Multimedia Terminology

A

AAC - Advanced Audio Coding

A compression method for audio signals, which allows better compression rates than MP3. See also: SDMI.

AFC - Automatic Frequency Control

A system to automatically find the best frequency.

AI - Artificial Intelligence

The abilitly of a machine to recognize and learn.

ALGOL - ALGOrithmic Language

A programming language.

ALU - Arithmetical-Logical Unit

The part of a CPU that does the actual calculations.

ANSI - American National Standards Institute

APU - Arithmetical Processor Unit

ASCII - American Standard Code for Information Interchange

This is the U.S. standard (ISO 646, ANSI_X3.4-1968) character set for 7-bit information interchange. The recommended name is US-ASCII. It is used in the FTP ascii-mode.

ASIC - Application Specific Integrated Circuit

An IC designed for a specific application.

B

BASIC - Beginner's All-purpose Symbolic Instruction Code

A programming language.

BMP - BitMaP

The uncompressed bitmap image format with up to 8 bits per color (256 colors) of MS-Windows. See also: GIF, HDF, IFF, JPEG, PBM, PCD, PGM, PNG, PNM, PPM, TIFF, XBM.

BPI - Bits Per Inch

A measure for data density.

BPS - Bits Per Second

A unit for data transfer rates.

C

CAD - Computer Aided Design

Designing 2D/3D objects with the support of a computer. See also CIM.

CAE - Computer Aided Engineering

Constructing and testing objects with the help of a computer. See also CIM.

CAM - Computer Aided Manufacturing

Manufacturing objects with the support a computer. See also CIM.

CAP - Computer Aided Publishing

Editing papers, books, etc. with the help of a computer. Newer systems are called DTP.

CAQ - Computer Aided Quality (assurance/management)

Quality management / quality assurance with the support a computer. See also CIM.

CC - Compact Cassette

Another name for MCs.

CD - Compact Disc

A digital optical mass storage, introduced in 1982. There are two different sizes, 12 cm and ("single") 8 cm in diameter. Based on this there are three main types for audio (CD-DA), data (CD-ROM) and video (CD-V). Recordable discs are called CD-R, re-writable discs are known as CD-RW. All CD formats could be replaced by DVDs in the near future.

The data format for compact discs is derived from the CD-DA format which is defined in the "Red Book". The other formats are defined in other "colored books" as follows (number of bytes in brackets):

The Red Book: Audio Sector
Audio Sample Bytes (2352)
The Yellow Book: Data Sector Mode 1
Sync (12)	Header (4)	User Data (2048)		EDC (4)	Zero (8)	ECC (276)
The Yellow Book: Data Sector Mode 2
Sync (12)	Header (4)	User Data (2336)
The Green Book: Data Sector Mode 2 - Form 1 (CD-ROM-XA Form 1)
Sync (12)	Header (4)	SubHeader (8)	User Data (2048)		EDC (4)	ECC (276)
The Green Book: Data Sector Mode 2 - Form 2 (CD-ROM-XA Form 2)
Sync (12)	Header (4)	SubHeader (8)	User Data (2324)			EDC (4)

Note: EDC and ECC are data blocks for error correction purposes.

CD32 - Compact Disc - 32 [bits]

This very first 32bit multimedia CD player was developed by Commodore (introduced in 1993) and is based on the Amiga 1200 personal computer. It supports the following formats: CD32, CDTV, CD-DA, CD+G and MPEG videos.

CD-Audio - Compact Disc - Audio

See below at: CD-DA

CD-DA - Compact Disc - Digital Audio

The standard 12 cm audio CD format offers up to 80 minutes of music. It was developed by Philips (1982) and is defined in the so-called "Red Book" for CDs. Very often this format is referred to as "CD".

A CD-DA contains stereo audio samples with 16 bit resolution which are sampled at 44.1 kHz (44,100 samples per second). This results in: 44,100 samples/s * 2 (stereo) * 2 bytes/sample (16 bit) = 176,400 bytes/s. One sector contains samples for 1/75 s (2352 bytes).

There are also special formats: CD+G, CD+MIDI. Maxi-CDs are sometimes marked "CD-MS".

CD-EBG - Compact Disc - Electronic Book G?

