Glossary of Terms
Article:  Andy Collinson
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Glossary of Terms:
Below is a common list of frequently used abbreviations. These terms are used throughout Circuit Exchange International, and also in the wider industries of electronics, computing, networking and telecommunications. Please note, there may be omissions or errors in the list. The index allows quick selection.


A A-D Analog to Digital AAL5 ATM Adaption Layer 5 ABR Available Bit Rate AC97 Audio Codec 97 ACIA Asynchronous Communications Interface Adapter ACK Acknowledge ACS Asynchronous Connection Server ACT Application Control Table ACU Automatic Calling Unit ADC Analog Digital Converter ADDMD Administrative Directory Management Domain ADMD Administrative Management Domain ADO ActiveX Data Object ADSL Asymmetric Digital Subscriber Line AGP Accelerated Graphics Port AGS Advanced Graphics System AI Artificial Intelligence ALT Application Load Table ALU Arithmetic and Logic Unit AM Access Method AMD American Micro Devices AMR Audio Modem Riser AMS Access Method Services ANR Automatic Network Routing ANS Advanced Network Services ANSI American National Standards Institute AP Access Point AP Automation Protocol APA All Points Addressable APDU Application Protocol Data Unit API Application Programming Interface ARP Address Resolution Protocol ARPA Advanced Research Projects Agency ARPANET Advanced Research Projects Agency Network ASC Accredited Standards Committee ASCII American Standard Code for Information Interchange ASE Application Service Element ASIC Application-Specific Integrated Circuit ASN Abstract Syntax Notation ASTs Asynchronous System Traps AT Advanced Technology ATM Adobe Type Manager ATM Asynchronous Transfer Mode AWG American Wire Gauge

B BASH Bourne-Again SHell BASIC Beginners All-Purpose Symbolic Instruction Code BBS Bulletin Board System BCC Block Check Character BCD Binary Coded Decimal BCF Bridge Control Facility BER Bit Error Rate BG BackGround BIOS Basic Input/Output System BIT Binary Digit BITNIC Bitnet Network Information Center BLOB Binary Large Object BMIC Bus Master Interface Controller BMP BitMaP BRI Basic Rate Interface BS Backspace / British Standard BSA Basic Service Area BSAM Basic Sequential Access Method BSC Binary Synchronous Communication BSD Berkeley Software Distribution BSDS BootStrap Data Set BSI British Standards Institute BYP Bypass

C CA Collision Avoidance CAD Computer Aided Design CAE Computer Aided Engineering CAT Computer Aided Testing CATV CAble TeleVision CBR Constant Bit Rate CBT Computer Based Training CCD Charge-Coupled Device CCIR International Radio Consultative Committee CCITT Comite Consultatif International Telegraphique et Telephonique CD Collision Detection CD Compact Disk CDDA Compact Disk - Digital Audio CDDI Copper Data Distribution Interface CDE Common Desktop Environment CDG Compact Disk - Graphic CDI Compact Disk Interactive CDROM Compact Disk ROM CDTV Commodore Total Vision CDXA Copmact Disk eXtended Architecture CENELEC Comité Européen de Normalisation Electrotechnique CERN Conseil Européen pour la Recherche Nucléaire CGA Colour Graphics Adapter CGI Common Gateway Interface CGI Computer Graphics Interface CGM Computer Graphics Metafile CHAP Challenge-Handshake Authentication Protocol CHL-I CHanneL Interface CHPID CHannel Path IDentifier CI Computer Interconnect CI Control Interval CIF Common Intermediate Format CMOS Complimentary Metal Oxide Semiconductor CMOT Common Management Information Protocol (CMOT) Over TCP/IP CMR Communications Resource Manager CMS Conversational Monitor System CMYK Cyan, Magenta, Yellow, Black CN Corporate Network CNC Computerized Numerical Control CNLP Connectionless Network Protocol CNM Communication Network Management CNMA Communication Network for Manufacturing Applications CNR Carrier-to-Noise-Ratio Codec Coder/Decoder COFF Common Object File Format COM Common Object Model CP Control Program CP-SVR Control Point to Server CP/M Control Program/Monitor (for Microcomputer) CPE Customer Premises Equipment CPI Characters Per Inch CPS Characters Per Second CPU Central Processing Unit CR Carriage Return CR Communication Region CRC Cyclic Redundancy Check CRJE Conversational Remote Job Entry CRS Computer Reservation System CRS Configuration Report Server CRT Cathode Ray Tube CSA Common System Area CSC Cross System Consistency CSDN Circuit Switched Data Network CSECT Control Section CSI Consolidated Software Inventory CSLIP Compressed SLIP CSMA/CA Carrier Sense Multiple Access with Collision Avoidance CSMA/CD Carrier Sense Multiple Access with Collision Detection CSP Control Sequence Prefix CSP Cross System Product CSPDN Circuit Switched Public Data Network CSS Cascading Style Sheet CST Computer Supported Telephony CSU Channel Service Unit CSU/DSU Channel Service Unit / Data Service Unit CT Continuous Tone CT2T Continuous Tone To Tape CTC Channel To Channel CTC CICS To CICS CTS Clear To Send

