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There are 652 names in this directory beginning with the letter S.
S-MIME

(Secure MIME). A public-key encryption protocol for MIME (Multipurpose Internet Mail Extensions) attachments to electronic mail messages.

S-Video

Short for Super Video. A high-quality method of transmitting video signals over cable to a television from a device such as a Camcorder VCR or game machine. S-Video separates information into two signals: Chrominance (separates color information) and Luminance (brightness). This prevents color bleeding and dot crawl, and increases clarity and sharpness. Once the information is finally delivered to the TV it is done so as a single signal over one wire. S-Video requires an S-Video input jack on the television receiving video information, support for S-Video output on the device sending signals, and a special S-Video cable.

S/N ratio

Signal-to-Noise Ratio. The amount of communication signal in relation to the amount of interference, or noise, on the medium. It is usually expressed in decibels.

s/w

Software; the programs that tell a computer what to do. Hardware is the physical part of a computer system; the machinery and equipment.

SAA

Systems Application Architecture. A set of interfaces, guidelines, and protocols developed by IBM to encourage the development of software that is consistent regardless of hardware or operating system. SAA governs user interfaces, communications protocols, programming languages, and procedure libraries.

SAD

Systems Analysis Definition. The beginning step of systems analysis, in which the end user's requirements are defined in order to get an idea of what kind of system must be designed to meet those needs.

safety-critical system

A system in which safety is critical; a computer or other system which may cause deaths if it fails. An example would be the system that controls an airplane or a network of trains. These systems must be designed to exact specifications, and with extra components in case a component fails.

sag

A temporary drop in voltage; it may cause a problem in the computer.

SAGE

Systems Administrators Guild. A special technical group of the USENIX Association, a body which focuses on research and innovation in UNIX and open systems.

SAM

Symantec AntiVirus for Macintosh. An antivirus program from Symantec Corporation, Cupertino, California.

sampling

Taking the value of a signal at evenly spaced moments in time. This is the first of three steps in converting an analog signal into a digital one. After sampling, the signals must be quantized, then encoded.

sampling rate

Sampling (taking the value of a signal at evenly spaced moments in time) is one of the steps in converting an analog signal to a digital signal. The sampling rate is the frequency at which samples are taken. The sampling rate has to be twice the rate of the analog frequency that is captured, or more; the higher the sampling rate, the better quality signal.

samurai

A hacker who does legal cracking, for pay.


San Francisco Project

An IBM project to create a common foundation for developers through object technology-based business applications and Java.

sanity check

A review of a program's code to make sure there are no minor errors (such as entering the wrong character, forgetting to close parentheses, etc.) before checking the more complex logic aspects of the program.

sans serif

Without serifs, which are the short lines at the tops and bottoms of each stroke in a letter. (Sans means without in French). Sans serif typefaces are very simple; all caps sans serif lettering is called block lettering. Some examples of sans serif fonts are Helvetica, Avant Garde, and Oracle. Sans serif type is often used for headlines, signs, and ads.

Santa Cruz Operation

(SCO). A worldwide company based in Santa Cruz, California that specializes in UNIX operating systems. Some of its products are XENIX, Open Server, and Open Desktop.

SAPI

1. Scheduling Application Programming Interface. An application programming interface for business scheduling software such as Microsoft Schedule+. 2. Speech Application Programming Interface. An application programming interface from Microsoft that enables speech synthesis and speech recognition programs to communicate with the Windows 95 operating system.

sat

A nickname for satellite.

SATA

Serial ATA. Opposed to parallel ATA. Used in Storage.

SATA

Serial ATA. Opposed to parallel ATA. Used in Storage.

SATAN

Security Administrator Tool for Analyzing Networks. A freeware utility written by Dan Farmer and Wietse Venema that can be used to check a system for security vulnerabilities via the Internet.

satellite channel

A carrier frequency employed for satellite communications.

satellite link

A communications signal that goes from the earth to a satellite and back to earth.

save

To store a file on a disk or other storage medium. When a file is being edited, the changes are only in temporary memory (RAM), and will be lost when the power is shut off. To keep the changes in permanent memory, the file must be saved. It is a good idea to save often when working on a file, because if there is a power failure or the computer has to be restarted, all data not saved will be lost.

Save As

A command used to make a copy of a file, giving the copy a different name. The command “Save As” can be selected from the File menu.

Savvy Search

An experimental search system (http://guaraldi.cs.colostate.edu:2000/form) designed to query multiple Internet search engines simultaneously. Savvy Search provides multiple language versions of its search pages in at least sixteen languages.

SBC

Single Board Computer

Sbus

A bus developed by Sun Microsystems, now an IEEE (Institute of Electrical and Electronics Engineers) standard.

SC connector

A type of connector for fiber-optic cable that uses a plug and socket with a push-pull latch and has been used with FDDI, Fiber Channel and B/ISDN.

SCADA

SCADA (supervisory control and data acquisition) is a software program that gathers real time information for process control of equipment. SCADA can be used in industries such as telecommunications, oil and gas refining, water and waste control and transportation. The SCADA system gathers information, for example, about the location of a leak as well as determining how critical it is. The system will also organize and process the information, displaying it for users.

scalability

Ability to easily change in size or configuration to suit changing conditions. For example, a company that plans to set up a client/server network may want to have a system that not only works with the number of people who will immediately use the system, but the number who may be using it in one year, five years, or ten years.

scalable

Able to be changed in size or configuration to suit changing conditions. For example, a company that plans to set up a client/server network may want to have a system that not only works with the number of people who will immediately use the system, but the number who may be using it in one year, five years, or ten years.

scalable font

A font that can be used to print characters of any size. In a scalable font, the outlines of the characters are stored as vector graphics, rather than having a bitmap of each character. Because the outline can be scaled to any size and then filled in with dots, all sizes will print with the same quality. Examples of scalable fonts are the Adobe Type 1 PostScript fonts, TrueType fonts, Intellifont typefaces, and Speedo fonts.

Scalable Processor Architecture

(SPARC®). A high-speed RISC microprocessor developed by Sun Microsystems. It is used in Sun workstations, and has been adopted by some other computer manufacturers.

"SPARC® is a registered trademark of SPARC International, Inc. in the U.S. and other countries."


scalar

A single number, value, or data item, as opposed to a vector, matrix, or array (which contain multiple values).

ScanJet

A family of desktop scanners from Hewlett Packard, available in black and white or color models.

scanner

An input device that reads images or text and converts the data into digital signals. Graphical scanners read photos or other images into the computer and digitize them, producing bitmapped graphics files. Text scanners use optical character recognition software to read pages of text and produce editable text files. Bar code scanners, as used in stores, convert bar codes into digital information. Some types of scanners are flatbed scanners, sheet-fed scanners, hand-held scanners, and slide scanners.

scanners

There are many kinds of scanners. Graphical scanners read photos or other images into the computer and digitize them, producing bitmapped graphics files. Text scanners use optical character recognition software to read pages of text and produce editable text files. Bar code scanners, as used in stores, convert bar codes into digital information. See also flatbed scanner, sheet-fed scanner, hand-held scanner, and slide scanner.

scanno

A scanning error (as a typo is a typing error), caused by a glitch or minor malfunction in the scanner.

Scheduling API

Scheduling Application Programming Interface (SAPI). An application programming interface for business scheduling software such as Microsoft Schedule+.

Scholes, Christopher Latham

Designer, in 1872, of the QWERTY keyboard layout.

sci

Top-level newsgroup category for a newsgroup with hard-science discussions.

SCO

Santa Cruz Operation. A worldwide company based in Santa Cruz, California that specializes in UNIX operating systems. Some of its products are XENIX, Open Server, and Open Desktop.

Scorpion

A graphics and digital video encoder chip which makes adds Internet browsing and other interactive features to a television set. The Scorpion, also called the MC92100 chip, can be used with existing sets or new products. It can be used with set-top boxes and DVDs. Users will be able to display multiple windows on the screen, watching television and browsing the Internet at the same time.

SCP-DOS

Seattle Computer Products – Disk Operating System. The original name for the disk operating system that IBM chose to run its personal computers and called PC-DOS. Microsoft produced a version called MS-DOS. Many people refer to this operating system as simply DOS.

Scrapbook

A Macintosh utility that can be used to save text, graphics, or sounds for frequent use or for transfer from one file to another. Logos or letterheads could be stored in the Scrapbook.

screen capture

Screen capture is like taking a snapshot of the computer screen and whatever is on it at the time, and usually can be done with a keyboard command. It saves the screen image to a file on the hard drive, which can be opened with a graphics program.

screen dump

Printing whatever is on the computer screen.

screen font

A font that displays typeface characters on the computer screen. A different version of the font is needed (a printer font) to send the characters to the printer. The screen font looks like the printer font of the same name, so the user can see what the file looks like before printing.

screen phone

A device that looks similar to a standard desk telephone, but is equipped with a screen and a small keyboard for World Wide Web use.

screen saver

A program which automatically displays a moving picture or pattern on the computer screen after the computer has been idle for a certain period of time. If the keyboard or mouse is touched, the working desktop screen returns. The original purpose of a screen saver was to prevent a fixed image from being burned into the phosphor of the screen, by darkening the screen and displaying moving images. Screen burn is less likely to occur with current monitors, and would take many hours. But screen savers are fun, and users can get very creative programming different effects. One of the most famous screen savers is the one with flying toasters; there are many other effects such as underwater scenes, fireworks, stars and galaxies, etc.

screen shot

A snapshot of the computer screen and whatever is on it at the time, usually taken via keyboard commands. The screen image is saved as a file on the hard drive, which can be opened with a graphics program.

ScreenCam

A program from Lotus that can be used to make movies demonstrating how software works by moving through actions on the screen. Voice can be added, and a ScreenCam player can be included with the movie file so that it runs by itself.

screened-host firewall system

A firewall architecture in which a router is used to filter incoming and outgoing connections before sending them to the firewall.

scroll

To move through a document either up and down or sideways, in a continuous and smooth movement, as if the document were being rolled like a scroll. In many programs that use a graphical interface, there are arrows and bars to the sides of files which enable scrolling; other kinds of interfaces allow scrolling by various keyboard actions.

scroll arrow

An arrow on the side or bottom of a file that helps in scrolling. The mouse can be used to click on the arrow and move one line at a time; holding down the mouse button produces continuous scrolling.

scroll bar

A bar at the bottom or side of a window which is used to scroll through a document. It has a little movable box inside it (called a thumb, or elevator). Clicking inside the scroll bar moves the screen in jumps. Sliding the little box along the bar makes it possible to move quickly move up, down, left, or right, to a chosen point in the document.

scrollable window

A window that is not fully displayed on screen but can be scrolled up, down, or sideways to reveal its contents.

scrunch

To break through security to gain unauthorized access to a private network.

SCSI

Small Computer Systems Interface. (Pronounced “scuzzy”.) A high-speed interface that can connect to a computer devices such as hard drives, CD-ROM drives, floppy drives, tape drives, scanners, and printers. It was developed by Shugart Associates (now called Seagate). SCSI can connect up to seven devices; each one is given an identification number from 0 to 7, which is set with a manual switch. Newer versions of SCSI can connect up to 15 devices. The SCSI cable transfers eight bits at a time, in parallel.

SCSIProbe

A Macintosh control panel that can be used to find and mount a SCSI device.

scuzzy

The common pronunciation for SCSI (Small Computer Systems Interface).

SD

1. Sending Data. A modem status signal indicated by a flickering light on the modem, which means the local modem is sending data to a remote computer. 2. Single Density. Refers to the early floppy disks, made before double-density and high-density formats became available.

SD RAM

Synchronous Dynamic Random Access Memory (SDRAM). High-speed DRAM that adds a separate clock signal to the control signals. SDRAM can transfer bursts of non-contiguous data at 100 MBytes/sec, and has an access time of 8-12 nanoseconds. It comes in 64-bit modules: long 168-pin DIMMs.

SDDI

Sony Digital Data Interface.