This CD-ROM format was designed by Sony (1992). It is based on the 8 cm CD size. The player is of the walkman type. (Short: a flop!)

CD+G - Compact Disc + Graphics

This is a combination of a normal CD-DA with additional graphics information.

CD-I - Compact Disc - Interactive

A CD-ROM format designed by Philips (1992), defined in the "Green Book" for CDs. Philips CD-I multimedia players support CD-DA, CD+G and CD-I discs. (Short: a flop!)

CD+MIDI - Compact Disc + MIDI

This is a combination of a normal CD-DA with additional MIDI data.

CD-MS - Compact Disc - Maxi Single

Another name for Maxi-CD.

CDP - Compact Disc Player

A device that is capable of playing CDs.

CDR - Compact Disc Recorder

A device that is capable of recording on CD-Rs. Most modern devices also work as a CDP.

CD-R - Compact Disc - Recordable

A CD which can be recorded on only once using a CDR. Therefore this is also known as CD-WO or CD-WORM. The format and the properties are defined in the "Orange Book". There are discs with 560 and 660 MB capacity. These discs are mostly colored golden to not confuse them with the normal silver CDs. See also: CD-RW.

CD-ROM - Compact Disc - Read Only Memory

The CD-ROM was introduced in 1985. It is a single-sided, single-layered CD containing up to 650 MByte of data. Most discs are based on the standard file system ISO-9660, developed by Sony & Philips (?).

There are several special formats: CD-EBG, CD-I, CDTV, CD32, PhotoCD...

Since all compact disc drives are based on the CD-DA player, a single-speed CD-ROM drive transfers 150 kB/s (75 sectors/s * 2048 bytes/sector), double-speed means 300 kB/s (the discs rotate at the double speed), quadruple-speed means 600 kB/s and so on. The maximum speed is about 48x.

CD-ROM-XA - Compact Disc - Read Only Memory - eXtended Architecture

A certain format for CD-ROMs, defined in the "Yellow Book" for CDs.

CD-RW - Compact Disc - ReWritable

This is kind of a "CD-RAM" since it is a mass memory similar to a CD-ROM, but can be deleted and rewritten again. Like the CD-ROM and the CD-R it was developed for computer data, but can also be used as a re-writable CD-DA. However, most audio CDPs are not capable of playing them.

CDTV - Commodore Dynamic Total Vision

This first ever multimedia CD player was developed by Commodore (1991) and is based on the Amiga 500 personal computer. The CDTV player supports CDTV, CD-DA, CD+G, CD+MIDI. (Short: a flop!)

CD-V - Compact Disc - Video

An early, analogous format for video on CDs (1980s). Also known as LD. See also: DVD.

CD-WO - Compact Disc - Write Once

A shorter name for CD-WORM.

CD-WORM - Compact Disc - Write Once Read only Memory

A CD-like disc that can be written once and after this works just like a "normal" CD. The more common name for these discs is CD-R. A shorter name is also CD-WO.

CGI - Common Gateway Interface

The quasi-standardized interface between a HTTP server and the local programs it executes.

CIM - Computer Integrated Manufacturing

Manufacturing objects with computers. This integrates the use of computers within several steps like CAD, CAE, CAM and CAQ.

CISC - Complex Instruction Set Computer

A CPU that knows more than 100 instructions. See also: RISC.

COBOL - COmmon Business Oriented Language

A programming language.

CPI - Characters Per Inch

A unit for printer font width.

CPS - Characters Per Second

A unit describing data transfer speed, for example of a printer.

CPU - Central Processing Unit

The "heart" of a computer. Sometimes called MPU.

D

DAT - Digital Audio Tape

This digital recordable tape format was developed by Sony. It was introduced in Japan in 1987 and in Europe in 1992. Because of the high costs it was not widely spread in the music field, but used by professionals. It also had minor meaning as a backup medium for computer data. See also CD-ROM, DCC, MD.

DCC - Digital Compact Cassette

A digital recordable tape format designed by Philips (1992). DCC tapedecks allow to replay standard MCs. A digital recording on a DCC can only be copied in analogous mode. See also DAT, MD.

DMA (1) - Direct Memory Access

Accessing the main memory of a computer by co-processors without interrupting the main CPU.