D D/A Digital/Analog DA Desk Accessory DAC Digital Analog Converter DAC Dual Attachment Concentrator DAI Distributed Artificial Intelligence DAM Direct Access Method DAP Directory Access Protocol DAP Document Application Profile DARPA Defense Advanced Research Projects Agency DAS Dual Attachment Station DASD Direct Access Storage Device DAT Digital Audio Tape DAT Dynamic Address Translation DB Database DBCS Double Byte Character Set DBMS DataBase Management System DBRT Directed Beam Refresh Terminal DC Data Cartridge DC Data Communication DCA Document Content Architecture DCAF Distributed Console Access Facility DCB Data Control Block DCB Disk Coprocessor Board DCC Diskette Controller Chip DCE Data Circuit terminating Equipment DCE Data Communications Equipment DCE Distributed Computing Environment DCI Display Control Interface DCL Digital Command Language DCS Desktop Color Separation DCT Destination Control Table DCT Discrete Cosine Transform DD Data Definition DDCMP Digital Data Communications Message Protocol DDCS Distributed Database Connecion Services/2 DDE Dynamic Data Exchange DDES Digital Data Exchange Specifications DDI Device Driver Interface DDK Driver Development Kit DDL Data Definition Language DDN Defense Data Network DECT Digital European Cordless Telephone DECUS Digital Equipment Computer Users Society DEL Delete DES Data Encryption Standard DF Direction Flag DHCP Dynamic Host Configuration Protocol DHTML Dynamic HTML DIA Document Interchange Architecture DIB Data Input Bus DIB Device Independent Bitmap DIFS Distributed coordination function InterFrame Space DIMM Dual Inline Memory Module DIP Dual Inline Package DIS Draft International Standard DISSOS Distributed Office Support System DIT Directory Information Tree DKI Driver Kernel Interface DL Data Length DLE Data Link Escape DLL Dynamic Link Library DMA Direct Memory Access DMCI Direct Memory Communications Interface DOS Disk Operating System DOS/VS Disk Operating System / Virtual Storage DOS/VSE Disk Operating System / Virtual Storage Extended DP Data Processing DP Draft Proposal DPA Document Printing Application DPF Data Private Facility DPI Dots Per Inch DPL Descriptor Privilege Level DPMS Display Power Management Signaling DRM Digital Radio Mondial DRM Digital Rights Media DRAM Dynamic Random Access Memory DRQ Data ReQuest

E E1 2,048 Mbps E3 34 Mbps EARN European Academic and Research Network EB Error Bell EB ExaByte (1,152,921,504,606846,976 bytes) EBAM Electronic Beam-Addressable Memory EBCD Extended Binary Coded Decimal EBCDIC Extended Binary Coded Decimal Interchange Code ECC Error Checking and Correction ECC Error Correction Code ECE Economic Commission for Europe ECF Enhanced Connectivity Facility ECITC European Committee fo IT Testing and Certification ECKD Extended Count-Key Data ECMA European Computer Manufacturers Association ECTUA European Counsil for Telecommunications Users Association EDC Enterprise Database Connectivity EDF Execution Diagnostic Facility EDG Electronic Dot Generation EDI Electronic Data Interchange EDIF Electronic Design Interchange Format EEMA European Electronic Mail Association EFT Electronic Funds Transfer EGA Enhanced Graphics Adapter EGP Exterior Gateway Protocol EHLLAPI Emulator High Level Language Applications Programming Interface EIB Execute Interface Block EIP Execute Interface Program EISA Extended Industry Standard Architecture ENQ Enquiry EOB End of Block EOC End of Cylinder EOF End of File EOJ End of Job EOP End of Procedure EOT End of Transmission EOV End of Volume EP Emulation Program EPDE Electronic Product Data Exchange EPOW Emergency Power Off Warning EPROM Eraseable Programable Read Only Memory EPS Encapsulated PostScript EPSF Encapsulated PostScript Format ER Entity Relationship ERDS Error Recording Data Set EREP Environmental Record Editing and Printing program ES Errored Second ESA Extended Service Area ESC Escape ESCON Enterprise System Connection Architecture ESD Electronic Software Distribution ESD External Symbol Dictionary ESDI Enhanced Small Device Interface ESDS Entry Sequenced Data Set ESF Extended SuperFrame ESPRIT European Strategic Programme for Research and development in Information Technology ESQA Extended System Queue Area ETB End of Transmission Block ETCOM European Testing and Certification for Office and Manufacturing protocols ETS European Telecommunication Standard ETSI European Telecommunication Standards Institute ETX End of Text EUnet European Unix Network EUUG European Unix User Group EVI EVent Information EWOS European Workshop for Open Systems EXCP EXecute Channel Program EZ Excessive Zeros