SDK

Software Development Kit or Software Developers Kit. A set of tools to help programmers write new applications. The kit usually provides tools for creating menus, icons, dialog boxes, etc., and for interfacing the application with the operating system(s) it will be used with.

SDLC

Synchronous Data Link Control. A data transfer protocol used in IBM’s SNA networks. SDLC conforms to ISO’s High-level Data Link Control (HDLC) and ANSI’s Advanced Data Communication Control Procedures (ADCCP).

SDMI

Secure Digital Music Initiative. The recording industry has become increasingly concerned as new technologies for copying and distributing music over the Internet, such as MP3, have evolved. The Secure Digital Music Initiative was established to protect music companies' copyrights on the Web. Founded by the Recording Industry Association of America (RIAA), the initiative has support from major labels such as Universal, EMI, Sony, and Time Warner. The goal of SDMI is to create an open architecture and specification for digital music security, to insure interoperability among digital products as well as protect copyrighted music in various digital formats.

SDML

Signed Document Markup Language. A specification of a generic method for digitally signing a document, a section of a document, or multiple documents together. SDML requires the use of public key cryptography and can be used with web pages, e-mail messages or any text based documents. SDML is a generalization of the Financial Services Markup Language (FSML). SDML may be used for electronic funds transfer, electronic commerce, or any other signed contract or agreement.

SDRAM

Synchronous Dynamic Random Access Memory. High-speed DRAM that adds a separate clock signal to the control signals. SDRAM can transfer bursts of non-contiguous data at 100 MBytes/sec, and has an access time of 8-12 nanoseconds. It comes in 64-bit modules: long 168-pin DIMMs.

SDSL

Synchronous Digital Subscriber Line. A digital subscriber line that sends data at the same speed in both directions. SDSL is intended for business use, whereas ADSL (asynchronous digital subscriber line), in which data downloads much faster than it uploads, is mainly for home use. See also ADSL, DSL, HDSL.

SDSL

Symmetric Digital Subscriber Line. A technology that can send data at up to 3 Mbps over ordinary copper telephone lines. SDSL sends digital pulses in the high-frequency bandwidth not used by normal voice communications, which makes it possible to have voice and data transmissions over the same wires. SDSL is called symmetric because, unlike ADSL (asymmetric digital subscriber line), it has the same data rates for transmission from server to client and from client to server. A special SDSL modem is necessary.

SEA

Self Extracting Archive. A Macintosh archive format; it creates a file which automatically expands when a user double-clicks on its icon.

Seagate Technology, Inc.

A major independent manufacturer of hard disk drives, based in Scotts Valley, California.

search and replace

A computer function that searches for all instances of a particular set of characters and replaces it with a different set of characters determined by the user.

search engine

A program on the Internet that allows users to search for files and information.

search engines

Programs on the Internet that help users search for files and information. Examples are Infoseek, Yahoo, Lycos, Excite, and many more. Most search engines find files that contain a key word or words typed in by the user. Some search engines specialize in a subject area or type of file. Others, called meta-search engines, query a number of regular search engines and collect the best results.

search key

Data entered into a search engine indicating what the user wants to locate in its database.

Seattle Computer Products

Original developers of DOS, which was at first called SCP-DOS (Seattle Computer Products – Disk Operating System).

Seattle Computer Products – Disk Operati

(SCP-DOS). The original name for the disk operating system that IBM chose to run its personal computers and called PC-DOS. Microsoft produced a version called MS-DOS. Many people refer to this operating system as simply DOS.

SECAM

Sequential Couleurs a Memoire; also called Systeme Electronique Couleur Avec Memoire. The television broadcast standard used in France, the Middle East, and most of Eastern Europe. SECAM broadcasts an analog signal at 819 lines of resolution 25 interlaced frames a second, and uses sequential encoding of primary colors in alternating scan lines. PAL is the standard used in England and the rest of Europe; NTSC is used in the United States and Japan.

SECDEC

Single Error Correction, Double Error Detection.

second generation computer

A computer built with discrete transistors. Second-generation computers were made in the mid-1950s through mid-1960s.

second generation language

Assembly language; the language in between machine language and high-level programming languages.

secondary storage

Storage other than the computer's internal memory (RAM); external storage, such as disk or magnetic tape.

secret key encryption

A form of cryptography in which sender and receiver share a secret key.

sectors per track

(spt). Disk storage is organized in sectors, which are pie-shaped slices, and tracks, which are concentric rings. A combination of two or more sectors on a single track makes a cluster or block, the minimum unit used to store information. The number of sectors per track determines the size of each cluster. The number of clusters on a disk's surface determines the storage capacity of the disk. The number of sectors per track is also related to the speed at which a disk is read and the pattern of sector mapping.

Secure Digital Music Initiative

(SDMI). The recording industry has become increasingly concerned as new technologies for copying and distributing music over the Internet, such as MP3, have evolved. The Secure Digital Music Initiative was established to protect music companies' copyrights on the Web. Founded by the Recording Industry Association of America (RIAA), the initiative has support from major labels such as Universal, EMI, Sony, and Time Warner. The goal of SDMI is to create an open architecture and specification for digital music security, to insure interoperability among digital products as well as protect copyrighted music in various digital formats.

Secure MIME

(S/MIME or S-MIME). A public-key encryption protocol for MIME (Multipurpose Internet Mail Extensions) attachments to electronic mail messages.

Secure Sockets Layer

(SSL). A protocol from Netscape Communications Corporation, which is designed to provide secure communications on the Internet.

Security Administrator Tool for Analyzin

(SATAN). A freeware utility written by Dan Farmer and Wietse Venema that can be used to check a system for security vulnerabilities via the Internet.

security hole scanning

Looking for security holes in a system, usually with the intent of using the information to obtain unauthorized access.

see you see me

CU-SeeMe.

Sega

A Japanese company that manufactures popular video games and the equipment used to play them. Other products from Sega are mega-CDs, portable games, interactive products for PCs, and electronic theme parks.

select

To highlight an area of text or an image, or several items together. Areas of text can be selected with a mouse by dragging the cursor over them. Graphic elements (including text windows in a page layout program) are selected by clicking the mouse on them. Several elements can be selected together by clicking the mouse on each while holding down the shift key. Selected items can be moved or modified with other commands. On computers that do not have a mouse, the cursor is used for selecting, along with keyboard commands.

select all

A command that will select all the items on a page, or all the text within a window that the cursor is in.

selection list

A dialog box that has a scrollable list of choices from which the user can select one.

Self Extracting Archive

(SEA). A Macintosh archive format; it creates a file which automatically expands when a user double-clicks on its icon.

self-extracting file

A compressed file which automatically expands when executed. Often self-extracting files have the extension .SEA (self-extracting archive).

Semantic Web

The Web of data with meaning in the sense that a computer program can learn enough about what the data means to process it. (Tim Berners-Lee, from his book Weaving the Web, published 1999/2000)

semicolon

ASCII character 59: ; .

send to back

A feature in a page layout or graphics program that allows a particular graphic element to be selected and sent to the background; if the objects in front of it are opaque, the object sent to the back will be hidden or partly hidden. For example, a lightly screened box might be sent to the back, with a window of text sent to the front so it will show inside the box.

send to front

A feature in a page layout or graphics program that allows a particular graphic element to be selected and brought to the foreground; if the object is opaque, objects behind it will be hidden or partly hidden. For example, a light-colored box might be placed diagonally in front of a darker-colored box of the same size, to create the effect of a shadow. The light-colored box in this example is sent to the front.

septendecillion

10^54 (U.S. and Canada); 10^102 (Europe).

septet

A seven-bit byte.

septillion

10^24 (U.S. and Canada); 10^42 (Europe).

Sequenced Packet Exchange

(SPX). A Novell NetWare communications protocol used to transmit messages reliably over a network.

Sequent Computer Systems, Inc.

A computer manufacturer in Beaverton, Oregon that develops symmetric multiprocessing systems.

sequential

In consecutive order; for example, alphabetical, by date, or by number.

sequential access

A way of storing and retrieving information in sequence. For example, on a magnetic tape, which has sequential access, to get to a piece of information it is necessary to wind the tape up to that point. On a CD-ROM, which has random access, any file can be selected and accessed immediately in any order.

Sequential Couleurs a Memoire

(SECAM). Also called Systeme Electronique Couleur Avec Memoire. The television broadcast standard used in France, the Middle East, and most of Eastern Europe. SECAM broadcasts an analog signal at 819 lines of resolution 25 interlaced frames a second, and uses sequential encoding of primary colors in alternating scan lines. PAL is the standard used in England and the rest of Europe; NTSC is used in the U.S. and Japan.

serial

One at a time. In serial transmissions, one bit at a time is sent over the serial line.

serial computer

A computer with one processor that runs only one task at a time, executing instructions one after another, as opposed to a parallel computer that can run several processes at once.

serial device

Any hardware unit that is connected to a computer by plugging it into the serial port; for example, a modem, a keyboard, or a serial printer.

serial interface

A port on the computer that transmits data in serial form, one bit at a time, as opposed to a parallel interface which sends a number of bits side by side. Within the computer, data is transmitted over parallel lines, for greater speed; but telephone lines require serial transmission. The serial interface converts data from a parallel to a serial arrangement for sending to the modem. A serial interface is also used to connect a mouse, a scanner, and certain printers.

serial line

A transmission line which connects two serial ports, over which data is sent one bit at a time. A serial line can have two wires, so data can be transmitted and received at the same time.

Serial Line Internet Protocol

(SLIP). Software which uses the Internet Protocol (TCP/IP) over a serial line. SLIP makes it possible for a computer to communicate with other computers by means of a dial-up connection; for example, a serial port hooked to a modem that makes a connection between two local area networks or is used to access the Internet and World Wide Web.

serial mouse

The common mouse that is plugged into a PC serial port.

serial number

A number that uniquely identifies each hardware device or copy of software; the serial number for software is usually called a registration number. It is important to keep track of serial numbers, which are needed when calling for tech support, service, upgrades, etc.

serial port

A socket on a computer which is usually used to connect a modem, mouse, scanner, or serial printer. Sometimes two computers are connected together by their serial ports to send data between them. A serial port, also called a male connector, has 9 or 25 pins. A serial port sends information through a cable one bit at a time, whereas a parallel port sends eight bits at a time along parallel wires. A parallel port sends data faster but a serial port is reliable for transmission over a longer distance.

serial ports

Sockets on a computer that are usually used to connect a modem, mouse, scanner, or serial printer. Sometimes two computers are connected together by their serial ports to send data between them. A serial port, also called a male connector, has 9 or 25 pins. A serial port sends information through a cable one bit at a time, whereas a parallel port sends eight bits at a time along parallel wires. A parallel port sends data faster but a serial port is reliable for transmission over a longer distance.

serial printer

A printer connected to the computer by a serial port.

serial processing

Using a single processor to run one task at a time; also called sequential processing.

serial transmission

A way of transmitting information one bit after another, as opposed to parallel transmission in which a number of bits are transmitted at one time.

serialize

To convert a parallel arrangement of data (in which a number of bits are transmitted at a time along parallel channels) into a serial form (in which one bit at a time is transmitted); a serial interface provides this conversion to enable data transmission.

serif

A short finishing stroke at the end of and at an angle to each stroke in a letter. Serifs are found in typestyles such as Times Roman, Palatino, Garamond, and Baskerville. Serifs are thought to make type more readable, and are often used in book and newspaper text. Fonts without serifs are called san serif fonts.

server

The computer in a client/server architecture that supplies files or services. The computer that requests services is called the client. The client may request file transfer, remote logins, printing, or other available services.

server application

The software used by a server in providing a service to a client.

server-side image map

An image map in which the map that relates parts of the image to different URLs is stored on the server. See server-side include.

server-side includes

(SSI). The ability to include files from the server inside an HTML document by placing tags in the HTML file that link to those files. Using server-side includes makes it unnecessary to include multiple copies of the same information in the HTML file, and make it easier to work with frequently-updated information. Server-side includes are available on some HTTP servers.

service bureau

A business that sells such services as scanning, color printing, copying, color separations, and disk format conversion.

