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Computer, Telephony & Electronics
Industry Glossary


An acronym for Switched 56 Kbps Digital Service. A service provided by local exchange and interexchange carriers (LECs and IECs) that allow customers to use high-speed switched digital data capability without having to subscribe to private network services.


A temporary, usually very fast, drop in electrical voltage. It is usually associated with the supply voltage to the computer, not inside the computer. Sags are the opposite of spikes and are sometimes called brown downs when the sag is not momentary. They are very often damaging to computer equipment.


An acronym for Serial Access Memory. A SAM is a serial register built into a VRAM to enable it to transfer large quantities of data from the DRAM portion of the device to a graphics controller or frame buffer. A full SAM is 512K x 16; a half SAM is 256K x 16.


1. From its early beginning in 1946 as a leading provider of electrical books, Sams Publishing has established a long history of supplying technical minds with technical information. Today, with best-selling titles such as Sams Teach Yourself HTML 4 in 24 Hours and Red Hat Linux Unleashed, Sams Publishing (HTTP://WWW.SAMS.COM) is one of the largest and most successful computer book publishers in the world generating over 45 million in sales and 450 titles in print. They are now owned by McMillan Publishing, a giant in the publishing industry and heavy into computer technology publishing (HTTP://WWW.MCP.COM).
2. An industry term to identify a schematic diagram for anything electronic. Originally the Howard W. Sams Company, it is now Sams Technical Publisihing. See them at HTTP://WWW.SAMSWEBSITE.COM.


A leading manufacturer and supplier in all commercial electronics industries worldwide. They have several International manufacturing and operations locations. See them at HTTP://WWW.SAMSUNG.COM.


An acronym for Storage Area Network. A network, or usually, a section of an enterprise network, that is there only to store data for backup purposes or for data retrieval purposes. It can be in any configuration or topology.


1. An acronym for Service Advertising Protocol. A Novell NetWare protocol used to identify the services and addresses of servers attached to the network. The responses are used to update a table in the router known as the Server Information Table.
2. An acronym for Secondary Audio Program. An NTSC audio channel used for auxiliary transmission, such as foreign language broadcasting or teletext. Most current television devices have provisions for SAP.

satellite radio

A technology for streaming audio from satellites to stations on the Earth (or in the air) for reception. More information here.


An acronym for Single Board Computer. Generally a complete industrial or control computer on one board.


An acronym for Slow But Sure Death. A term used by hardware repair people that refers to the fact that computers are not in question as to IF they will crash and die; it is only a matter of when. The three lethal factors are heat, power that is not clean and cigarette smoke residue. The acronym applies to humans as well; everyone knows that. However the heat and power are not as critical as the loaded gun in the form of cigarettes.
Smoke in power supplies and on mainboards leaves a greasy, oily residue that is actually conductive. Once it begins to pick up dust, heat begins to build and a path allowing electricity to take the path of the least resistance happens. Shorts from smoke and dust residue are frequent and most always lethal to the computer.


A fraudulent scheme that is used to attempt to obtain money from a person via the Internet.


A drawing that shows the electronic configuration and values of all the circuits in an electronic device. It is not a pictorial layout or view. See SAMS. We also recommend and suggest that you visit an excellent site that has a great wealth of schematic information, a creation of the author of Internet Guide To Electronics, John Adams. It is well worth a visit.


A particular type of diode that is a fast switching silicon diode with a low forward voltage drop.

scientific notation

Scientific notation is used to express very large or very small numbers. A number in scientific notation is written as the product of a number (integer or decimal) and a power of 10. This number is always 1 or more and less than 10. For example, at the time of this writing, there are approximately 6,000,000,000 humans on earth. (See our World Population Estimate Calculator for an updated estimate!) This number could be written in scientific notation as 6x109. The number 6,000,000,000 is equivalent to 6*1,000,000,000. The number 1,000,000,000 is equivalent to 109 or 10*10*10*10*10*10*10*10*10. A number can be converted to scientific notation by increasing the power of ten by one for each place the decimal point is moved to the left. In our example, the decimal point was moved 9 places to the left to form a number more than 1 and less than 10. Scientific notation numbers may be written in different forms. The number 6x109 could also be written as 6e+9. The +9 indicates that the decimal point would be moved 9 places to the right to write the number in standard form. Check out our Scientific Notation To Decimal Converter and our Check out our Decimal To Scientific Notation Converter for more information.