DMA (2) - Dietmar's Multimedia Acronyms

Your guide through the rainforest of cryptical abbreviations.

DOS - Disc Operating System

The part of the OS that controlles the hard- and floppy disc drives.

DPI - Dots Per Inch

A measure of the density of scanner input or printer output.

DSP - Digital Signal Processor

An IC specially designed for digital processing of high data flux at high rates, for example for video images and sounds, without loading the CPU.

DTD - Document Type Definition

These files are written in SGML. They describe the syntax of markup languages and can be used by SGML syntax parsers.

DTP - DeskTop Publishing

Editing books, papers etc. on a (desktop) computer. See also: CAP, DTV.

DTS - Digital Theater System

This digital method of encoding multi-channel sound is used in motion picture theaters and can also be used on CD-DAs and DVD-Video discs.

For DVD, there are at least two formats commonly in use:

· DTS 5.1 (6 channels: front left/center/right, surround left/right and one LFE channel) and

· DTS-ES (see there).

Both formats contain sound in 20 bit resolution per channel.

DTS-ES - Digital Theater System - Extended Surround

A digital method to encode surround sound channels. There are two different formats, both are compatible extensions of DTS 5.1.:

· The DTS-ES 6.1 discrete format has 7 discrete channels (front left/center/right, surround left/center/right and one LFE channel) while

· the DTS-ES 6.1 matrix format has only 5.1 discrete channels plus a 6th surround center channel matrixed (encoded) in the two rear channels (surround left/right).

DTV - DeskTop Video

Editing videos on a (desktop) computer. See also: DTP.

DVD - Digital Versatile Disc (earlier name: Digital Video Disc)

A mass storage, mainly designed to replace all other formats of video storage like VHS tapes and LD/CD-V. The DVD standard was set up in December 1995 by a consortium of the most important motion picture producers and Hi-Fi electronics manufacturers. In Europe, it was introduced in 1998.

A DVD contains up to 17 GB of data on one or two sides with one or two layers per side. The DVD-Video format allows several options like up to eight different languages, multi-channel surround sound, and sub-titles in up to 32 different languages. Most DVD-Players can play some kinds of CDs, since the priciple of this medium is based on the CD one.

DVDs could become a full replacement for the CD type of media. The advantage that all DVD types have in common is the much higher data capacity. The DVD-Audio therefore offers higher quality than the CD-DA and also the option of multi-channel surround sound. There possibly will also be DVD-ROM, DVD-R and DVD-RW as replacements for CD-ROM, CD-R and CD-RW, respectively.

See also: HDCD, SACD, MPEG.

E

E-Mail - Electronic Mail

Electronic mail can be transferred with several protocols like POP and SMTP.

EP - Extended-Playing (record)

This term applies to a CD-DA with only a few titles on it. (See also: LP.)

ESC/P - Epson Standard Code for Printers

F

FD - Floppy Disk

A mass storage medium based on flexible ("floppy") disks with magnetic surfaces. The oldest disks are 8 inches in diameter, mini floppy disks are 5.25 inches in diameter and the modern MFDs are 3.5 inches in diameter. The first disks were only single-sided, but all modern FDDs use two magnetic read/write, one for each side.

FDD - Floppy Disk Drive

This mass storage system reads/writes binary data from/to FDs.

FIFO - First In - First Out

A principle for caches (fast intermediate storages). The data that were saved first, will be put out first. A FIFO memory is very often called "heap". See also LIFO.

FLOPS - FLoating point Operations Per Second

A measure for the power of computers.

FORTRAN - FORmula TRANslator

A programming language.

FPU - Floating point Processing Unit

The IC that handles floating point calculations. Modern CPUs have a built-in FPU.

FTP - File Transfer Protocol

G

G3 - Group 3

A digital fax standard (used in the ISDN).

GB - GigaByte

1 GB = 1024 MB = 1048576 KB = 1073741824 bytes. See also: TB.

GIF - Graphics Interchange Format

A bitmap image format with loss-free compression and transparent images with up to 8 bits per color (256 colors). The most used format in the WWW. See also: BMP, HDF, IFF, JPEG, PBM, PCD, PGM, PNG, PNM, PPM, TIFF, XBM.