Service Level Agreement (SLA)

A contract between a network service provider and a customer that specifies the services the network service provider will furnish. Services SLAs may specify often include the percentage of time services will be available; number of users that can be served simultaneously; help-desk response time; and statistics to be provided. ISPs often provide SLAs for its customers.

service profile identifier

(SPID). A number that identifies a user's equipment for connecting to an ISDN (Integrated Services Digital Network) line.

servlet

An applet that runs on a server, usually meaning a Java applet that runs on a Web server.

session layer

Layer 5 of the Open Systems Interconnection (OSI) networking model, which handles logical connections between hosts; creates, maintains, and terminates a session; and handles security. It is a composite of the data flow control layer and transmission control layer.

set

A collection of elements which have some characteristic or characteristics in common; for example, the set of all rational numbers, the set of all even numbers greater than 20, or the set of all positive integers.

set theory

The theory of how sets are defined and how they interact. Three important interactions between sets are complement, union, and intersection.

set-top box

(STB). A box that sits on top of a television set and is the interface between the home television and the cable TV company. New technologies evolving for set-top boxes are video-on-demand, video games, educational services, database searches, and home shopping.

seven dwarfs

Univac, Burroughs, General Electric, Honeywell, RCA, National Cash Register, and Control Data Corporation. These companies were the main competitors to IBM in the early days of computing.

seven layer model

The Open Systems Interconnection model for communication which includes the physical layer, data link layer, network layer, transport layer, session layer, presentation layer, and application layer.

severity code

A code that classifies the seriousness of an error condition.

sex changer

A coupler with two male ends used to connect two female connectors, or a coupler with two female ends used to connect two male connectors.

sexadecimal

Early word for hexadecimal, the base 16 numbering system.

sexdecillion

10^51 (U.S. and Canada); 10^96 (Europe).

sextet

A six-bit byte.

sextillion

10^21 (U.S. and Canada); 10^36 (Europe).

SGI

Silicon Graphics, Inc. A Mountain View, California manufacturer of high-end graphics workstations and software, founded by James Clark, who later became head of Mosaic Communications Corporation.

SGML

Standard Generalized Markup Language. A generic language for writing markup languages. SGML makes possible different presentations of the same information by defining the general structure and elements of a document. HTML (Hypertext Markup Language) is based on SGML.

SGML application

A markup language written in SGML; HTML is an example. SGML (Standard Generalized Markup Language) is a meta-language – a language for writing markup languages.

SGRAM

Synchronous Graphic Random Access Memory. Memory that is used for graphic-intensive operations such as 3-D rendering and displaying full-motion video.

sh

Bourne shell. An early command interpreter and script language for UNIX, by S.R. Bourne of Bell Laboratories.

shadow mask

A thin metal plate full of holes that is behind the glass of a CRT screen. Electron beams are aimed through the holes and strike the phosphor coating on the inside of the screen. The purpose of the shadow mask is to keep the electron beams exactly aligned with their targets. The holes in most shadow masks are arranged in triangles; the Sony Trinitron has holes arranged in parallel slots.

shadow RAM

Shadow Random Access Memory. In a PC, an area of RAM in which a copy of the ROM Basic Input/Output System is stored, for faster access than the BIOS on the ROM chip.

Share and enjoy!

A statement found at the end of a README file for software, which means the software can be freely distributed and used.

shared logic

An arrangement in which two or more terminals close to each other share a computer that does the processing. Shared logic is commonly used with word processing applications.

shared resource

A peripheral device which is shared by more than one computer, such as a printer, disk, etc.

Shared Time Repair of Big Electronic Sys

(STROBES). A programming language used in testing computers.

shareware

Software that is copyrighted, but may be downloaded and used for a limited time for free, after which the user is asked to voluntarily send the author a small payment. Some shareware products offer additional features, documentation, technical support, and/or updates to registered users.

sharp

ASCII character 35: # . Also called hash mark or pound.

sheet feeder

A mechanical device attached to a printer which automatically feeds sheets of paper or forms from an input drawer into the printer, and which feeds the finished printed pages into an output drawer. Most printing instructions allow a choice between using the sheet feeder or the manual feed.

sheet-fed scanner

A scanner that feeds each sheet of paper across a nonmoving scan head; this is different from the flatbed scanner in which the paper is laid on a sheet of glass and the scan head moves. Obviously, a sheet-fed scanner can not be used to scan pages in books or magazines, or pages with pasted-on items.

shelf life

The period of time a material can “sit on the shelf” before it deteriorates and cannot be used.

shelfware

Software that gets bought by a company or individual that ends up sitting on a shelf somewhere and not being used.

shell

A software interface between the user and the computer's operating system. The shell interprets commands entered by the user, and passes them on to the operating system. DOS shells are COMMAND.COM and DOS shell; some UNIX shells are the Bourne shell (sh), the C shell (csh), and the Korn shell (ksh).

shell account

A dialup account with an Internet Service Provider that is based on a UNIX command-line interface.

shell extension

A computer’s shell is that part of the operating system that allows the user to access and manipulate the components of the computer’s hardware and software. A shell extension is a small system utility that allows a user to more easily access and configure the computer’s workings by tweaking the settings of the operating system.

shell script

A file containing commands to be carried out by the shell (the interface that passes commands to the operating system).

Sherlock

The name of the Find feature first used in Mac OS 8.5. It is used for locating files on the local computer, but also includes the ability to search any site on the Web that has a search engine. To use Sherlock to search a website, the user must place a plug-in file for the site in the Internet Search Sites folder of the System Folder.

SHF

Super High Frequency. Electromagnetic frequencies in the range of 3 to 30 gigaherz.

shielded twisted pair

(STP). Twisted pair cable that is wrapped in a metal sheath to provide extra protection from external interfering signals.

shift key

A keyboard key that, when held down, makes all the letters print as capitals, and the non-letter keys print other special characters such as the asterisk (*), ampersand (&), etc. The shift key is also used, alone or in combination with other keys, to give various commands to the computer.

shift register

A register in which all the bits can be moved one place to the left (or the right) when a particular control signal is pulsed. The shift register is used in binary multiplication and serial-parallel conversion, among other things.

Shocked

An adjective describing a Web page that uses Shockwave graphics.

Shockwave

A program, available as a plug-in, which enables a browser to view files created with Macromedia Director or Macromedia Freehand. Web pages that incorporate Shockwave effects are called “Shocked.”

Shockwave Flash

A file format for delivering interactive vector graphics and animations over the World Wide Web.

SHOE

Simple HTML Ontology Extensions. An extension to HTML which makes it possible for authors to include machine-readable semantic knowledge in World Wide Web documents. It includes mechanisms for hierarchical classification and for specifying relationships between elements and data. SHOE makes it possible for intelligent agents to gather information about web pages and other documents more intelligently, and thus to improve searching and knowledge-gathering.

short card

A PC expansion card that is half the size of a full-sized card, and fits in a short slot.

Short Messaging System

(SMS). A feature that allows users to receive or transmit short text messages using a wireless phone.

short-haul modem

A modem that can only transmit for a short distance (about a mile).

Shoutcast

Software for streaming MP3s. The official Shoutcast website has addresses for many stations which are like radio stations. You enter the URL in your MP3 player for the station you want, then the MP3s are downloaded while playing.

shouting

Using all capital letters in an email, chat or newsgroup message; CONSIDERED RUDE!

shovelware

Bonus software put on a CD-ROM to fill up extra space not needed by the main product.

show

In a graphical user interface, a menu selection that instructs the computer to show certain things on screen; for example, balloon help, the toolbox, guide lines, etc. The opposite command is “hide . . . “.

Show-And-Tell

A visual computer language for elementary school children.

ShrinkWrap

A Mac program from Aladdin that makes an exact copy of a CD, floppy, entire drive, or any type of file and turns it into a disk image on the desktop or for sending over the Internet. ShrinkWrap makes it unnecessary to load the actual CD, Zip, Jaz, SuperDrive or floppy disk; multiple CDs or disks are accessible on the desktop simultaneously.

SI

1. Systeme Internationale d'Unites, the international metric system. 2. Systems Integration. 3. Norton SI. 4. Macintosh SI.

sideband

A band of frequencies just above or just below a carrier frequency, produced by modulation of a carrier wave.

sidecar

A box attached to the outside a computer to add memory, expansion slots, hard drive controllers, or other expansions.

Sieve of Eratosthenes

An algorithm for finding prime numbers, used as a benchmark to measure the speed at which a computers does arithmetic.

SIG

Special Interest Group. A subdivision of a computer user group or other organization that meets to share information about an area of special interest. For example, SIGGRAPH is the special interest group of the Association of Computing Machinery that addresses computer graphics.

sig

Signature. A text file, usually only a few lines, which has the name of the user, and sometimes contact information, which is automatically attached to email messages and newsgroup postings. Some people include ASCII art, slogans, or favorite quotations in their signatures.

sig block

Signature (UNIX terminology). A text file, usually only a few lines, which has the name of the user, and sometimes contact information, which is automatically attached to email messages and newsgroup postings. Some people include ASCII art, slogans, or favorite quotations in their signatures.

sig quote

A quote a user puts within his or her electronic signature, which may be inspiring, humorous, opinionated, etc.

SIGARCH

The Special Interest Group for Computer Architecture of the Association of Computing Machinery.

Siggen Pro

A freeware program for generating signature files.

SIGGRAPH

A special interest group (SIG) of the Association of Computing Machinery that deals with computer graphics.

SIGhyper

A special interest group (SIG) of the SGML Users' Group that deals with hypertext and multimedia.

SIGMA

A NASA scientific program development tool.

sign off

To exit a computer system or network; same as log off.

sign on

To gain access to a computer system or network; same as log on. Signing on often requires the user to enter a password.

signal-to-noise ratio

(SNR). The amount of communication signal in relation to the amount of interference, or noise, on the medium. It is usually expressed in decibels.

signature

A text file, usually only a few lines, which has the name of the user, and sometimes contact information, which is automatically attached to email messages and newsgroup postings. Some people include ASCII art, slogans, or favorite quotations in their signatures.

Signed Document Markup Language

(SDML). A specification of a generic method for digitally signing a document, a section of a document, or multiple documents together. SDML requires the use of public key cryptography and can be used with web pages, e-mail messages or any text based documents. SDML is a generalization of the Financial Services Markup Language (FSML). SDML may be used for
electronic funds transfer, electronic commerce, or any other signed
contract or agreement.

SIGPLAN

The Special Interest Group on Programming Languages of the Association of Computing Machinery.

silicon

(Si). An element found in rocks and sand, which is used as the base, or substrate, for computer chips.

Silicon Alley

New York's equivalent of Silicon Valley; a region of many high-tech companies.

Silicon Dominion

Washington, DC's equivalent of Silicon Valley; a region of many high-tech companies.

Silicon Forest

Seattle's equivalent of Silicon Valley; a region of many high-tech companies.

Silicon Forest

The area around Seattle, Washington, where computer-related companies are located.

Silicon Graphics, Inc.

(SGI). A Mountain View, California manufacturer of high-end graphics workstations and software, founded by James Clark, who later became head of Mosaic Communications Corporation.

Silicon Hills

Austin's equivalent of Silicon Valley; a region of many high-tech companies.

silicon on sapphire

(SOS). A kind of computer chip that has a sapphire substrate covered with a thin layer of silicon.

Silicon Prairie

The area around Austin, Texas, where many hi-tech companies are located.

Silicon Valley

The area around San Jose, California, where many computer-related companies are located.

SIM

Society for Information Management. An organization for professionals in Management Information Services, formerly called Society for MIS.

SimCity

A simulation game from Maxis Software in which the object of the game is to design a city and manage it. SimCity is available for PC, Atari, Mac, Amiga, and Sun computers.