F F/STP Foil STP FA Foreign Agent FAQ Frequently Asked Questions FAST Federation Against Software Theft FAT File Allocation Table FBA Fix Block Architecture FBA Fixed Blocked ANSI-defined printer control characters FBM Fix Block Modus FC File Control FCB Format Control Buffer FCP File Control Program FCS Frame-Check Sequence FCT File Control Table FDD Fixed Disk Drive FDDI Fiber Distributed Data Interface FEAL Fast Data Encipherment Algorithm FEP Front-End Processor FF Formfeed FH Frame Handler FIFO First In, First Out FIPS Federal Information Processing Standard FLOPS Floating-point operations per second FMLI Forms and Menu Language Interpreter FOB Form Overlay Buffer FOND Font family descriptor FORTRAN FORmula TRANslator FPU Floating Point Unit FRAD Frame Relay Access Device FROM Factory ROM FRU Field Replaceable Unit FS Field Separator FS File Separator FSB Front Side Bus FSF Free Software Foundation FSK Frequency Shift Keying FT Fault Tolerant FTAM File Transfer and Access Method FTP File Transfer Protocol

G GAL Global Address List GATF Graphic Arts Technical Foundation GB GigaByte (1,073,741,824 bytes) GCR Group Coded Recording GDG Generation Data Group GDS Global Directory Service GDT Global Descriptor Table GDTR Global Descriptor Table Register GE Graphic Escape GETVIS GET VIrtual Storage GID Group ID GIF Graphics Interchange Format GIS Generalized Information System GIX Global Internet Exchange GKS Graphical Kernel System GML Generalized Markup Language GOSIP Government OSI Profile GP General Protection GPIB General-Purpose Interface Bus GRS Global Resource Serialization GS Group Separator GTF Generalized Trace Facility GUI Graphical User Interface GUIP Graphical User Interface for Blind people GUUG German Unix User Group

H H&J Hyphenation and Justification HA Home Address HA Host Agent HADA High Availability Disk Array HCL Hue, Chroma, and Luminance HDLC High Level Data Link Communications HDSL High-bit rate Digital Subscriber Loop HDTV High Definition TV HE High End (system) HGC Hercules Graphics Card HIC Host Interface Computer HLL High Level Language HLS Hue-Lightness-Saturation HMD Head-Mounted Display HMMP HyperMedia Management Protocol HMMS HyperMedia Management Schema HPCL Hewlett-Packard Control Language HPFS High Performance File System HPGL Hewlett-Packard Graphical Language HPR High Performance Routing HR Horizontal Rule HSB Hue-saturation-brightness HSELAN High Speed ELAN HSI Hue-Saturation-Intensity HSLAN High Speed LAN HSSI High Speed Serial Interface HSV Hue-Saturation-Value HT Horizontal Tab HTML Hypertext Markup Language HTTP Hypertext Transfer Protocol Hz Hertz