GMT - Greenwich Mean Time

HD - Hard Disk

A fixed (i.e. non-removable) mass storage medium with one or more disks and one or two read/write heads per disk. See also: FD.

HDCD - High Definition Compact Disc

A newer kind of CD-DA with higher sound quality. However, they can only be played on special CDPs and DVD players. See also: DVD, SACD.

HDF - Hierarchical Data Format

This file format for texts, tables, floating point data, bitmap images and color maps was developed at the NCSA. See also: BMP, GIF, IFF, JPEG, PBM, PCD, PGM, PNG, PNM, PPM, TIFF, XBM.

HFS - Hierarchical File System

This MacIntosh file system is used on some CD-ROMs for the Macintosh computer system.

Hi-Fi - High - Fidelity

HTML - HyperText Markup Language

This SGML application is the hypertext format of the documents in the WWW. The current standard is HTML 2.0 (written down in RFC 1866). The most important feature is the possibility to link documents using URIs.

HTTP - HyperText Transfer Protocol

This Internet protocol was designed for the WWW. There are different versions:

· HTTP 0.9 (1989) - only for HTML files.

· HTTP 1.0 (1990) - for all file formats.

· Basic HTTP (July 1993) - first Internet draft - no RFC!

· HTTP/1.0 (September 1995) - "Best Current Practice" - the minimum standard in the third Internet draft - no RFC!

· HTTP/1.1 (Plan: April 1996): Shall become the HTTP 1.0 - RFC.

· HTTP/NG (Plan: December 1996) - incompatible binary format - more efficient!

I

IANA - Internet Assigned Numbers Authority

All world-wide unique parameter values for Internet protocols are registered with the IANA. The following character sets are officially registered:

US-ASCII, ISO-8859-1 .. ISO-8859-9, ISO-2022-JP, ISO-2022-JP-2, ISO-2022-KR, UNICODE-1-1, UNICODE-1-1-UTF-7, UNICODE-1-1-UTF-8.

IC - Integrated Circuit

An electronic circuit on a single silicon chip. Invented in 1957. Another name for IC is "chip".

ICANN - Internet Corporation for Assigned Names and Numbers

This non-profit company is now responsible for the administration of IP numbers, domain names and IPs. Therefore, it has three sub-organisations, one for each area of work.

The directing board consists of 19 members: 1 president, 9 delegated members (3 delegated by each of the three sub-organisations) and 9 elected members. The president is elected by the 18 members of the board.

In 2000, 5 of 9 to-be-elected members have been elected in a public online election.

ICMP - Internet Control Message Protocol

IETF - Internet Engineering Task Force

An open international organization, responsible for the development of the Internet, publicates RFCs.

IFF - Interchange File Format

A modular file format for bitmap images, text documents, samples, ... See also: BMP, GIF, HDF, JPEG, PBM, PCD, PGM, PNG, PNM, PPM, TIFF, XBM.

IP - Internet Protocol

see TCP/IP

IPA - International Phonetic Association

This organization has defined the phonetic symbols used in most dictionaries.

IRC - Internet Relay Chat

This service allows several people to exchange text information simultaneously.

ISBN - International Standard Book Number

ISDN - Integrated Services Digital Network

Standards (for example Euro-ISDN) for digital networks that allow digital phone, fax, video and data transfer using one single line with transfer rates of (Euro-ISDN) 19200, 38400, 57500, 64000 and (EEH-ISDN) 76000 bps. Some protocols are, for example V.110, V.120, X.75 and T70NL (used by T-Online, the online service of Deutsche Telekom AG).

ISO - International Organization for Standardization (not really an acronym!)

All standards of the ISO begin with ISO:

· ISO 646:1983 - "ASCII" standard 7-bit character set.

· ISO 8859-1 - "Latin-1" standard 8-bit character set. The first 128 characters are also known as "ASCII". This set includes most european special characters. It is used in operating systems like AmigaOS & X-Windows and in Internet services like E-Mail & WWW.

· ISO 8879:1986 - SGML applications

· ISO 9660:1991/1992? - CD-ROM file system.

ISP - Internet Service Provider

A company or an organization that offers Internet access.