SimCity 2000

An advanced version of SimCity, the Maxis Software simulation game in which the object is to build a city and manage it well.

SIMD

Single Instruction/Multiple Data. A parallel processor that performs the same operations on different data. Also called data parallel.

SIMM

Single Inline Memory Module. A slim circuit board that holds Random Access Memory (RAM) chips. SIMMs can be plugged into sockets on the computer's motherboard to add memory to the computer. Depending on the computer, SIMMs may need to be installed in multiples of two or four.

Smallworldwide plc.

smart

In computer technology, a relative term, indicating how sophisticated a program or machine is and how many capabilities it has. A “smart missile” is one that is guided electronically, as opposed to a non-hi-tech missile; “smart modems” have more capabilities and can be programmed to make more decisions than earlier modems.

smart cable

A cable that has a microprocessor in it; it can assess incoming signals and convert them, if necessary, to the correct format.

smart card

A plastic card the size of a credit card that has an embedded microprocessor for storing information, used for banking, medical alerts, etc. It is used by inserting it into a reading device which is connected with a main computer.

smart installer

An installer that determines what configuration of software is needed by the current computer, and installs that version of the program.

smart terminal

1. A terminal that is part of a larger system and uses a main computer for storage of data, but has its own processing capability. 2. computer slang for a university.

Smartdrive

A DOS and Windows disk cache program from Microsoft. Typing SMARTDRV /S at the DOS prompt will display cache size and percentage of cache hits. The SMARTDRV line in the AUTOEXEC.BAT file can be used to set cache size.

SmartSuite

A software suite from Lotus which includes Ami Pro word processor, Lotus 1-2-3 spreadsheet, Freelance Graphics, Organizer personal information manager, and Approach database.

smash case

To automatically put all letters into uppercase or lowercase, regardless of how the text is entered. Some programs and interactive forms ignore case distinctions.

SMCC

Sun Microsystems Computer Corporation. See Sun Microsystems, Inc.

SMDS

Switched Multimegabit Data Service. A high-speed data communications service developed by Bellcore for connecting local area networks over the public telephone lines.

SMIL

Synchronized Multimedia Integration Language. A language developed by the W3C Synchronized Multimedia (SYMM) Working Group, that makes possible the broadcast of television-like content on the Web, and lowers the bandwidth needed for this kind of transmission. SMIL makes the production of audio-visual materials easy; users do not have to learn a programming language and can work with a simple text editor. SMIL uses XML syntax, and makes it possible to combine video, audio, text, graphic images, and hyperlinks.

smiley

Smiling face : ) (emoticon). Also used to refer to any emoticon.

smirkey

An emoticon that shows a smirking face, like :-, or }-) or :-} .

smoke and mirrors

Misleading marketing practices, similar to the illusions created in a magic show.

smoke test

A way of testing equipment by turning it on and seeing if it smokes.

smooth

This is a technique used by printers to make curves appear smooth. This is done by the size of the dots that make up the cure and the horizontal alingments of the dots affects the the cure by making it smooth.

SMP

Symmetric Multi-Processing. A computer system which has two or more processors connected in the same cabinet, managed by one operating system, sharing the same memory, and having equal access to input/output devices. Application programs may run on any or all processors in the system; assignment of tasks is decided by the operating system. One advantage of SMP systems is scalability; additional processors can be added as needed. However, in an SMP system, if one processor is down, the whole system is down.

SMPTE

Society for Motion Picture and TV Engineers, based in White Plains, New York. An standards organization for TV production, which developed SMPTE time code for audio and video.

SMPTE time code

Society for Motion Picture and TV Engineers time code. An eight-digit code for numbering each frame on videotape, in the form HH:MM:SS:FF (hours, minutes, seconds, frame number). SMPTE time code can be used to locate an exact frame, and to synchronize video and audio.

SMS

(Short Messaging System). A feature that allows users to receive or transmit short text messages using a wireless phone.

SMS

1. (Short Messaging System or Short Message Service). A feature that allows users to receive or transmit short text messages using a wireless phone. Using SMS, a short alphanumeric message, up to 160 characters, can be transmitted to a mobile phone, which displays the message as a pager would. 2. Storage Management Services. Software that can be used to back up data on a network by routing it to designated storage locations.

SMTP

Simple Mail Transfer Protocol. A server-to-server protocol for delivering electronic mail. The standard protocol used on the Internet; also used on other TCP/IP networks.

SMTP host

Simple Mail Transfer Protocol host. The location where outgoing electronic mail is dropped off, analogous to the mail slot at the post office.

SNA

Systems Network Architecture. A networking protocol standard for IBM mainframes and IBM-compatible mainframes.

snail mail

Regular postal service mail, which is slower than electronic mail.

snap point

One of the points on a graphic or text block that are used to snap it to a grid line or guide line. The snap points define the edges of the text or graphic element. If a snap to feature is chosen, the item will be moved so the snap points are touching the closest grid line or guide line.

snap to grid

A feature that can be selected in a draw program that automatically moves a text block or graphic element so it touches a grid line, if the grid line is within a certain distance.

snap to guides

A feature that can be selected in a page layout program that automatically moves a text block or graphic element so it touches a guide line, if the guide line is within a certain distance.

SNAP/SHOT

System Network Analysis Program / Simulated Host Overview Technique.

sneakernet

A means of moving a file from one computer to another by putting it on a floppy disk and carrying it across the room (possibly while wearing sneakers).

sniffer

A software or hardware tool that monitors data packets on a network to make sure messages are arriving as they should and everything else is working right.

SNMP

Simple Network Management Protocol. The Internet standard protocol for network management software. Using SNMP, programs called agents monitor various devices on the network (hubs, routers, bridges, etc.). Another program collects the data from the agents. The database created by the monitoring operations is called a management information base (MIB). This data is used to check if all devices on the network are operating properly.

SNMP agent

Simple Network Management Protocol agent. Hardware and/or software which is used to monitor devices on a network. Data from an SNMP agent, contained in a management information base (MIB), helps in management of the network by showing whether all devices are operating properly.

SNMP v2

Simple Network Management Protocol version 2. An updated version of SNMP which has better security, automatic continuous feedback, and other improvements.

SNOBOL

String Oriented Symbolic Language. A programming language from Bell Labs used for string processing, compiler development, and pattern matching.

snow

Small flickering white spots on a computer display, that look like snow. These spots occur temporarily when the contents of video memory are changed too rapidly for the display electronics to immediately register the new image.

SNR

Signal-to-Noise Ratio. The amount of communication signal in relation to the amount of interference, or noise, on the medium. It is usually expressed in decibels.

SO-DIMM

Small Outline Dual Inline Memory Module. A memory module that is half the size of a DIMM, and has 72 pins; often used in notebooks.

SOAP

Simple Object Access Protocol (SOAP) is a way for a program running in one kind of operating system (such as Windows 2000) to communicate with a program in the same or another kind of an operating system (such as Linux) by using the World Wide Web’s Hypertext Transfer Protocol (HTTP)and its Extensible Markup Language (XML) as the mechanisms for information exchange. SOAP specifies exactly how to encode an HTTP header and an XML file so that a program in one computer can call a program in another computer and pass it information. It also specifies how the called program can return a response.

soc

Top-level newsgroup category for a newsgroup on social issues.

social engineering

Breaking an organization’s security by interactions with people; for example, tricking someone into giving out a password.

Society for Information Management

(SIM). An organization for professionals in Management Information Services, formerly called Society for MIS.

Society for Motion Picture and TV Engine

(SMPTE). An standards organization for TV production, based in White Plains, New York, which developed SMPTE time code for audio and video.

socket

1. A hardware receptacle for a plug. 2. A communication path between two computer processes on the same machine or different machines. On a network, sockets serve as endpoints for exchanging data between computers. Each socket has a socket address, which is a port number plus a network address. Network connections are established by a socket device driver.

socket 7

The socket where the CPU is connected to the motherboard, on 486 and Pentium systems.

soft boot

Restarting the computer without turning the power off. The opposite of hard boot.

soft copy

The version of a document which is stored on a computer disk or similar medium, as opposed to the hard copy which is the paper printout.

soft font

A font that is on the computer's or printer's hard disk, and must be downloaded to the printer before printing.

soft hyphen

A hyphen that will only be set if the word falls at the end of a line which is too long, and has to be broken. Contrast hard hyphen.

soft page break

A page break automatically created by a word processing or report program
after the page reaches a certain length. The user can control the standard page length.

SoftPC

PC emulation software from Insignia Solutions, Inc. SoftPC enables Macintosh and UNIX workstations to run DOS and Windows programs.

software

Software is the computer program that tells a computer's hardware what to do. System software is the operating system that controls the basic functioning capabilities of the computer, network software enables multiple computers to communicate with one another, and language software is used to develop programs. Compare with hardware. See also shareware, freeware.

Software and Intelligent Systems Office

A U.S. Department of Defense (DoD) agency. In 1991, the Information Science and Technology Office (ISTO) was divided into the Software and Intelligent Systems Office and the Computing Systems Technology Office (CSTO).

software audit

A periodic check of computers in an organization to see if all the software installed is licensed.

software bloat

A condition where software, through adding features in successive versions, becomes so elaborate that it takes up too much memory and is too complicated to use.

Software Description Database

A database of software available on the Internet, with short descriptions, which can be accessed via Archie.

software developers kit

(SDK). A set of tools to help programmers write new applications. The kit usually provides tools for creating menus, icons, dialog boxes, etc., and for interfacing the application with the operating system(s) it will be used with.

software development kit

(SDK). A set of tools to help programmers write new applications. The kit usually provides tools for creating menus, icons, dialog boxes, etc., and for interfacing the application with the operating system(s) it will be used with.

software failure

A crash or cessation of processing because of a logic error in a program.

software handshake

Handshaking signals between two computers which are carried by way of extra characters inserted into the data stream; for example, Control-Q (ASCII character 17) for start and Control-S (ASCII character 19) for stop. A hardware handshake communicates the same information by voltage levels or pulses on wires. Computers use handshaking signals to indicate to each other when to start or stop sending data.

software house

A company that creates custom software for specific clients.

software license

A license issued to a person or company who buys a computer program, by the publisher, stating under what conditions the software may be used. Most licenses specify that the user may create a backup for personal use, but only one copy of the software may be used on one machine at a time. Site licenses allow unlimited copying of software within an organization, and charge for the extra use.

software package

An application program or group of programs developed for the general public. Rather than being custom designed for a specific user or company, the software is designed to meet the needs of a variety of users.

software piracy

The illegal copying of software for personal or commercial use.

software pirate

A person or company who makes illegal copies of software for personal or commercial use.

software publisher

A company that develops and markets software for public use.

Software Publishers Association

(SPA). A Washington, D.C. trade organization that supports enforcement of software copyrights.

software suite

A collection of programs sold together as one package. For example, an office software suite might include a word processor, a spreadsheet, a presentation program, and a database program. Some software suites are Lotus SmartSuite, Novell PerfectOffice, and ClarisWorks. Some advantages of buying software as a suite: It costs less to buy the software as a suite than to buy each program separately; the programs in a suite have a similar look and way of operating, making them easier to learn; programs in a suite are compatible for exchanging data and interacting with each other.

software theft

The unauthorized copying of software for personal or commercial use.

software tool

A program used for developing, compiling, or debugging other software.

SoftWindows

Software from Insignia Solutions that allows PowerPC and UNIX to emulate Windows applications.

SOH

Start Of Header. ASCII character 1: Control-A.

SOHO

Small-Office / Home-Office. An acronym referring to small businesses and home-based businesses as a market segment.

Solaris

A UNIX-based operating system and window system for Sun SPARC computers, formerly called SunOS. It includes the Open Look and Motif graphical user interfaces, OpenWindows (the Sun version of X Windows),
DOS and Windows emulation, and ONC networking. It is often used for server operating systems.

solid state

Using solid materials, and the electric and magnetic effects within them, rather than mechanical operation; semiconductors, integrated circuits, and transistors are solid state components.

solid state component

A component which operates through the control of electric or magnetic activity in solids; for example, a crystal diode or a semiconductor.

solid state computer

A computer that uses solid state components, such as semiconductors, rather than electron tubes. The use of solid state components began with second-generation computers.