I I-Net Intranet I/O Input/Output I/O Input/Output IA5 International Alphabet Five IAB Internet Activities Board IC Integrated Circuit ICEM Integrated Computer Engineering and Manufacturing ICMP Internet Control Message Protocol ID Identifier IDA Indirect Data Addressing IDA Intelligent Drive Array IDE Integrated Drive Electronics IDEA International Data Encryption Algorithm IDL Interfacce Definition Language IDT Interrupt Descriptor Table IEC InterExchange Carrier IEEE Institute of Electrical and Electronic Engineers IETF Internet Engineering Task Force IF Interrupt Flag IFF Interchange File Format IFIP International Federation of Information Processing IFS Interchange File Separator IFS InterFrame Space IGES Initial Graphics Exchange Specification IGMP Internet Group Membership Protocol IGS Interchange Group Separator II Interactive Interface IISP Interim Interswitch Signaling Protocol IKT Informatione- und Kommunikationstechnik ILC InterLanguage Communication IML Initial Microcode Load IMPL Initial Microprogram Load IMR Interrupt Mask Registers IMS Information Management System IMS/VS Information Management System / Virtual Storage INP Inhibit Presentation INT INTerrupt IOC ISDN Ordering Code IOCP Input/Output Configuration Program IOCS Input/Output Control System IOGEN Input/Output device GENeration IOPL Input/Output Privilege Level IOS Input/Output Supervisor IP Internet Protocol IPL Initial Program Load IPM InterPersonal Message IPSE Integrated Project Support Environment IPX Internet Packet Exchange IR Index Return IRC Internet Relay Chat IRDS Information Resource Dictionary System IRQ Interrupt ReQuest IRS Interchange Recors Separator IS Information System IS Intermediate System IS International Standard ISA Industry Standard Architecture ISAM Indexed Sequential Access Method ISDN Integrated Services Digital Network ISFMS Indexed Sequential File Management System ISMF Interactive Storage Management Facility ISO International Standardization Organisation ISO IEC ISO International Electrotechnical Commitee ISODE ISO Development Environment ISP Internet Service Provider ISPF Interactive System Produvtivity Facility ISPF/PDF ISPF Program Development Facility ISR Information Storage and Retrieval ISR Intermediate Session Routing ISSE Intel SIMD Sreaming Extension ISV Independent Software Vendor IT Indent Tab ITB Intermediate Transmission Block ITLD International Top-Level Domain ITRC Information Technology Requirements Council ITU International Comunication Union (ehem. CCITT) ITV Interactive TeleVision IUS Interchange Unit Separator IWS Intelligent WorkStation

J JCC Job Control Command JCL Job Control Language JCS Job Control Statement JCT JES Control Table JCT Journal Control Table JECL Job Entry Control Language JEIDA Japan Electronics Industry Development Association JES Job Entry Subsystem JPEG Joint Photographic Experts Group

K K Kilobyte KB KiloByte (1,024 Bytes) KBPS KiloBits Per Second kHz KiloHertz KIP Kinetics Internet Protocol KIPS Kilo Instructions per second KL Key Length KOPS Kilo Operations per second KSDS Key Sequenced Data Set KVA KiloVolt Ampere

L L2F Layer 2 Forwarding L2TP Layer 2 Tunneling Protocol LAN Local Area Network LAPS LAN Adapter Protocol Support Program LBL Label LCD Liquid Crystal Display LCS Lotus Communication Server LDAP Lightweight Directory Access Protocol LDMF Librarian Disc Master File LDS Linear Data Set LDT Local Descriptor Table LE Low End (system) LEC LAN Emulation Client LEC Local Exchange Carrier LED Light Emitting Diode LF Linefeed LIC Line Interface Computer LIFO Last In, First Out LILO Last In, Last Out LILO Linux Loader LIM-EMS Lotus Intel Microsoft EMS LIOCS Logical Input/Output Control System LISP List Programming LLC2 Logical Link Control Layer 2 LOC Lines Of Code LOS Local Operator System LPI Lines Per Inch LRC Longitudinal Redundancy Checking LRU Least Recently Used LSD Least Significant Digit LSI Large Scale Integration -> VLSI LU Logical Unit LUB Logical Unit Block LUT Look Up Table LVT Light Valve Technology LW Line Work LZ Lempel-Ziv LZW Lempel-Ziv-Welch