J

JPEG - Joint Photograph Experts Group

A bitmap image format with efficient compression and 24 bits per color (16777216 colors). It was especially designed to compress photographs and photorealistic images and named after the group that set this standard. See also: BMP, GIF, HDF, IFF, PBM, PCD, PGM, PNG, PNM, PPM, TIFF, XBM.

K

KB - KiloByte

1 KB = 1024 bytes. See also: GB, MB, TB.

L

LAN - Local Area Network

A computer network limited to a certain local area, for example, a building, a floor of a higher building or some other limited space. See also WAN.

LCD - Liquid Crystal Display

A screen composed of several layers. One layer is between two electrodes. If an electrical field is applied to this layer, it becomes polarized and the incoming light can no longer be reflected and beam through all layers. Therefore the polarized area appears black.

LD - Laser Disc

Another name for CD-V. Diameter about 25 cm. See also: DVD.

LFE - Low Frequency Effect

Multi-channel sound formats like DTS use one ore more channels for effect sounds at low frequencies. Typical examples for LFE sound are thunder and explosions. When describing the sound format, the LFE channels are represented by the number behind the dot, for example "5.1" means 5 surround channels and one LFE channel. This is because LFE channels have only about one tenth of the bandwidth of the other channels.

LIFO - Last In - First Out

A principle for caches (fast intermediate memories). The data that were saved last, will be put out first. A LIFO memory is very often called "stack". See also FIFO.

LIMDOW - Laser Intensity Modulation Direct OverWrite

This is a newer method of a MOD for discs with 4 different magnetical layers. The main advantage of this method is that the information can be written in one single run. A 3.5" MOD by Fujitsu has a capacity of 640 MB.

LP - Long Player / Long-Playing (record)

A mechanical analogous replaying system, based on vinyl discs, developed in the 1950s (?). Mono and stereo samples are possible. The disk is read by a saphire needle. There are two formats (LP @ 33 rpm and maxi-single @ 45 rpm). Early versions rotated at 78 rpm. Singles have a smaller diameter.

LPI - Lines Per Inch

A measure for the density of a printer output.

M

Maxi-CD - Maxi - Compact Disc

A normal CD-DA with (mostly) several versions of one, two or more music titles. This is sometimes also referred to as CD-MS.

MB - MegaByte

1 MB = 1024 KB = 1048576 bytes. See also: GB, TB.

MC - (1) MusiCassette

A analogous, recordable magnetic tape format, developed by Philips (1972/1968?), also known as "CC". The tapes are characterized by their playing times: C-60/90/100/120 stands for 60/90/100/120 minutes, respectively.

MC - (2) Micro Cassette(TM)

This cassette format is smaller than the MusiCassette. One tape lenght is MC-60 = 60 minutes.

MD - Mini Disc

This digital recordable MOD format was developed by Sony (1992 in Europe shortly after the DCC). The compression of sound data allows up to 74 minutes of music. One can only copy an MD once to another MD. However, the MD has only limited success, especially with portable players, car-players and car-10x-changers. See also DAT.

MFD - Micro Floppy Disk

The modern 3.5 inch FD format.

MIDI - Musical Instruments Digital Interface

A standard interface for data exchange from, to and between musical instruments and computers.

MIME - Multipurpose Internet Mail Extensions

This Internet standard for transmissions of texts, sounds, images, videos, programs etc. is used in the Internet E-Mail service and in the HTTP.

MIPS - Million Instructions Per Second

A measure for the power of computers.

MMU - Memory Management Unit

The part of a computer that allows virtual memory (the simulation of main memory on a mass memory medium).

MOD - Magneto-Optical Disc

A digital, recordable mass memory system. A newer method is called LIMDOW. See also MD.

MODEM - MOdulator/DEModulator

A MODEM is an adaptor that connects a digital machine (PC) with an analogous (telephone) net. The most transfer protocols are named like V.n.

MP3 - MPEG-1 audio layer 3

This format for compressed audio data is widely spread via internet. Special portable MP3 players allow to download data from a computer and replay them autonomously. See also AAC, SDMI.