An SCR is a unidirectional thyristor and a triac is bidirectional thyristor. A positive SCR gate signal turns that device on. The main SCR circuit is anode to cathode and is controlled by a positive gate voltage.


This is the process of taking an image of what is being displayed and making a "snapshot" of it at a given time. See our page on how to actually do a screencapture.

screen name

The name you use to represent yourself online, often known as a cyber identity. Your ISP account can have one or more different screen names. For more information on creating or deleting screen names, contact your ISP. Also see screenprint.


This is the process of printing an image of what is being displayed and making a printed "snapshot" of it at a given time. While it a wonderful tool, depending on the actual scree and printer, the process has some potential flaws. We suggest doing a screencapture and then printing that. See our page on how to actually do a screencapture.


See screencapture.

scroll bar

1. The name given to the vertical and horizontal Windows movement bars at the right side and bottom of windows that contain more data than will display in the parameters of the window.
2. The bar on the side or bottom of a window that allows the user to scroll up and down through the window's contents. Scroll bars have scroll arrows (AKA scroll bar directors) at either end and a scroll box (the scroll position indicator), all of which can be used to scroll around the window. Clicking on the scroll bar itself creates a very rapid scrolling effect, up or down, left or right, depending on where you click before or after the indicator, while clicking on the directional arrow causes the scrolling to take place only one increment at a time. Dragging the scroll position indicator allows the user to move in the fastest possible time.
3. SCROLL; an acronym for Adventure gamers, SCrawny trOLL.
4. A watering hole for scrolls.
5. A place where you can usually find scrolls hanging out, particularly late at night. See spacebar if looking for space cadets or a status bar if you are looking for something else.

scroll bar director

1. The up or down, left or right arrow at the ends of a scroll bar. See scroll bar for specific actions.
2. An executive scroll.


To cause disruption in a chat room by entering several lines of text faster than other members are able to type. Scrolling is a definite no-no as far as courtesy and in many cases is reason for an ISP to terminate your service.


An acronym for Small Computer Systems Interface. This is a particular protocol for the host motherboard, CPU and related devices to communicate with I/O devices such as disk drives, tape drives, removable storage drives, CD-ROMS, CD-RWs, DVDs, scanners and the like. This is pronounced "scuzzy". The technology has been around for several generations of advancement. All SCSI systems are still current technology, even the 8-bit systems; however the advancements are in multi-user DMA ability and speed of data transfer from device to actual user memory pool. SCSI was introduced in small scale in 1976 on CP/M systems that were considered high performance and has been the default drive interface for most apple systems since then. SCSI systems are more efficient than IDE or EIDE devices in how fast data gets from one place to another and how many devices can be addressed and utilized from the same controller. Virtually all SCSI controllers allow up to eight SCSI devices; some allow up to sixteen. While there have been in the past and there are at present numerous SCSI controller manufacturers, Adaptec is the technology leader and controls the market share of SCSI device controllers. Although SCSI systems can be and are often used as high performance work stations, they are most often used as network and Internet servers. SCSI is a parallel interface standard used by Apple Macintosh computers, PCs, and many UNIX systems for attaching peripheral devices to computers. Nearly all Apple Macintosh computers, excluding only the earliest Macs and the recent iMac, come with a SCSI port for attaching devices such as disk drives and printers. SCSI interfaces provide for faster data transmission rates (up to 80 megabytes per second) than standard serial and parallel ports. In addition, you can attach many devices to a single SCSI port, so that SCSI is really an I/O bus rather than simply an interface. Although SCSI is an ANSI standard, there are many variations of it, so two SCSI interfaces may be incompatible. For example, SCSI supports several types of connectors. While SCSI has been the standard interface for Macintosh, the iMac comes with IDE, a less expensive interface, in which the controller is integrated into the disk or CD-ROM drive. Other interfaces supported by PCs include enhanced IDE and ESDI for mass storage devices, and Centronics for printers. You can, however, attach SCSI devices to a PC by inserting a SCSI controller board in one of the expansion slots. Many high-end new PCs come with SCSI built in. Note, however, that the lack of a single SCSI standard means that some devices may not work with some SCSI boards. The following varieties of SCSI are currently implemented:

SCSI-1: Uses an 8-bit bus, and supports data rates of 4 MBps
SCSI-2: Same as SCSI-1, but uses a 50-pin connector instead of a 25-pin connector, and supports multiple devices. This is what most people mean when they refer to plain SCSI.
Wide SCSI: Uses a wider cable (168 cable lines to 68 pins) to support 16-bit transfers.
Fast SCSI: Uses an 8-bit bus, but doubles the clock rate to support data rates of 10 MBps.
Fast Wide SCSI: Uses a 16-bit bus and supports data rates of 20 MBps.
Ultra SCSI: Uses an 8-bit bus, and supports data rates of 20 MBps.
SCSI-3: Uses a 16-bit bus and supports data rates of 40 MBps. Also called Ultra Wide SCSI.
Ultra2 SCSI: Uses an 8-bit bus and supports data rates of 40 MBps.
Wide Ultra2 SCSI: Uses a 16-bit bus and supports data rates of 80 MBps.

Secure Digital or SD

This is a type of technology, formally known as Secure Digital, for mass storage devices in the form of a new type of memory media with a compact design, image storage capacity of up to 1GB, compatibility with different digital camera brands and MP3 devices, roughly the size of SmartMedia cards. SD is part of a generic category of media called Digital Flash Media (DFM).


1. An acronym for Synchronous Digital Hierarchy. SDH is the international standard for transmitting digital information over optical networks. It is a term used by ITU to refer to the ANSI standard, SONET.
2. An international standard for synchronous data transmission over fiber optic cables. The North American equivalent of SDH is SONET. SDH defines a standard rate of fiber optic transmission at 155.52 Mbps, which is referred to as STS-3 at the electrical level and STM-1 for SDH. STM-1 is equivalent to SONET's Optical Carrier (OC) levels -3.


An acronym for Software Development Kit. A Usually published and provided by a specific software company, such as Microsoft or Sun (JDK), so that developers get a wide and varied assortment of tools and libraries that will help them to develop programs that are based on that manufacturers software.




An acronym for Synchronous DRAM. A DRAM technology that uses a clock to synchronize signal input and output on a memory chip. The clock is coordinated with the CPU clock so the timing of the memory chips and the timing of the CPU are "in synch." Synchronous DRAM saves time in executing commands and transmitting data, thereby increasing the overall performance of the computer. SDRAM allows the CPU to access memory approximately 25 percent faster than EDO memory.


An acronym for Symmetric Digital Subscriber Line, a new technology that allows more data to be sent over existing copper telephone lines (POTS, plain old telephone service). The terms SDSL, SLDSL and just DSL are often used interchangeably. SDSL supports data rates up to 3 mbps. SDSL works by sending digital pulses in the high-frequency area of telephone wires. Since these high frequencies are not used by normal voice communications, SDSL can operate simultaneously with voice connections over the same wires. SDSL requires a special SDSL modem. SDSL is called symmetric because it supports the same data rates for upstream and downstream traffic. A similar technology that supports different data rates for upstream and downstream data is called asymmetric digital subscriber line (ADSL). ADSL is more popular in North America, whereas SDSL is being developed primarily in Europe. See XDSL, HDSL, ADSL, SLDSL and DSL. Each has some advantages, however all of the different forms of DSL are full time connections, as opposed to dial-up technology.