M MAC Media Access Control MAN Metropolitan Area Network MAP Maintenance Analysis Procedure MAP Manufacturing Automation Protocol MAPI Messaging Applications Programming Interface MB MegaByte (1,048,576 bytes) MBCS Multiple Byte Character Set MBONE Multicast Backbone MBPS MegaBits Per Second MCA Micro Channel Architecture MCBF Mean Cycles Between Failures MCCOI Multimedia Communications Community of Interest MCGA MultiColour Graphics Array MCI Media Control Interface MD Management Domain MD5 Message Digest 5 MDA Monochrome Display Adapter MEB Memory Expansion Board MFA Modify Field Attribute MFC Microsoft Foundation Classes MFKS Multifunktionales Konferenzsystem MFLOPS Million Floating-Point Operations Per Second MFM Modified Frequency Modulation MFV Multi File Volume MFWS MultiFunction WorkStation MGA Monochrome Graphic Adapter MH Mobile Host MHS Message Handling System MI Multiple Inheritance MIB Management Information Database MICR Magnetic Ink Character Reader MIDI Musical Instrument Digital Interface MIME Multipurpose Internet Mail Extensions MIPS Millions of Instructions Per Second MISC Minimum Instruction Set Computer -> CISC, RISC MLPPP MultiLink PPP MMDF Multi-Channel Memorandum Distribution Facility MMDS Multi-Megabit Data Services MMFS Manufacturing Manage Format Standard MMX Multi Media eXtensions MNP Microcom Network Protocol MODEM MOdulator/DEModulator MOPS Mega Operations per second MOTIS Message-Oriented Text Interchange Systems MP Multiprocessing MPC Multimedia PC MPEG Motion Picture Experts Group MPOA MultiProtocol Over Asynchronous transfer mode MPSD MultiPath Storage Director MPX multiplex MS Message Store MS-DOS Microsoft Disk Operating System MSA Metropolitan Statistical Area MSD Most Significant Digit MSG Message MSM MultiSession Monitor MSW Machine Status Word MTA Message Transfer Agent MTBF MeanTime Between Failures MTDA Mean Time Data Availability MTS Message Transfer System MUD Multi-User Dungeon MULTICS MULTiplexed Information and Computing Service MUMPS Massachusetts General Hospital Utility Multi-Programmings System MUMPS Multi-User Multi-ProgrammingSystem MVS Multiple Virtual System MVS/ESA Multiple Virtual System / Extended System Architecture MVS/XA Multiple Virtual System / Extended Architecture MVSCP MVS Configuration Program

N NAC Network Adapter Card NAK Negative Acknowledgement NAP Network Access Point NAS Network Access Server NAT Network Address Translation NAU Network Addressable Unit NBS National Bureau of Standards NBS Numeric BackSpace NC Numeric Control NCCF Network Communication Control Facility NCP Network Control Processor NCP Network Control Program NCP/VS Network Control Program/Virtual Storage NDIS Network Driver Interface Specification NetSP Network Security Program NFNT New font numbering table NFS Network File System NHRP Next Hop Routing Protocol NIC Network Interface Card NIC Network Information Center NIS Network Information Service NIST National Institute for Standards and Technology NJE Network Job Entry NL New Line NLQ Near Letter Quality NLT Nucleus Load Table NMI NonMaskable Interrupt NNTP Network News Transport Protocol NSA National Security Agency NSC1 Network Systems Cypher One NSP Numeric Space NSS NATURAL Security-System NT Network Termination NTS/2 Network Transport Services/2 NTSC National Television System Committee NUI Network User Identification NUL Null NUMA Non-Uniform Memory Access NVOD Near Video On Demand NVRAM NonVolatile Random Access Memory NVS NonVolatile Storage

O O/R Originator / Recipient OC3 155 Mbit/s OCR Optical Character Recognition OCX OLE Control Extension ODA Open Document Architecture ODSI Open Directory Service Interfaces OEM Original Equipment Manufacturer OI Object Interface OLE Object Linking and Embedding OLTEP On-Line Test Executive Program OLTP On-Line Transaction Processing OMG Object Management Group OMR Optical Mark Recognition OO Objektorientierung OOA Objektorientierte Analyse OODBMS Object Oriented DBMS OOP Objektorientierte Programmierung OOPL Object Oriented Programming Language OOPS Object Oriented Programming System OP Operator Panel OPI Open Prepress Interface ORB Object Request Broker OS Operating System OS/2 Operating System/2 OSA Office Systems Architecture OSA Open System Architecture OSF Open Software Foundation OSI Open Systems Interconnection OSI/RM OSI Reference Model OSNS Open Systems Network Support OSPF Open Shortest Path First OSTC Open System Testing Consortium OTPROM One Time Programable ROM OWL Object Windows Library