MPEG - Motion Picture Experts Group

Members of the group are (or have been) Commodore (CD32), Philips (CD-I), Matsushita ("Panasonic", "Technics"), Sony, JVC and Paramout Home Video. This group was founded to develop the MPEG standard (1993) for digital video, used, for example, on CD-ROMs. This standard allows up to 74 minutes of video, music and graphics. The audio compression method MPEG-1 Audio Layer 3, better known as MP3 is widespread via Internet. The compression method MPEG-2 is used on DVD-Video.

MPU - Micro Processor Unit

Another name for CPU.

N

NAT - Network Address Translation

NC - Network Computer

A computer that has only minimum hardware and uses software from the net it is connected to just when it is required. Because it is not necessary to install big software packages, it doesn't need any mass memory system like HDs.

NCSA - National Center for Supercomputing Applications

This center of the University of Illinois was the birth place of the first graphical WWW client named "Mosaic".

NFS - Net File System

A standardized file system that can be used by most OSs (by some only with additional software). This file system allows, for example, to use remote HDs like they were local to the user's machine.

NIDS - Network Intrusion Detection System

NNTP - Network News Transport Protocol

The Internet protocol for news transfer between UseNet servers. UseNet news transfers are mainly done via Internet.

NS-Diagram - Nassi-Schneidermann-Diagram

NT - Network Terminator

The end of an ISDN line. The user plugs his telephones, modems etc. in the NT box called NTBA.

NTP - Network Time Protocol

NTBA - Network Terminator B? A?

(see NT)

O

OEM - Original Equipment Manufacturer

A company that manufactures for other manufacturers.

OS - Operating System

The system software that controls all input/output - units and the applications.

OSA - Open System Architecture

P

PBM - Portable BitMap

A bitmap image format with 1 bit per color (black & white). This is one of the formats of the PBMplus graphics converter tools package. The other formats are PGM and PPM. See also: BMP, GIF, HDF, IFF, JPEG, PCD, PNG, PNM, TIFF, XBM.

PC - Personal Computer

A computer for personal use of one or a limited number of users.

PCD - Photographs on CD

The format of photographs on a PhotoCD. It is a bitmap format with up to 24 bits per color (16777216 colors). See also: BMP, GIF, HDF, IFF, JPEG, PBM, PGM, PNG, PNM, PPM, TIFF, XBM.

PCI - Programming Communications Interface

A European standard for plug-in-cards and communications software for PCs.

PCMCIA - Personal Computer Memory Card Interface Adaptor

This interface standard was developed for PCs, especially laptops. The plug to put in this interface has about the size of a credit card and was mostly intended for memory extensions, but nowadays there are "cards" for other purposes like SCSI hosts, network adaptors or modems.

PGA - Pin Grid Array

A type of IC cover design.

PGM - Portable GrayMap

A bitmap image format with up to 8 bits per color (256 grayscales). This is one of the formats of the PBMplus graphics converter tools package. The other formats are PBM and PPM. See also: BMP, GIF, HDF, IFF, JPEG, PCD, PNG, PNM, TIFF, XBM.

PhotoCD - Photograph Compact Disc

This CD-ROM format for photographs in PCD format was developed by Philips & Kodak (1992).

PNG - Portable Network Graphics

A bitmap image format with alpha channel, loss-free compression and up to 24 bits per color (16777216 colors). This "free" format was designed to replace GIF. See also: BMP, HDF, IFF, JPEG, PBM, PCD, PGM, PNM, PPM, TIFF, XBM.

PNM - Portable aNyMap

A part of the PBMplus graphics converter package can use any of the formats PBM, PGM and PPM. Those tools have PNM in the filename.

POP - Post Office Protocol

A protocol for E-Mail transfers from an ISP.

PPM - Portable PixMap

A bitmap image format with up to 24 bits per color (16777216 colors). This is one of the formats of the PBMplus graphics converter tools package. The other formats are PBM and PGM. See also: BMP, GIF, HDF, IFF, JPEG, PCD, PNG, PNM, TIFF, XBM

PPP - Point to Point Protocol

A common transfer protocol for serial connections to the Internet, based on TCP/IP. This replaces the former SLIP.

PPPoE - Point to Point Protocol over Ethernet

A variant of PPP via an Ethernet connection.

PSU - Power Supply Unit

R

RAM - Random Access Memory

The part of a computer memory where data can be read and written.