SONET

Synchronous Optical Network. An ANSI standard for broadband public networks using fiber optics, initiated by the regional Bell operating companies (RBOCs). SONET makes it possible for telecommunications products from different vendors to communicate over networks, with data transmission rates from 51.84 Mbps to 48 Gbps.

sort

To organize information in the desired order. Some computer programs, for example, database and word processing programs, have sort functions which can organize items alphabetically, numerically, or by date, in ascending or descending order.

SOTS

Slap On The Side. External hardware attached to a computer to add memory, expansion slots, etc.

Sound Blaster

Popular PC sound cards from Creative Labs, Inc., Milpitas, CA.

sound board

A plug-in circuit board that enables a computer to record and play back sound. Sound boards may include a MIDI interface, a CD-ROM drive controller, and an audio amplifier for speakers.

sound card

An add-on expansion board that improves a computer's sound quality, and adds other sound capabilities. A sound card makes it possible to use speakers, a stereo, and a microphone to record and play sound; some sound cards also include MIDI.

sound player

A browser helper application that plays sound files, such as RealAudio or SoundMachine.

source code

A computer program written by a programmer in a source language. Source code is input to a compiler or assembler, in order to derive object code (machine code).

source computer

1. The computer in which a program is assembled or compiled for use by another computer (called the target computer). 2. The computer that originates a transmission.

source data

Original data which is input into a computer by the user or which comes from a source program.

source directory

The directory from which data is read.

source disk

The disk from which data is read.

source diskette

The diskette from which data is read.

source drive

A drive from which data is read.

source language

The language a source program is written in, and from which object language is translated.

source program

A program in the original language as written by the programmer, which must be translated into a machine-language object program for the computer to run it.

source route

An address for electronic mail in which the route for the message to take is defined at its source, and listed as a hierarchy of hostnames; for example: abc!def!ghi!jkl or [email protected] Usually routing of a message is determined at each stage along the way, based on current traffic on the network.

SPA

Software Publishers Association. A Washington, D.C. trade organization that supports enforcement of software copyrights.

space

1. ASCII character 32: the space character. 2. A 0 bit (a 1 bit is called a mark).

space bar

The long bar on the keyboard, which, when pressed, enters ASCII character 32: a blank space. It is usually pressed with one of the thumbs.

Spacewar

A space-combat simulation game originated in the 1960s, using imagery from E.E. Smith's Lensman science-fiction books.

SPAG

Standards Promotion and Application Group. A group of European OSI manufacturers which publishes the Guide to the Use of Standards (GUS).

spaghetti code

A computer program written in a disorganized and confusing way, using a lot of GO TO statements; following a tangled path like a plateful of spaghetti.

spam

The electronic equivalent of junk mail. See spamming.

spamdex

To stuff a web page full of words in the hope of making it high on the list for search engine robots. Sometimes a web page will have a list of many words, or the same word repeated many times, with the text in the same color as the background. Spamdexing will cause a web page to be kicked from search engine indexes.

spamdexing

Stuffing a web page full of words in the hope of making it high on the list for search engine robots. Sometimes a web page will have a list of many words, or the same word repeated many times, with the text in the same color as the background. Spamdexing will cause a web page to be kicked from search engine indexes.

spamming

The practice of sending copies of a message to many different newsgroups, with no regard to whether the subject matter is appropriate; or sending the same message by email to large numbers of people indiscriminately. Sometimes spams are advertisements. Spamming is considered bad netiquette and very unethical because it not only wastes everyone's time, but also costs money. The sender of the messages does not pay the cost; it is paid by the sites of the recipient and others on the route. Spamming often results in angry email replies from the targeted recipients.

spanned record

A set of related data which spans more than one block.

SPARC International, Inc.<SUP>&amp

The organization that licenses the SPARC® microprocessors; they also issue a newsletter and provide the public with information on the compatibility of SPARC® machines.

"SPARC® is a registered trademark of SPARC International, Inc. in the U.S. and other countries."


SPARC<SUP>®</SUP>

Scalable Processor Architecture. A high-speed RISC microprocessor developed by Sun Microsystems. It is used in Sun workstations, and has been adopted by some other computer manufacturers.

"SPARC® is a registered trademark of SPARC International, Inc. in the U.S. and other countries."


SPARCstation<SUP>®</SU

A group of workstations from Sun Microsystems that have SPARC® high-speed microprocessors.

"SPARC® is a registered trademark of SPARC International, Inc. in the U.S. and other countries."


sparse array

An array in which most of the elements are zero.

sparse file

A file that has empty spaces where data can be entered in the future.

sparse matrix

A matrix in which most of the elements are zero.

sparse vector

A vector in which most of the elements are zero.

spatial data

Data in the form of two- or three-dimensional images.

SPDL

Standard Page Description Language. An Open Document Architecture standard for a page description language, used to indicate how a document will be printed or displayed.

SPEC

Standard Performance Evaluation Corporation. A California nonprofit organization that maintains standardized performance tests, called benchmarks, for computers; developers of the SPECmark suite of benchmarks.

SPEC CFP92

A series of 14 test programs from SPEC, used to measure the floating point computation of a computer.

SPEC CINT92

A suite of six benchmarks from SPEC, which can be used to test a computer's performance of integer computations.

SPEC rate

A Standard Performance Evaluation Corporation (SPEC) benchmark result that is used to measure throughput of more than one copy of a test in a given time; useful for testing multiprocessor systems. SPEC rate is measured in comparison to the VAX 11/780.

SPEC ratio

The ratio of a computer's speed in performing a SPEC benchmark to the speed of a VAX 11/780 performing the same test.

SPECfp

Standard Performance Evaluation Corporation (SPEC) benchmark for floating point computation.

Special Interest Group

(SIG). A subdivision of a computer user group or other organization that meets to share information about an area of special interest. For example, SIGGRAPH is the special interest group of the Association of Computing Machinery that addresses computer graphics.

special-purpose computer

A computer designed for one specific use. Most computers are general-purpose computers, and can be programmed to do many different kinds of jobs.

specific markup

Adding commands in the text of a document which give specific instructions for formatting, such as type size, type style, center or justify type, etc., as opposed to generic markup which only defines general document elements.

SPECint

Standard Performance Evaluation Corporation (SPEC) benchmark for integer computation.

SPECmark

A suite of 10 benchmarks from Standard Performance Evaluation Corporation (SPEC) that test a computer's integer and floating point computation. One SPECmark is comparable to the performance of a VAX-11/780.

SPECmark89

A 1989 version of SPECmark, now superseded by CINT92 and CFP92.

specs

Specifications; detailed, usually written, plans for something. This term denotes, among other things, the specifications for styling a printed page (fonts, leading, type size and style, etc.), and the specifications for the components of a computer system.

Speech Application Programming Interface

(SAPI). An application programming interface from Microsoft that enables speech synthesis and speech recognition programs to communicate with the Windows 95 operating system.

speech recognition

The ability of a computer to recognize spoken words. Speech recognition can be used to dictate text or to give commands to the computer, and is helpful for people who are unable to type. The way it works is that spoken words are converted into digital data and matched to words already in the computer's dictionary.

Speech Recognition Application Program I

(SRAPI). An application programming interface from Novell, Inc., that facilitates speech recognition with WordPerfect 7.0 and Perfect Office 7.0.

speech synthesis

The generation of speech by a machine, from text input. Speech synthesis is used to enable blind users to read text. Synthesized speech is not hard to recognize, because it lacks normal spoken inflection.

speed buffering

Using a buffer area to make up for differences in speed between input and output. Data received into the buffer is output at the appropriate speed.

speedometer

A device that measures the speed of execution of a computer, usually represented as an LED display.

spelling checker

A computer program that checks the spelling of a document by comparing all the words to the words in its dictionary. The user can add words to the dictionary.

spelling flame

A newsgroup posting that corrects the spelling of a previous posting as a way of making the implication that the previous posting and its writer are ignorant.

Sperry Corporation

A company important in the history of computing. In 1910, Sperry Gyroscope Company was founded to manufacture and sell navigational equipment. Sperry Corporation was formed in 1933. In 1955, Sperry merged with Remington Rand to form Sperry Rand. In 1960, Sperry introduced its 1100 series computer. The 1108, which appeared in 1965, was the first multiprocessor computer. In 1976, Sperry introduced the first cache memory disk subsystem. In 1986, Sperry introduced its 2200 series, forerunner of the ClearPath HMP IX system. Sperry merged with Burroughs the same year to form Unisys Corporation.

SPID

Service Profile Identifier. A number that identifies a user's equipment for connecting to an ISDN (Integrated Services Digital Network) line.

spider

A program that searches the World Wide Web automatically by retrieving a document and all documents linked to it.

spike

A sudden pulse of extra voltage, lasting a fraction of a second, which can cause the computer to crash and damage files or computer components if there is no surge protector on the line. A burst of extra voltage that lasts longer, perhaps several seconds, is called a surge.

Spin Doctor

A challenging computer game in which the player must navigate through an obstacle course of various moving and spinning objects, mostly combinations of balls and sticks, with increasing levels of difficulty.

spin the Web

1. Slang term for browsing the World Wide Web. 2. Participate in creation of the World Wide Web network and its diverse resources.

spindle

The rotating shaft that turns a disk in a drive.

splash screen

On the Macintosh, an introductory screen that appears when opening a program; it usually contains a logo, author credits and copyrights, and contact information for the software company.

spline

A smooth curve that connects a set of points.

split screen

Displaying two or more independent areas of data on screen at the same time. The split screen may be used to have two or more separate files open in the same program or different programs; or it may be used to view different sections of the same file, as in a database or spreadsheet. For example, a spreadsheet may be too wide to see all the columns at one time; a split screen can be used to show a right-hand column at the same time as columns from the left side of the document. Each area of a split screen can be controlled independently.

spoofer

A program used by a cracker to trick a computer system into thinking it is being accessed by an authorized user.

spool

Simultaneous Peripheral Operation On-Line. To perform a peripheral operation while the computer is busy with other work. The most common use of spooling is with the printer; files are sent to the print spooler, which organizes a queue and then prints one file after another.

spool file

A file used to temporarily store data for later processing.

spooler

Software or hardware used to temporarily store data and process it later; for example, a print spooler which stores files to be printed when the printer is available.

spooling

Storing certain input or output on disk for low-speed processing while allowing the computer to continue its normal operations. Spooling is used for printers, plotters, sending email, and other peripheral operations. For example, a file to be printed is sent to the print spooler to wait its turn in the print queue until the printer is ready. Transferring data to the spooler is much faster than printing. While waiting for the file to print, the user can continue to input data, edit files, create new files, etc.

spreadsheet

A table which displays numbers in rows and columns, used for accounting, budgeting, financial analysis, scientific applications, and other work with figures. Originally, paper spreadsheets were used; the computerized versions have the advantage of being able to perform automatic calculations on changing data. Each location in a spreadsheet is called a cell, and each cell has a number, such as A3, B4, etc. The value of a cell may be calculated from a formula involving other cells; for example, C5 may be the sum of A5 and B5. If the data entered in A5 changes, then C5 would be automatically recalculated by the program. This feature makes it possible to use a spreadsheet to project the results of a change in one or more factors. References between cells may be designated as absolute or relative; an absolute reference refers to a specific cell, and a relative reference describes a cell in its relation to the current cell (as two rows above, two columns to the left, etc.). The data within a cell may be a label, a number, or a formula, and may be copied to other cells. There are two- and three-dimensional spreadsheets. The first commercially available spreadsheet program was VisiCalc for Apple II; now there are spreadsheet programs from Microsoft, Borland, Lotus, and many other companies. Microsoft Excel and Lotus 1-2-3 are popular examples.

spreadsheet program

A program which displays a table of numbers in rows and columns, used for accounting, budgeting, financial analysis, scientific applications, and other work with figures. Originally, paper spreadsheets were used; the computerized versions have the advantage of being able to perform automatic calculations on changing data. Each location in a spreadsheet is called a cell, and each cell has a number, such as A3, B4, etc. The value of a cell may be calculated from a formula involving other cells; for example, C5 may be the sum of A5 and B5. If the data entered in A5 changes, then C5 would be automatically recalculated by the program. This feature makes it possible to use a spreadsheet to project the results of a change in one or more factors. References between cells may be designated as absolute or relative; an absolute reference refers to a specific cell, and a relative reference describes a cell in its relation to the current cell (as two rows above, two columns to the left, etc.). The data within a cell may be a label, a number, or a formula, and may be copied to other cells. There are two- and three-dimensional spreadsheets. The first commercially available spreadsheet program was VisiCalc for Apple II; now there are spreadsheet programs from Microsoft, Borland, Lotus, and many other companies. Microsoft Excel and Lotus 1-2-3 are popular examples.