P PABX Private Automatic Branch Exchange PAD Packet Assembly Disassembly PAL Phase Alternating Line PAL Programmable Array Logic PAM Partitioned Access Method PAP Password Authentication Protocol PB PetaByte (1,125,899,906,842,624 bytes) PBX Private Branch Exchange PC Personal Computer PC Personal Computing PC Program Control PCB Printed Circuit Board PCB Program Control Block PCI Peripheral Component Interface PCI Program Controlled Interuption PCIL Private Core Image Library PCL Printer Control Language PCM Plug Compatible Manufacturers PCMCIA Personal Computer Memory Card International Association PCN Personal Communication Network PCP Program Control Program PCS Personal Communication Services PCT Private Communication Technology PCT Program Control Table PD Public Domain PDA Personal Digital Assistant PDAD Proposed Draft Addendum PDAU Physical Data Access Unit PDF Program Development Facility PDL Page Description Language PDO Portable Distributed Objects PDS Partitioned Data Set PDS Premise Distribution System PDS Processor Direct Slot PDU Protocol Data Unit PDX Printer Description Extension PE Printer's error PE Protection Enabled PEARL Processor and Experiment Automation Realtime Language PEM Privacy Enhanced Mail PEP Partitioned Emulation Program PER Program Event Recording PERL Practical Extraction and Report language PF Parity Flag PFK Program Function Key(board) PFM Printer Font Metric PGA Professional graphics adapter PGP Pretty Good Privacy PIB Program Information Block PID Process ID PIFS Point InterFrame Space PIM Personal Information Management PIN Personal Identification Number PIOCS Physical Input/Output Control System PL Procedure Library PL/1 Programming Language 1 PLI Programming Language 1 PLPA Pageable Link Pack Area PLT Program List Table PLU Primary Logical Unit PMMU Paged memory management unit PMS Pantone Matching System PMS Project Management System PMT Photomechanical Transfer (photostat) PMT Photomultiplier Tube PNNI Private Network-to-Network Interface POC Program-Operator Communication POP Point Of Presence POP Post Office Protocol POSIX Portable Operating System Interface for UNIX POTS Plain Old Telephone System POWER Priority Output Writer, Execution processors and input Readers PP Presentation Position PPD PostScript Printer Description PPGA Plastic Pin Grid Array PPM Pages Per Minute PPP Point-to-Point Protocol PPT Processing Program Table PPTP Point-to-Point Tunneling Protocol PPV Pay Per View PRDMD Private Directory Management Domain PRL Private Relocatable Library PRMD Private Management Domain PROM Programable Read Only Memory PSB Program Specification Block PSDN Packet Swiched Data Network PSRAM Pseudo SRAM PSSL Private Source Statement Library PSTN Public Swiched Telephone Network PSW Program Status Word PTF Program Temporary Fix PTR PoinTeR PU Physical Unit PUB Physical Unit Block PVC Permanent Virtual Circuit PVP Packet Video Processor PWB Printed Wire Board PWS Programmable WorkStation

Q QAM Quadrature Amplitude Modulation QBE Query By Example QCIF Quater Common Intermediate Format QIC Quarter-Inch Cartridge QSAM Queued Sequential Access Method QTAM Queued Teleprocessing Access Method

R R0 Record zero RACF Resource Access Control Facility RAID Redundant Array of Inexpensive Disks RAID Redundant Array of Independent Disks RAM Random Access Memory RARP Reverse Address Resolution Protocol RBA Relative Byte Adresse RC Robot Control RCP Remote Communication Processor RCS Revision Control System RDA Remote Data Access RDBMS Relational DataBase Management System RDN Relative Distinguished Name RES Restore RF Resume Flag RFC Request For Comments RFF Required Form Feed RFS Remote File System RGB Red, Green, Blue RGM Red, Green, Blue (Monitor) RIFF Resource Interchange File Format RIP Raster Image Processor RIP Router Information Protocol RISC Reduced Instruction Set Computer RJE Remote Job Entry RL Relocatable Library RLD Relocation Dictionary RLE Run Length Encoded file RLL Run Length Limited RMF Resource Management Facility RNL Required New Line ROM Read Only Memory RPC Remote Procedure Call RPG Report Program Generator RPL Requestor's Privilege Level RPL Research Programming Language RPM Revolutions Per Minute RPS Rotational Position Sensing RPT Repeat RRDS Relative Record Data Set RRED Right Reading Emulsion Down RREU Right Reading Emulsion Up RS Record Separator RSP Required Space RSVP Resource Reservation Protocol RTC Real Time Clock RTCP Realtime Transport Control Protocol RTF Rich Text Format RTM/SF Realtime Monitor / Systems Facility RTP Realtime Transport Protocol RTSE Reliable Transfer Service Element RWSI Remote Workstation Interface