RFC - Request For Comments

This is the name for Internet standards. Examples are:

· RFC-1123 - Date stamp standard of the Internet

· RFC-1866 - HTML 2.0 (02 Nov 1995)

· RFC-1867 - FORM-based File Upload (06 Nov 1995)

RGB - Red Green Blue

The method of additive color mixing. Every color can be composed of three portions of red, green and blue light by adjusting brightness for each portion.

RISC - Reduced Instruction Set Computer

A CPU that knows (not many more) than 100 instructions. (See also: CISC.)

ROM - Read Only Memory

Computer memory or mass medium from which data can only be read.

S

SACD - Super Audio Compact Disc

This new sound memory was developed by Philips and Sony (1999) and delivers higher frequencies and more dynamics than the standard CD-DA. See also: DVD, HDCD.

SCSI - Small Computer System Interface

A system interface standard for input/output devices like harddrives, CD-ROM drives, CDRs, scanners, modems, etc.

SDMI - Secure Digital Music Initiative

An initiative, forced by the music industry, to replace MP3 as the standard format for commercial music productions. It includes a copy protection system. See also AAC.

SGML - Standard Generalized Markup Language

This language was designed by Dr. Charles F. Goldfarb to describe markup languages (so-called SGML applications). The description is called DTD.
SGML is defined in the standard ISO 8879.

SLIP - Serial Line Internet Protocol

A transfer protocol for serial connections to the Internet, based on TCP/IP. Meanwhile, this protocol is mostly replaced by PPP.

SMD - Surface-Mounted Device

A type of IC cover design.

SMPTE - Society of Motion Picture and Television Engineers

The SMPTE timecode is used on many video- and audio-tapes to syncronize digital cutting machines.

SMTP - Simple Mail Transfer Protocol

A protocol for E-Mail transfers to an ISP.

SSA - Super Smooth Animation

A file format for animation files which uses interlaced images to smoothen the animation.

T

TB - TeraByte

1 TB = 1024 GB = 1048576 MB = 1073741824 KB = 1099511627776 bytes.

TCP/IP - Transmission Control Protocol / Internet Protocol

The protocol on which all Internet transfers via HTTP, FTP, NNTP etc. are based on.

TIFF - Tagged Image File Format

A bitmap image format with up to 24 bits per color (16777216 colors) and 8 bit alpha channel (256 levels) = 32 bits per pixel. See also: BMP, GIF, HDF, IFF, JPEG, PBM, PCD, PGM, PNG, PNM, PPM, XBM.

TPI - Tracks Per Inch

A measure for the density of track-oriented mass memory media.

TV - TeleVision

U

UDP - Unified Datagram Protocol

URI - Uniform Resource Identifier

URIs are used to address resources in the Internet. They are devided in two different systems, URL and URN. HTML uses URIs to link hypertext documents to other resources.

URL - Uniform Resource Locator

URL is a URI format used to address resources in the Internet. The format is:
protocol://server:port/path/filename

URN - Uniform Resource Name

This URI format will make it possible to locate *any* resource (text, image, sound...) in the Internet by a *unique* name. The idea is to get the file no matter on which server it is located.
Currently this format is just an idea without a specific definition.

US-ASCII - United States ASCII

This is the recommended name for ASCII.

V

VCR - Video Cassette Recorder

VDU - Visual Display Unit

VHS - Video Home System

The leading standard for analogous video tapes. Other standards are, for example, Video2000 and Beta. VHS cassettes are marked E-180/240/300 etc. for tapes that are 180/240/300 minutes long, respectively.

VHS-C - Video Home System - Compact

A smaller analogous video standard, based on VHS. VHS-C cassettes are marked, for example EC-30 for a 30 minutes long tape.

VRML - Virtual Reality Modelling Language

Description language for 3-dimensional scenes. This is a 3d-hyperformat to click through virtual worlds. Will be used in the WWW.

VTR - Video Tape Recorder

V.n - (transfer protocols)

There are numerous different transfer protocols named V.n (transfer rates in bps):

· V.21

· V.22

· V.22bis (2400 bps)

· V.23 (1200 bps)

· V.24 - interface standard for data transfer of, for example, fax-machines, fax-printers and PCs