Spring Cleaning

A Mac program from Aladdin used to clean up a hard disk by eliminating duplicate files, uninstalling old applications, and cleaning the preferences folder of old, useless files.

Sprintnet

A public network whose users have access to online services such as CompuServe, Delphi, Portal, and GEnie.

sprite

A small graphic image on the computer screen, that can be moved around independently with a mouse or with keyboard commands. Examples are the ordinary cursor in its many forms, and the characters in video games.

SPS

Standby Power System. An offline backup power supply system which automatically switches on in case of power failure.

spt

Sectors Per Track. Disk storage is organized in sectors, which are pie-shaped slices, and tracks, which are concentric rings. A combination of two or more sectors on a single track makes a cluster or block, the minimum unit used to store information. The number of sectors per track determines the size of each cluster. The number of clusters on a disk's surface determines the storage capacity of the disk. The number of sectors per track is also related to the speed at which a disk is read and the pattern of sector mapping.

SPX

Sequenced Packet Exchange. A Novell NetWare communications protocol used to transmit messages reliably over a network.

spyware

Software that sends information about your Internet sessions back to the computer from which it’s launched. Spyware is often built into free downloads and works in the background without a user’s knowledge. Since it doesn’t record an individual’s personal information, it’s often used to create marketing profiles based on surfing habits.

SQL

Structured Query Language (pronounced SQL or Sequel). A language used to create, maintain, and query relational databases. It is an ISO and ANSI standard. SQL uses regular English words for many of its commands, which makes it easy to use. It is often embedded within other programming languages.

SQL Module Language

Structured Query Language Module Language. An ANSI standard programming language which can be used to interface other programming languages with SQL database management systems.

SQL Server

Structured Query Language Server. A client/server relational database management system from Sybase, Inc. for Windows NT, OS/2, UNIX, VAX, and NetWare servers.

square tape

Magnetic tape in rectangular cartridges instead of on round reels. Quarter-inch cartridges for personal computers and magnetic tape cartridges for mainframe computers are both in this format.

Squeak

A programming language used to communicate with the computer mouse.

SRAM

Static Random Access Memory. A kind of random access memory that requires a constant supply of power in order to hold its content, but does not require refresh circuitry as dynamic random access memory (DRAM) does. Each static RAM bit is a flip-flop circuit made of cross-coupled inverters; the activation of transistors controls the flow of current from one side to the other. Unlike read-only memory (ROM), SRAM will lose its content when the power is switched off. Static RAM is usually faster than dynamic RAM, but takes up more space and uses more power. It is used for the parts of a computer that require highest speed, such as cache memory.

SRAPI

Speech Recognition Application Program Interface. An application programming interface from Novell, Inc., that enables the speech recognition features of WordPerfect 7.0 and Perfect Office 7.0 to communicate with the computer’s operating system.

SS

Single Sided. Refers to a floppy disk that can only store data on one side.

SSBA

Suite Synthetique des Benchmarks de l'AFUU. An AFUU (French Association of Unix Users) public domain benchmark suite.

SSCP

System Services Control Point. Software that manages all resources in a mainframe-based Systems Network Architecture (SNA) network.

SSDD

1. Single Sided Double Density. An old floppy disk format that had data stored only on one side. Double-density meant twice the storage space of the older single density format. 2. Same Stuff, Different Day.

SSI

1. Small-Scale Integration. The use of integrated circuits with less than 100 logic gates, as in the early third-generation computers. 2. Server Side Includes. The ability to include files from the server inside an HTML document by placing tags in the HTML file that link to those files. Using server-side includes makes it unnecessary to include multiple copies of the same information in the HTML file, and make it easier to work with frequently-updated information. Server-side includes are available on some HTTP servers.

SSL

Secure Sockets Layer. A protocol from Netscape Communications Corporation, which is designed to provide secure communications on the Internet.

ST connector

A type of connector for fiber-optic cable that uses a bayonet mount and connects one optical fiber. It has been widely used in commercial wiring.

stack

A data structure used to store items which are retrieved in last-in first-out order (LIFO). A stack can be used to keep track of the sequence of subroutines called in a program. Data is entered or retrieved by “pushing” a new item onto the stack or “popping” the top item off the stack.

stack overflow

An error condition that is the result of trying to put additional items onto a stack when there is no room for them. See stack.

stack underflow

An error condition that results from trying to retrieve an item from an empty stack. See stack.

stacking order

The order of a series of overlapping windows, meaning which one is in front (or on top), which one is in back (on the bottom), and the order of the windows in between.

Stallman, Richard M.

(RMS). Founder of the GNU project and Free Software Foundation.

stand-alone modem

An external modem; a modem that is separate from the computer.

stand-alone system

A system that can run programs independently. It may access data from other systems sometimes.

stand-alone workstation

A workstation that can do its own processing independent of a server or host system.

standard

An agreed-upon set of specifications for hardware or software. Agreeing upon standards makes it possible for different manufacturers to create products that are compatible with each other. Standards may be set by official standards organizations, or they may be unofficial standards that are established by common use.

Standard for Robot Exclusion

World Wide Web Robots (which are also called spiders or wanderers) are programs that traverse many pages in the World Wide Web searching for information. There have been occasions where robots have visited web servers where they were not wanted for one reason or another. Some robots overwhelmed servers with rapid-fire requests, or requested the same files again and again. Another problem was robots visiting parts of web servers that were not appropriate, such as very deep virtual trees, duplicated or temporary information, or cgi scripts that had side effects such as voting. The need became evident for established mechanisms that would allow web servers to tell robots which parts of their server not to access. The Standard for Robot Exclusion is a way robot authors can cooperate to protect web servers against unwanted accesses by robots.

Standard Generalized Markup Language

(SGML). A generic markup language for document formats. SGML makes possible different presentations of the same information by defining the general structure and elements of a document. HTML (Hypertext Markup Language) is based on SGML.

standard input/output

The default input and output channels for a UNIX operating system. Standard input comes from the terminal or keyboard, and standard output goes to the terminal. Either can be redirected to a file or other process.

Standard MIDI File

(SMF). A MIDI file created using the General MIDI Standard.

Standard Page Description Language

(SPDL). An Open Document Architecture standard for a page description language, used to indicate how a document will be printed or displayed.

Standard Performance Evaluation Corporat

(SPEC). A California nonprofit organization that maintains standardized performance tests, called benchmarks, for computers; developers of the SPECmark suite of benchmarks.

Standards Promotion and Application Grou

(SPAG). A group of European OSI manufacturers which publishes the Guide to the Use of Standards (GUS).

Standby Power System

(SPS). An offline backup power supply system which automatically switches on in case of power failure.

Star

The first computer with a graphical user interface, made by Xerox but never successfully commercialized. It was the inspiration for the Apple Macintosh computers, X Windows, Sun workstations, and later Xerox computers.

star network

A network configuration in which each node is connected to a separate line, and all lines lead to the same central hub. From the central station any line can be connected to any other line. An example is a PBX (private branch exchange).

StarBurst

A database management system (DBMS) from IBM.

start bit

A bit which is sent to signal the beginning of a data transmission on a serial line.

start of header

(SOH). ASCII character 1: Control-A.

start of text

(STX). ASCII character 2: Control-B.

start/stop transmission

A way of transmitting data in which one character is sent at a time, and there may be uneven amounts of time between characters. A start bit and a stop bit notify the receiving computer when the transmission begins and ends. This is also called asynchronous transmission. It is different from synchronous transmission, in which strings of multiple characters are transmitted, and the sending and receiving of characters are controlled by timing signals.

startup disk

The disk that is used to start up the computer, also called a boot disk. The startup disk can be a floppy disk or hard disk, but must have the necessary information on it for booting the computer.

startup folder

In Windows 95, a folder containing programs that will automatically execute when Windows starts up.

Startup Items

A folder in Macintosh System 7; any files placed in this folder will open when the computer is started. For example, a startup screen, a sound file to be played when the computer first starts, a reminder calendar, or application programs can be startup items. Normally, an alias of a file is placed in this folder rather than the file itself.

startup movie

A movie clip that is set up to play automatically when the computer first starts up. The user can choose the movie clip.

startup screen

A screen that is automatically displayed when the computer starts up. It may have text or images, and can be programmed by the user.

startup volume

The disk that is used to start up the computer, also called a startup disk. The startup volume can be a floppy disk or hard disk, but must have enough of the computer’s operating system on it to start the computer.

STARTUP.CMD

(Startup Command). In the OS/2 system, a file that is executed when the computer is started.

state-of-the-art

Incorporating the newest and most advanced technology.

statement

An instruction in a high-level programming language, which may be translated into one or more machine code instructions by the computer.

static electricity

An isolated and nonmoving electric charge, such as is produced by friction in a low-humidity environment. The charge may be intentionally generated, as in an electrostatic printer.

Static IP Address

A static or dedicated IP Address is a type of account from an ISP where your computer(s) are assigned the same IP Address at all times. While this used to be a requirement for web-site serving, it is usually used today for security purposes.

static random access memory

(SRAM). A kind of random access memory that requires a constant supply of power in order to hold its content, but does not require refresh circuitry as dynamic random access memory (DRAM) does. Each static RAM bit is a flip-flop circuit made of cross-coupled inverters; the activation of transistors controls the flow of current from one side to the other. Unlike read-only memory (ROM), SRAM will lose its content when the power is switched off. Static RAM is usually faster than dynamic RAM, but takes up more space and uses more power. It is used for the parts of a computer that require highest speed, such as cache memory.

station

One of the nodes in a network.

status bar

A bar along the bottom of a window where information is displayed about the current application. It may tell the position of the cursor on the screen, the current date and time, the page number, etc. The information shown in the status bar changes with different programs and different commands.

status light

A little light on a computer or peripheral, usually an LED, which indicates the device is on, a drive is being accessed, or other information about the operating status. Modems have a row of lights that give information about the status of transmission.

status line

A strip along the bottom of a window where information is displayed about the current application. It may tell the position of the cursor on the screen, the current date and time, the page number, etc. The information shown in the status line changes with different programs and different commands.

STB

Set-Top Box. A box that sits on top of a television set and is the interface between the home television and the cable TV company. New technologies evolving for set-top boxes are video-on-demand, video games, educational services, database searches, and home shopping.

STD

Standard; refers to a set of documents (STD 1, STD 2, etc.) that define Internet standards.

STD 1

Standard 1. The official list of Internet standards defined by the Internet Architecture Board (IAB).

STD 15

Standard 15. A document which defines standards for Simple Network Management Protocol (SNMP).

STD 2

Standard 2. A document that lists current Internet Assigned Numbers.