An acronym for Standard Definition TV, the conventional plain vanilla television technology. In contrast to SDTV, the more advanced capabilities are found in DTV, SDTV, EDTV, HDTV, PTV, RPTV, DVI, DLP, LCD, LCOS, plasma display, progressive scan, component video, S-Video, composite video, and others. Standard definition television is the digital television format that provides a video quality near the equivalent of DVD. SDTV and HDTV are the two designations of display formats for digital television (DTV) transmissions, which are standards as of 2004. HDTV provides a higher quality display, with a vertical resolution display from 720p to 1080i, or higher, and an aspect ratio (the width to height ratio of the screen) of 16:9, 16 inches wide for every 9 inches high. In contrast, SDTV has a range of lower resolutions and no defined aspect ratio. New television sets are either HDTV capable or SDTV capable, with receivers that can convert the signal to their native display format. Both SDTV and HDTV use the MPEG-2 file compression method with transmitted data. However, because a compressed SDTV digital signal is smaller than a compressed HDTV signal, broadcasters can transmit up to five SDTV programs simultaneously in lieu of just one HDTV program. This process is known as multicasting, a very attractive feature because television stations can receive additional revenue from the additional advertising these extra programs provide. On analog television broadcast systems, only one program at a time can be transmitted.


A clock timer chip, made originally by Signetics. See 555.


An industry leader in the disk drive and storage industry. Visit them at HTTP://WWW.SEAGATE.COM.


1. The process of attempting to acquire information or data. In the case of the Internet, it is usually done with a search engine.
2. The result of the use of a search engine.

search engine

A database, or index that can be queried to help you find information on the World Wide Web. For example, WebCrawler, Alta Vista and Yahoo are some of many. The King of the Hill and undisputed champ of the contenders is Google, maintaining that position from 2001 through 2006. While often directories, guides and listing services are often called search engines, they in fact do maintain publicly searchable databases that can be searched. For that reason, we generally categorize them with search engines. However, the primary difference is that they do NOT go out to the Internet and search for pages to put in the database. The pages must be brought to them. There are also niche, or specialty search engines, that only search for one item, one business, one vertical market, thing or service. As a general rule, these are most often better at what they do than a general search engine. There are also local search engines that only search and find things on one site.

There are roughly 2400 known, reasonably good or better, search engines, guides and directories; about 300 are considered extremely useful while about 20 are major and get the lion's share of use. Most do one sort or search better than others. In order to do business on the Internet, people (customers) must be able to find you. That process is accomplished through search engines. The task of "publishing" your site to many search engines is in itself, a profession. The ability to do that well is the difference between a fair online store and a very good one. Check out CSG's listing of search engines, use our featured meta-search engine or use our local site search.


1. A unit of measure for time. One second is 1/60th of a minute.
2. A unit of measure of angles equivalent of 1/60th of a minute, which is 1/60th of a degree.

secondary memory

Secondary memory (or secondary storage) is the slowest and cheapest form of memory. Technically, it is considered data storage but if it is accessible to primary memory, it is in fact memory. It cannot be processed directly by the CPU. It must first be copied into primary memory (also known as DOS). Secondary memory devices include magnetic disks like hard drives and floppy disks; optical disks such as CDs and CDROMs; and magnetic tapes, which were the first forms of secondary memory. This process has been around for many years. Mainframes and mini-computers of the 60's used to write temporary "files" to the system hard disk, that contained what each user was doing when his chunk of CPU time was done. The whole process was called a cycle. When it was his time for CPU attention again, the temporary file would be read back into memory and acted on. It was initiated when real memory was too expensive to have much of and in fact, CPUs could only address small amounts of it anyway. Then the process was called paging. The term was later used on Z80 machines to address more than one 64KB block of actual RAM. Since all 8 bit processors are limited to 64KB of addressable memory, this was a "trick" process to keep some memory waiting, live and on hold, while fetching some more. Since the 8 bit systems could address 65,536 bytes directly, each page was that less 128 bytes for housekeeping. The equivalent in today's memory world is virtual memory, swapping (you remember the infamous swap file) or demand paging. All the processes are used by the somewhat questionable algorithm of Windows to do what it needs to do with memory and the hard disk. The process is often confused with caching but in reality, it is not the same.