S S.W.I.F.T. Society for Worldwide Interbank Financial Telecommunication S/STP Shielded STP SA Set Attribute SAA Storage Accounting Area SAA System Application Architecture SAM Sequential Access Method SAP Service Access Point SAP Service Advertising Protocol SAR Segmentation And Reassembly SBCS Single Byte Character Set SBS Subscript SC Storage Control SCA Shared Control Array SCCS Source Code Control System SCDS Source Control Data Set SCI Scalable Coherent Interconnect SCODL Scanned Conversion Object Description Language SCP Storage Control Program SCP System Control Program SCRAM Static Column Random Access Memory SCSI Small Computer Systems Interface SDH Synchronous Digital Hierarchy SDK Software Development Kit SDL System Directory List SDLC Synchronous Data Link Control SDRAM Synchronous DRAM SDSF System Display and Search Facility SE Software Entwicklung SE System Engineer SECC Single Edge Contact Connector SECAM Sequential Couleur a'Memorie SEL Select SEPP Single Edge Processor Package SET Software-Engineering-Technology SF Sign Flag SF Support Facility SFA Salesforce Automation SFBI Shared Frame Buffer Interconnect SFE Start Field Extended SFT System Fault Tolerance SFTP Shielded Foil Twisted Pair SGML Standard Generalized Markup Language SHTTP Secure HTTP SHY Syllable Hyphen SI Shift In SI Single Inheritance SI Standard Interface SIFS Short InterFrame Space SIFT Stanford Information Filtering Tool SIG Special Interest Group SIM Service Information Message SIMD Single Instruction Multiple Data SIMM Single In-line Memory Module SIRDS Single Image Random Dot Stereogram SIT System Initialization Table SL Source Statement Library SLD Structured Logic Design SLED Single Large Expensive Disk SLIP Serial Line Internet Protocol SLR Service Level Reporter SLU Secondary Logical Unit SM Set Mode SMDS Switched Multimegabit Data Service SMF System Management Facility SML MVS Storage Management Library SMLI Stateful MultiLayer Inspection SMP Symetric MultiProcessing SMP System Modification Program SMS Storage Management Subsystem SMTP Simple Mail Transfer Protocol SNA System Network Architecture SNADS SNA Distribution Services SNMP Simple Network Management Protocol SNOBOL String Oriented Symbolic Language SNT Sign-On Table SO Shift Out SOD Service On Demand SOH Start Of Heading SOM System Object Model SOS Start Of Significance SP Space SPA Software Publishers Association SPARC Scalar Processor ARChitecture SPDU Session Protocol Data Unit SPM System Performance Monitor/2 SPOOL Simultaneous Peripheral Operations On Line SPP Scalable Parallel Processing SPS Superscript SPX Sequenced Packet eXchange SQL Structured Query Language SQL/DS Structured Query Language / Data System SRAM Static Random Access Memory SRT System Recovery Table SRU Shared Resource Unit SS Single Sided SS Stack Segment SSCP System Service Control Point SSID SubSystem IDentifier SSL Secure Socket Layer STM Synchronous Transfer Mode STP Shielded Twisted Pair STT Secure Transaction Technology STX Start of Text SUB Substitute SV Storage Violation SVA Shared Virtual Area SVC Supervisor Call SVC Switched Virtual Circuit SVGA Super-VGA SW Switch SWOP Specifications for Web Offset Printing SYN Synchronous Idle SYSOP System Operator

T T1 1.544 Mbit/s T3 45 Mbit/s TARGA Truevision Advanced Raster Graphics Adapter TB TeraByte (1,099,511,627,776 bytes) TC Terminal Control TCA Task Control Area TCAM Telecommunications Access Method TCB Task Control Block TCL Tool Command Language TCM Thermal Conduction Module TCO Triple Capacity Option TCP Terminal Control Program TCP Transmission Control Protocol TCP/IP Transmission Control Protocol/Internet Protocol TCT Terminal Control Table TCTTE Terminal Control Table Terminal Entry TCU Transmission Control Unit TD Transient Data TDIA Transient Data Input Area TDM Time-Division Multiplexing TDOA Transient Data Output Area TDP Transient Data Program TEO Technical Electronic Office TF Trap Flag TIC Technical Integrity Check TIFF Tagged Image File Format TIOA Terminal Input/Output Area TLB Translation Lookaside Buffer TLBL Tape Label TMO Thermo-Magneto-Optic technology TNEF Transport-Neutral Encapsulation Format TOC Table Of Contents TOP Technical Office Protocol TPDU Transport Protocol Data Unit TPF Transaction Processing Facility TPI Tracks Per Inch TPM Third-Party Maintenance TPS Transactions Per Second TRN Transparent TS Telecommunication System TS Temporary Storage TSIOA Temporary Storage Input/Output Area TSO Time Sharing Option TSP Temporary Storage Program TSR Terminate and Stay Resident TTA Teletex Attachment (Teletexzusatz) TTL Transistor Transistor Logic TTR Track Record TTY TeleTYpe TWA Transaction Work Area TWA Two-Way Alternate TWS Two-Way Simultaneous TX Telex TXT Text