STD 9

Standard 9. The document that defines standards for File Transfer Protocol (FTP).

stderr

Standard error. A UNIX designation. Like standard output, standard error also normally is sent to the terminal.

stdin

Standard input. The default input channel for a UNIX operating system, which is normally from the terminal or keyboard, but can be redirected to come from a file or connected by piping to another process.

stdio

Standard I/O (standard input/output). The default input and output channels for a UNIX operating system. Standard input comes from the terminal or keyboard, and standard output goes to the terminal. Either can be redirected to a file or other process.

stdout

Standard output. The default output channel for a UNIX operating system, which normally goes to the terminal, but can be redirected to go to a file or connected by a pipe to another process.

STDWIN

A graphical user interface with windows from CWI, available for Macintosh and X Windows.

stealth virus

A virus that has ways of hiding itself so it is hard to detect.

stepwise refinement

A way of developing a computer program by first describing general functions, then breaking each function down into details which are refined in successive steps until the whole program is fully defined. Also called top-down design.

stereogram

A two-dimensional image which seems to be three-dimensional if viewed a certain way (at a certain distance, focus, and angle).

stickiness

A measure of how long the average user spends at a website. In contrast to measuring hits, this measure provides an indication of how interesting the website itself is, rather than just how interesting the ad or link is that brings users to the site.

sticky menu

A menu that will stay open if the pointer is put in the correct position, which is sometimes to the left of it and sometimes to the right.

stiffy

Another name for the 3.5" floppy disk, which refers to the stiffness of the jacket compared to the more flexible 5.25" floppy.

STIK

Shirt, Tie, Keyboard. Computer slang for a boring corporate IS person; similar to ÒsuitÓ.

still frame

A single frame from a video, film, or CD-ROM, which shows a still picture.

stomp on

To overwrite by accident.

Stone Age

In computer jargon, the early period of first-generation computers.

stop bit

A bit which signals the end of a unit of transmission on a serial line. A stop bit may be transmitted after the end of each byte or character.

stoppage

A condition of being damaged to the point of unusability.

storage

A device into which data can be placed, held, and later retrieved. “Main storage” refers to the computer's memory, the space used for executing instructions; “auxiliary storage” refers to disks, diskettes, magnetic tape, and other media for holding data.

Storage Area Network (SAN)

A high-speed network that connects multiple storage devices so that they may be accessed on all servers in a Local Area Network (LAN) or Wide Area Network (WAN).

storage capacity

The amount of data a storage medium can hold; usually expressed in kilobytes, megabytes, or gigabytes.

storage device

A peripheral device for storing data. Tapes and disks are storage devices.

storage dump

A printout of whatever is in system storage at the time.

storage management services

(SMS). Software that can be used to back up data on a network by routing it to designated storage locations.

storage media

Any media used for storing data, such as hard disks, floppy disks, optical disks, or magnetic tape.

store

To copy or transfer data from the computer to a storage medium such as disk or tape.

store-and-forward routing

A way of transmitting messages in which each station along the path must receive the whole message before it can forward any of it to the next station. See wormhole routing.

STP

Shielded Twisted Pair. Twisted pair cable that is wrapped in a metal sheath to provide extra protection from external interfering signals.

Stratus Computer, Inc.

A computer manufacturer in Marlboro, Massachusetts, that makes the XA/R and XA/2000 computers.

streaming

Playing audio or video immediately as it is downloaded from the Internet, rather than storing it in a file on the receiving computer first. Streaming is accomplished by way of web browser plug-ins, which decompress and play the file in real time; a fast computer and fast connection are necessary.

streaming MP3

A technology that allows the user to listen to MP3s as they are downloading, rather than downloading a whole MP3 and then listening to it.

strikethrough

Letters that have a line through them as though they have been crossed out; sometimes used in advertising.

String Oriented Symbolic Language

(SNOBOL). A programming language from Bell Labs used for string processing, compiler development, and pattern matching.

STROBES

Shared Time Repair of Big Electronic Systems. A programming language used in testing computers.

stroke weight

The light, medium, or bold appearance of a typeface.

Structured Query Language

SQL (pronounced SQL or Sequel). A language used to create, maintain, and query relational databases. It is an ISO and ANSI standard. SQL uses regular English words for many of its commands, which makes it easy to use. It is often embedded within other programming languages.

strudel

ASCII character 64: @ . Also called the commercial at sign.

stub network

A network that carries packets to and from local hosts.

Stuffit

A Macintosh file compression utility from Aladdin Systems, available as shareware. Mac files downloaded from the Internet often are in Stuffit format, and can be decompressed with Stuffit Expander.

Stuffit Expander

The decompression program for the Macintosh Stuffit compression utility.

STX

Start Of Text. ASCII character 2: Control-B.

subclass

In object-oriented programming, a class, or object type, which inherits attributes and methods from another class (called a superclass).

subdirectory

A directory that is inside, or subordinate to, another directory. A subdirectory must be reached by going through all directories above it.

subfolder

A folder that is inside, and subordinate to, another folder.

subject line

In an electronic mail program, the short line of type that indicates what the message is about. Using a well-chosen subject line will help both the sender and receiver identify the subject of the message at a glance, without having to open and read it. Some email filtering programs can filter mail by subject line, so that all mail on a certain subject is filed, given high priority, or thrown out.

subnet

1. A part of a network, which has the same network address as other parts of the network but a unique subnet number; a subdivisional network interconnected and situated within a larger network. 2. Within the ISO/OSI reference model, the layers below the transport layer are referred to as the subnet. They consist of the network, data link, and physical layers.

subnet mask

A number used to identify a subnetwork when an IP address is shared by multiple networks.

subnotebook

A portable computer that weighs from two to six pounds. The subnotebook is smaller and lighter than a notebook computer, and has less storage space and a smaller screen.

subscript

Subscript characters are below the line of regular text and often smaller. Subscripts are used for chemical symbols (H2O) and mathematical formulae.

subset

A set that is included in another set, which is called a superset. The superset has all the characteristics of the subset and additional characteristics.

substitution cipher

A way of enciphering a message by replacing letters with other letters.

suffix notation

The same as reverse Polish notation. A way of expressing a sequence of calculations without using parentheses to show which operation must be performed first. For example, the expression 2(4+5), which instructs the reader to add 4 + 5 and multiply by 2, would be written 2 4 5 + * in suffix notation. To make the calculation, read from left to right until you find an operation, then perform the operation on the numbers immediately to the left of it, and continue to the next operation. So 2 4 5 + * becomes 2 9 * and then 18. See also Polish notation.

SUG

Sun User Group.

suit

An administrative or management person; someone who wears suits. Generally a term used by hackers and other non-suits.

Suite Synthetique des Benchmarks de l&#0

(SSBA). An AFUU (French Association of Unix Users) public domain benchmark suite.

Sun Microsystems, Inc.

One of the biggest U.S. computer manufacturers, based in Mountain View, California, founded in 1982. Sun is known for producing high-performance workstations, the Open Network Computing and Network File System software, and a version of UNIX called Solaris (formerly SunOS). Sun 2 and 3 workstations used Motorola 680×0 microprocessors; Sun 4 uses SPARC.

SunConnect

The division of Sun Microsystems that develops networks.

SunExpress

The division of Sun Microsystems responsible for distribution.

SunOS

A version of UNIX created for Sun workstations, later replaced by Solaris.

SunPics

The division of Sun Microsystems involved with printing and imaging.

SunPro

The division of Sun Microsystems that produces programming tools.

SunScan

Free Year 2000 compliance software from Sun Microsystems that scans Sun's hardware, operating environment, and software products and provides patches if needed.

SunSoft

The division of Sun Microsystems that produces system software.

SunView

A windows system from Sun Microsystems.

super 7

A socket similar to socket 7, but with better performance; the super 7 can handle a bus speed of 100 MHz.

super high frequency

(SHF). Electromagnetic frequencies in the range of 3 to 30 gigaherz.

Super VHS

SVHS (Super Video Home System). A high-quality video format that has higher resolution than normal VHS. It must be played on a videocassette recorder that supports the SVHS format, and to see the sharper image resulting from the higher resolution, it must be played on a high-resolution television set.

Super Video Graphics Array

(SVGA). A video display standard for color monitors, defined by VESA. SVGA monitors display up to 16.7 million colors with resolutions up to 1,280 x 1,024 pixels, and are good for multimedia applications.

Super-JANET

A further development of JANET, the UK educational and research network run by UKERNA. Super-JANET provides network facilities for new applications such as Multimedia Conferencing.

superclass

In object-oriented programming, a class, or object type, from which another class (called a subclass) inherits attributes and methods.

supercomputer

A very fast and powerful computer, outperforming most mainframes, and used for intensive calculation, scientific simulations, animated graphics, and other work that requires sophisticated and high-powered computing. Cray Research and Intel are well-known producers of supercomputers.

superconductor

A material that has almost no resistance to the flow of electricity. Superconductors work at very low temperatures.

SuperJanet

An upgrade of JANET (Joint Academic Network), a national high-speed broadband network created to support higher education and research in the United Kingdom.

superprogrammer

A very fast and effective programmer.

superscript

Superscript characters appear above the line of regular text and are often smaller. Superscripts are used for footnotes and exponents (r2).

superset

A set that includes other sets within it, which are called subsets. For example, a software or hardware upgrade may be a superset of the previous version in that it can do everything the previous version can do and more.

superuser

1. A privileged account with more powers than the ordinary user has on a system. 2. A user who is not a programmer or hacker, but is expert with some aspect of computing.

surf

1. To ride the waves in the ocean. 2. To navigate in cyberspace like a surfer riding the top of a wave.

surfing

By analogy with riding waves in the ocean, traveling from place to place on the Internet. The idea “Internet surfing” may come from “channel surfing” on the television, which means switching from channel to channel looking for something interesting. Recreational use of the Internet is similar.

surge

A sudden pulse of extra voltage, lasting a second or longer, which can cause the computer to crash and damage files or computer components if there is no surge protector on the line. A burst of extra voltage that lasts only a fraction of a second is called a spike.

surge protector

An electrical device that protects a computer from spikes and surges in the power line. All computers have some surge protection built in, but this protection is not always enough. External surge protectors come in the form of a unit that plugs into the wall, with outlets for several electrical plugs. However, not all outlet bars have surge protection.

surge suppressor

An electrical device that protects a computer from spikes and surges in the power line. All computers have some surge suppression built in, but this protection is not always enough. External surge suppressors come in the form of a unit that plugs into the wall, with outlets for several electrical plugs. However, not all outlet bars have surge suppression.

SVC

Switched Virtual Circuit. A network connection that is established from sender to receiver at the time of transmission, as in a switched public network. Contrast with PVC.

SVCD

Super Video CD. In many respects, SVCDs are upgraded versions of VCDs. SVCDs use MPEG as its compression standard and can hold between 35 to 60 minutes of full motion video on 74/80 min CDs. SVCDs can be played in DVD players, DVD-ROM and CD-ROM drives.

SVD

Simultaneous Voice and Data. The multiplexing of voice and data for transmission over an analog telephone line. Examples are MultiTech Supervisory Protocol (MSP) and Radish Communications VoiceView.

SVGA

Super Video Graphics Array. A video display standard for color monitors, defined by VESA. SVGA monitors display up to 16.7 million colors with resolutions up to 1,280 x 1,024 pixels, and are good for multimedia applications.

SVHS

Super VHS (Super Video Home System). A high-quality video format that has higher resolution than normal VHS. It must be played on a videocassette recorder that supports the SVHS format, and to see the sharper image resulting from the higher resolution, it must be played on a high-resolution television set.

swap file

Also called virtual memory. A portion of the hard drive set aside to use when more RAM is needed. Virtual storage is divided into segments called pages; each page is correlated with an address in physical memory. When the address is referenced, the page is swapped into memory; it is sent back to disk when other pages must be called.

switch

1. A communications device that controls the operation and routing of a signal path. 2. A circuit element which enables a device to be turned either on or off. 3. A networking device which can send packets directly to to port associated with a given network address.

