syncronized Multimedia Integration Language(W3C)
SMP: Symmetrical Multi-Processing
SMPTE: Societyof Motion Picture and Television Engineers
SMTP: Simple Mail Transport Protocol
SNA: Systems Network Architecture, (IBM)
SNADS: SNA DistributionService; an IBMasynchronous distribution service that defines a set of rules to receive,route and send electronic mail in a network of systems. (IBM)
SNMP: Simple Network Management Protocol
SNMPv2: Simple Network Management Protocolversion 2
Socket: BSD Unix mechanismfor creating a virtual connection between processes.
Solaris: Both SysVR4and BSD versions of Unix provided by SUNMicrosystems, Inc., (SUN). Versions prior to2.0 were based on BSDUnix and were known as SunOS.Following version 2.0; Solaris was a combination of BSDandSysVR4.
SONET: Synchronous Optical NETwork; The opticaldata rate (seeOC-x rates), synchronization, and framing format chosen for the USand Japanese implementation of B-ISDN-- analogous to SDHin Europe.
SP3: Security Protocol at Layer 3
Spam; (or Spamming): An inappropriate attemptto use a mailing list, or USENET or other networked communications facilityas if it was a broadcast medium (which it is not) by sending the same messageto a large number of people who didn't ask for it. The term probably comesfrom a famous Monty Python skit which featured the word spam repeated overand over. The term may also have come from someone's low opinion of thefood product with the same name, which is generally perceived as a genericcontent-free waste of resources. (Spam is a registered trademark of HormelCorporation, for its processed meat product.)
Spectrum: A comprehensive multi-architecturenetwork management system - based on an 'inference engine' based virtualmodel of the network. (Cabletron Systems, Inc.)
Spectrum: An IEEEpublication. (IEEESpectrum)
SPF: Shortest Path First algorithm: Routingalgorithm that iterates on length of path to determine a shortest-pathspanning tree. Commonly used in link-staterouting algorithms. Sometimes called Dijkstra's algorithm. See alsolink-state routing algorithm.
Spread Spectrum: The term spreadspectrum defines a class of digital radio systems in which the occupiedbandwidth is considerably greater than the information rate. The techniquewas initially proposed for military use, where the difficulties of detectingor jamming such a signal made it an attractive choice for covert communication.The term code-division multiple access (CDMA) is oftenused in reference to spread spectrum systems and refers to the possibilityof transmitting several such signals in the same portion of spectrum byusing pseudorandom codes for each one. This can be achieved by either frequencyhopping (A series of pulses of carrier at different frequencies, in a predeterminedpattern) or direct sequence (A pseudorandom modulating binary waveformwhose symbol rate is a large multiple of the bit rate of the original bitstream) spread spectrum and provides an alternative to frequency divisionmultiple-access (FDMA) or time-division multiple access(TDMA) methods.
SPMD: Single Program Multiple Data
SQL: Structured Querey Language
SQR: Structured Querey Report
SRAM: Static Random Access Memory
SRM: Session and Resource Manager, (MPEG)
SSFT: Space Station File Transfer Protocol
SSL: Secure Socket Layer, (Netscape)
STB: Set-Top-Box, formerly of CATVfame, now more likely to gain more prominence through VoDsystems. My prediction is that the set-top-box will evolve into the household'snetwork hub. It may or may not retain all the MPEGdecoding/encoding responsibilities, whereas these may be offloaded to thehome computer.
STC: System Time Clock
STM: Synchronous Transfer Mode
store and forwardpacket switching: Packet-switching technique in which frames are completelyprocessed before being forwarded out the appropriate port. This processingincludes calculating the CRC and checking the destinationaddress. In addition, frames must be temporarily stored until network resources(such as an unused link) are available to forward the message. Contrastwith cut-through packet switching.
STP: Shielded Twisted Pair; shielded copperphone wire.
STS-1: Synchronous Transmission Structurelevel 1; The most often used framing and synchronization unit used forSONET, theframe is composed of 9 rows of 90 bytes each and takes 125 micro-secondsto deliver one complete frame; the bit rate, for STS-1, is therefore 51.84Mb/s.
STS-3: Synchronous Transmission Structurelevel 3; (seeSTS-1) has a bit rate of 155.52 Mb/s.
STT: Secure Transaction Technology; An E-Commerceprotocol developed by Microsoft for Visa.
SUN: Stanford University Network (SUN Microsystems,Inc.) Sun Microsystems' Home Page.
SunOS: BSD version of Unix provided by SUNMicrosystems, Inc., (SUN)
SVC: Switched Virtual Connection; An ATMlogical connection established between endpoints. An SVC is a connectionthat is set up automatically through signalling protocol. SVCs does notrequire the manual interaction needed to set up PVCsand, as such, are likely to be much more widely used. All higher layerprotocols operatring over ATM primarily uses SVCs.
SVGA: Super Video Graphics Array
SVR4: System V Release 4; version of SystemmV Unix
switch: 1. Network device that filters,forwards, and floods frames based on the destination address of each frame.The switch operates at the data link layerof the OSI model. 2. General term applied to an electronicor mechanical device that allows a connection to be established as necessaryand terminated when there is no longer a session to support.
SysV: System V Unix