U UA User Agent UAE Unrecoverable Application error UART Universal Asynchronous Receiver/Transmitter UBR Undefined Bit Rate UBS Unit Backspace UCB Unit Control Block UCR Undercolor removal UCS Universal Character Set UCSB Universal Character Set Buffer UCW Unit Control Word UDP User Datagram Protocol UI User Interface UID User ID UMB Upper Memory Block UNC Universal Naming Convention UNC Universal Network Convention UPC Universal Product Code UPS Uninterruptible Power Supply UPSI User Program Switch Indicator UR Unit Record URL Uniform Resource Locator US Unit Separator USART Universal Synchronous/Asynchronous Receiver/Transmitter USENET USEr NETwork USM UnSharp Masking USRT Universal Synchronous Receiver/Transmitter USV Unterbrechungsfreie StromVersorgung UTP Unshielded Twisted Pair UUCP Unix-to-Unix Copy Program

V VAD Value Added Dealer VAN Value Added Network VAP Value Added Process VAR Value Added Reseller VAST Virtual Archive Storage Technology VB Visual Basic VBA Visual Basic for Applications VBR Variable Bit Rate VBN Vermitteltes Breitbandnetz VC Virtual Circuit VC-SDRAM Virtual Channel SDRAM VCC Virtual Circuit Connection VCI Virtual Circuit Identifier VCNA Vtam Communication Network Application VCPI Virtual Control Program Interface VDAC Video Digital Analog Converter VDI Video Display Interface VDT Video Display Terminal VDU Visual Display Unit VERONICA Very Easy Rodent-Oriented Netwide Index to Computerized Archives VGA Video Graphics Array VGC Video Graphics Controller VGM Video Graphics Monitor VHDSL Very High-bit rate Digital Subscriber Loop VHLL Very High-Level Language VHS Video Home System VIO Video Input/Output VIO Virtual Input/Output VIPA Virtual IP Addressing VLAN Virtual LAN VLSI Very Large Scale Integration VM Virtual Machine VM/SP Virtual Machine / System Product VMMAP VM Monitor Analysis Program VMOS Vertical MOS VMPPF VM Performance Planning Facility VMPRF VM Performance Reporting Facility VMS Virtual Management System VOD Video On Demand VPD Vital Product Data VPDN Virtual Private Data Network VPI Virtual Path Identifier VPN Virtual Private Network VR Virtual Reality VRAM Video RAM VRML Virtual Reality Modeling Language VRC Vertical Redundancy Checking VS Virtual Storage VSAM Virtual Storage Access Method VSAT Very Small Aperture Terminal VSM Virtual Storage Management VSN Volume Serial Number VT Vertical Tab VTAM Virtual Telecommunications Access Method VTOC Volume Table of Contents VTP Virtual Terminal Protocol VTP Virtual Terminal Program VTX VideoTeXt VVDS VSAM Volume Data Set

W W3 World Wide Web W4WG Windows for Workgroups WABI Windows Application Binary Interface WAIS Wide Area Information Service WAN Wide Area Network WATM Wireless ATM WATS Wide Area Telecommunications Service WHAT Wireless Hybrid Asynchronous Time-bounded WIMP Windows, Icons, Mice and Pointers WINS Windows Internet Name Service WMAC Wireless Media Access Control WMF Windows metafile WORM Write Once, Read Many times WOSA Windows Open Services/Systems Architecture WRED Wrong Reading Emulsion Down WREU Wrong Reading Emulsion Up WS WorkStation WTO Write To Operator WUS Word Underscore WWW World Wide Web WXTRN Weak External Reference WYSIWYG What You See Is What You Get

X XA EXtended Architecture XIP Execute In Place XLT Transaction List Table XMS Extended Memory Specification XT eXtended Technology

Y Y2K Year 2000 YIQ (color components in NTSC color space) YUV (color components in SECAM and PAL color spaces)

Z ZBR Zero Bug Release ZD Zero Defects ZF Zero Flag