Switched Multimegabit Data Service

(SMDS). A high-speed data communications service developed by Bellcore for connecting local area networks over the public telephone lines.

switched network

1. A network in which a temporary connection is established by closing a switch; an example is the ordinary telephone, where connections are made by dialing. 2. A packet-switched network, in which a temporary connection is established between points for transmitting data in the form of packets.

switched virtual circuit

(SVC). A network connection that is established from sender to receiver at the time of transmission, as in a switched public network. Contrast with permanent virtual circuit.

Sybase Corporation

A relational database management system (DBMS) vendor in Emeryville, California.

SyJet

A removable hard drive from SyQuest with over 1 GB storage. It is connected with the computer via a SCSI interface.

Symantec AntiVirus for Macintosh

(SAM). An antivirus program from Symantec Corporation, Cupertino, California.

SymbMath

Symbolic math software for MS-DOS.

Symbol font

A font that has Greek and other special characters useful, among other things, for mathematical formulas.

SYMM

Synchronized Multimedia. Productions that use a combination of synchronized multimedia elements such as audio, video, text, graphic images, and hyperlinks. One example is the broadcasting of television-like content on the World Wide Web. See also SMIL and SYMM-WG.

SYMM-WG

Synchronized Multimedia Working Group. A W3C working group that developed the SMIL 1.0 specification for bringing synchronized multimedia content to the Web. The working group is composed of experts in CD-ROM, interactive television, audio/video streaming, and the World Wide Web, from research organizations and technology companies.

symmetric digital subscriber line

(SDSL). A technology that can send data at up to 3 Mbps over ordinary copper telephone lines. SDSL sends digital pulses in the high-frequency bandwidth not used by normal voice communications, which makes it possible to have voice and data transmissions over the same wires. SDSL is called symmetric because, unlike ADSL (asymmetric digital subscriber line), it has the same data rates for transmission from server to client and from client to server. A special SDSL modem is necessary.

symmetric encryption

A form of cryptography in which sender and receiver have the same key.

symmetric key cryptography

In computer security, cryptography in which both ends have the same encryption key; it uses the same key for encryption and decryption.

symmetric multiprocessing

(SMP). A computer system which has two or more processors connected in the same cabinet, managed by one operating system, sharing the same memory, and having equal access to input/output devices. Application programs may run on any or all processors in the system; assignment of tasks is decided by the operating system. One advantage of SMP systems is scalability; additional processors can be added as needed. However, in an SMP system, if one processor is down, the whole system is down.

symmetric multiprocessor

A parallel processor which performs symmetric multiprocessing.

Symphony

An integrated software package from Lotus, an improvement on the Lotus 1-2-3 spreadsheet. Symphony includes speadsheet, business graphics, word processing, database management, report generation, and communications.

SyncDRAM

Synchronous Dynamic Random Access Memory (SDRAM). High-speed DRAM that adds a separate clock signal to the control signals. SDRAM can transfer bursts of non-contiguous data at 100 MBytes/sec, and has an access time of 8-12 nanoseconds. It comes in 64-bit modules: long 168-pin DIMMs.

synchronized multimedia

(SYMM). Productions that use a combination of synchronized multimedia elements such as audio, video, text, graphic images, and hyperlinks. One example is the broadcasting of television-like content on the World Wide Web. See also SMIL and SYMM-WG.

Synchronized Multimedia Integration Lang

(SMIL). A language developed by the W3C Synchronized Multimedia (SYMM) Working Group, that makes possible the broadcast of television-like content on the Web, and lowers the bandwidth needed for this kind of transmission. SMIL makes the production of audio-visual materials easy; users do not have to learn a programming language and can work with a simple text editor. SMIL uses XML syntax, and makes it possible to combine video, audio, text, graphic images, and hyperlinks.

Synchronized Multimedia Working Group

(SYMM-WG). A W3C working group that developed the SMIL 1.0 specification for bringing synchronized multimedia content to the Web. The working group is composed of experts in CD-ROM, interactive television, audio/video streaming, and the World Wide Web, from research organizations and technology companies.

synchronous

Capable of performing two or more processes at the same time, such as sending and receiving data, using a common timing signal.

Synchronous Data Link Control

(SDLC). A data transfer protocol used in IBM's SNA networks. SDLC conforms to ISO’s High-level Data Link Control (HDLC) and ANSI’s Advanced Data Communication Control Procedures (ADCCP).

synchronous digital subscriber line

(SDSL). A digital subscriber line that sends data at the same speed in both directions. SDSL is intended for business use, whereas ADSL (asynchronous digital subscriber line), in which data downloads much faster than it uploads, is mainly for home use. See also ADSL, DSL, HDSL.

Synchronous DRAM

Synchronous Dynamic Random Access Memory (SDRAM). High-speed DRAM that adds a separate clock signal to the control signals. SDRAM can transfer bursts of non-contiguous data at 100 MBytes/sec, and has an access time of 8-12 nanoseconds. It comes in 64-bit modules: long 168-pin DIMMs.

Synchronous Dynamic Random Access Memory

(SDRAM). High-speed DRAM that adds a separate clock signal to the control signals. SDRAM can transfer bursts of non-contiguous data at 100 MBytes/sec, and has an access time of 8-12 nanoseconds. It comes in 64-bit modules: long 168-pin DIMMs.

synchronous graphic RAM or synchronous g

(SGRAM, Synchronous Graphic Random Access Memory). Memory that is used for graphic-intensive operations such as 3-D rendering and displaying full-motion video.

Synchronous Graphic Random Access Memory

(SGRAM). Memory that is used for graphic-intensive operations such as 3-D rendering and displaying full-motion video.

synchronous key encryption

A method of encryption that uses two interlocking keys, designed so a message encoded using one key can be decoded using the other key. If one key is made public and the other kept private, then anyone who has the public key can send a message that can be decoded using the other key. The sender can add another layer of encryption by also encrypting the message with the sender's private key, so it has to be decoded first with the sender's public key and then with the receiver's private key. This is a powerful encryption method, of which PGP is an example.

Synchronous Optical Network

(SONET). An ANSI standard for broadband public networks using fiber optics, initiated by the regional Bell operating companies (RBOCs). SONET makes it possible for telecommunications products from different vendors to communicate over networks, with data transmission rates from 51.84 Mbps to 48 Gbps.

synchronous transfer mode

This is a proposed transport level technique used in a Broadband Integrated Services Digital Network (B-ISDN). Herein, time-division multiplexing and switching are both used across the user's network interface.

synchronous transmission

A means of sending data in which a clocking signal is used and the characters are separated by time intervals, rather than by start and stop bits as in asynchronous transmission. Synchronous transmission is faster than asynchronous because there is no need for a start bit and stop bit on each character; however, it is more expensive. Most computer terminals use asynchronous data transmission; some modems convert asynchronous signals into synchronous signals for very fast transmission.

SyQuest disk

A cartridge hard disk that is used with the SyQuest removable hard drives. SyQuest disks are available in several 5.25″ formats with up to 200 MB storage, or 3.5″ formats with up to 270 MB. The SyJet, a newer SyQuest drive, has cartridges with over 1 GB storage.

SyQuest drive

A removable hard disk drive which is connected to the computer via a SCSI interface. SyQuest drives, developed by SyQuest Technology, come in 3.5″ and 5.25″ sizes, with removable cartridges that can greatly increase the computer's storage. A newer drive from SyQuest is SyJet, a 1.+GB external SCSI drive.

SyQuest Technology, Inc.

A Fremont, California corporation that developed a line of removable hard disk drives called SyQuest drives, with removable cartridge hard disks.

sys admin

System administrator. The person in charge of a multiuser computer system. The system administrator designs the system and manages its use.

sysop

System operator. The operator of a local area network, bulletin board, or online service. The sysop may act as a mediator for online conferences or forums.

sysprog

Systems programmer. 1. A person who writes system programs, those programs which enable a computer system to function, as opposed to application programs. 2. A technical expert in a large corporation who oversees the computer systems and is responsible for the installation and integration of new hardware and software.

system administrator

The person in charge of a multiuser computer system, also called sys admin. The system administrator designs the system and manages its use.

system analyst

Also called systems analyst. A person who designs or modifies an information system to meet the requirements of its end user. System analysis includes investigating the program's feasibility and cost, producing documentation, and testing a prototype of the system at several stages of its design.

system board

The motherboard; the main printed circuit board that contains the central processing unit for the computer, memory, and sometimes printer ports or other devices.

system clock

The main clock that controls the timing within a computer by generating a series of pulses that are used to synchronize its circuits and operations.

system disk

A disk that contains the operating system, or enough of the operating system to boot the computer. It can be a hard disk, a floppy disk, a SyQuest disk, or a CD-ROM.

system enabler

A system update file for Macintosh that must be present to tell the System 7 operating system which model of Macintosh it is running.

System Folder

A folder on the Macintosh that contains the System, Finder, printer drivers, control panels, fonts, desk accessories, extensions, preferences, INITs, and other files that help to run the computer.

system integration

Assembling many components so they can work together as a system.

system level

On the level of the operating system or system programs.

system management

The management of computer systems in an enterprise, which may involve a system manager and system management software. System management includes analysis and design of systems, development and updating of software, elimination of redundancy, and management of networks, security, job scheduling, maintenance and repair.

system manager

A systems programmer who manages the technical aspects of systems development, which includes software analysis and design, program implementation and maintenance, and updates.

system memory

The memory the operating system uses.

system operator

The operator of a local area network, bulletin board, or online service, also called sysop. The sysop may act as a mediator for online conferences or forums.

system program

A program which is part of the system software used to control the computer and run applications. System programs include database managers, drivers, communications and messaging protocols, the basic input/output system, etc. Contrast with application program.

System Services Control Point

(SSCP). Software that manages all resources in a mainframe-based Systems Network Architecture (SNA) network.

system software

The software which controls the computer and runs applications. System programs include operating systems, database managers, drivers, communications and messaging protocols, basic input/output system, etc.

system time

The time of day according to a clock in the computer, which runs on a battery so it keeps time even when the computer is turned off. The system time is recorded when files are created or edited. The system time is also used for calendar and reminder programs, electronic mail schedules, and various other operations.

system unit

The main unit of a computer, that contains the central processing unit (CPU) and motherboard. It may have disk and diskette drives, ROM, RAM, and one or more input/output channels. Expansion units can be attached to give the computer added capabilities.

Systeme Internationale d'Unites

(SI). The international metric system.

Systems Administrators Guild

(SAGE). A special technical group of the USENIX Association, a body which focuses on research and innovation in UNIX and open systems.

systems analysis

The analysis of an information system with a view to designing or modifying it to meet the needs of the end user. Systems analysis includes investigating a program for feasibility and cost, creating documentation, and testing a prototype of the system at several stages of its design.

systems analysis definition

(SAD). The beginning step of systems analysis, in which the end user's requirements are defined in order to get an idea of what kind of system must be designed to meet those needs.

systems analyst

Also called system analyst. A person who designs or modifies an information system to meet the requirements of its end user. Systems analysis includes investigating the program's feasibility and cost, producing documentation, and testing a prototype of the system at several stages of its design.

Systems Application Architecture

(SAA). A set of interfaces, guidelines, and protocols developed by IBM to encourage the development of software that is consistent regardless of hardware or operating system. SAA governs user interfaces, communications protocols, programming languages, and procedure libraries.

systems development

The analysis and design of computer systems, including the development and implementation of applications.

systems integration

Assembling complete systems out of many components, and integrating them so all work together.

systems integrator

A company that takes components from more than one vendor and assembles complete computer systems for sale.

systems management

The management of computer systems in an enterprise, which may involve a systems manager and systems management software. Systems management includes analysis and design of systems, development and updating of software, elimination of redundancy, and management of networks, security, job scheduling, maintenance and repair.

Systems Network Architecture

(SNA). A networking protocol standard for IBM mainframes and IBM-compatible mainframes.

systems programmer

Abbreviated sysprog. 1. A person who writes system programs, those programs which enable a computer system to function, as opposed to application programs. 2. A technical expert in a large corporation who oversees the computer systems and is responsible for the installation and integration of new hardware and software.

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