A magnetic section of a disk or diskette that is marked by magnetic boundaries and designated by a computer readable numeric ID. A sector contains a given amount of data in bytes, usually 512 though 128, 256 and 1024 byte sectors are also used. A sector is inside of a track, which is within a cylinder. The computer's file allocation table (FAT) keeps track of what data is in what sector. In the early days of floppy diskettes, there was an alternative to electronic marked sectors. That system was called hard sectoring and proved to be very unpopular. There were actual index holes punched in the media to mark the beginning and ending points of sectors. The current system is frequently referred to by veteran IP staff as soft sectoring.


Ensuring that private information remains private in an atmosphere where all other information is free. Security also means that viruses are prevented from infecting people's systems.


SeniorNet is a non-profit organization for older adults interested in using computers. SeniorNet members are 55 or older and have an interest in learning about and with computers.


A segment is a physically or logically distinct section of a network. Segments are used to isolate network traffic, and often have specific limitations on their physical size and number of hosts and other physical connections.

self refresh

1. A memory technology that enables DRAM to refresh on its own-independent of the CPU or external refresh circuitry. This technology is built into the DRAM chip itself and reduces power consumption dramatically. It is commonly used in notebook and laptop computers. See refresh.
2. Getting your own Pepsi.


A material that is neither a good conductor of electricity (like copper) nor a good insulator (like rubber). The most common semiconductor materials are silicon and germanium. These materials are then doped (coated) to create an excess or lack of electrons. Computer chips, both for CPU and memory, are composed of semiconductor materials. Semiconductors make it possible to miniaturize electronic components, such as transistors. Not only does miniaturization mean that the components take up less space, it also means that they are faster, require less energy, and emit far less heat.

sequential access

Refers to reading or writing data records in sequential order, that is, one record after the other. To read record 10, for example, you would first need to read records 1 through 9. This differs from random access, in which you can read and write records in any order. Some programming languages and operating systems distinguish between sequential access data files and random access data files, allowing you to choose between the two types. Sequential access files are faster if you always access records in the same order. Random access files are faster if you need to read or write records in a random order. Devices can also be classified as sequential access or random access. For example, a tape drive is a sequential access device because to get to point X on the tape, the drive needs to pass through points A through W. A disk drive, on the other hand, is a random access device because the drive can access any point on the disk without passing through all intervening points. There is a method that is considered hybrid, ISAM. It is somewhat the best of both worlds.


In computer communications, serial refers to one by one. Serial data transfer is defined as transmitting data one bit at a time, in a stream across one line, often, as it may be, a very slow stream. The opposite of serial is parallel, in which several bits are transmitted concurrently, across several lines.
Parallel transfers and communications are a factor of how many lines are available (x) times faster than serial communications. The newest technology in serial connections is USB, the Universal Serial Bus. See our detailed explanation of serial communications.

Serial Line Internet Protocol - SLIP



In electronics, two components can be connected together in two different ways, series and
parallel. Each component has two different ends or poles. They can be positive and negative but may not be. For identification, they are known as Alpha and Beta. While the nomenclature is not exactly original, it serves the purpose. If similar components, such as a resistor and another resistor, or a capacitor and another capacitor, are in series in a circuit, the alpha pole of one is connected to the beta pole of the other, directly, while the other alpha and other beta poles do NOT connect. See our Series Resistance Calculator and our Series Capacitance Calculator to resolve values for either resistance or capacitance.


A hardware device that is the central point, or one of them, for a network. There are many servers on the Internet. Files for each Internet site are stored and executed on the server. While there are many different types of servers, they share the common job of providing access to files and services. Some servers only handle mail or only files, while others do more than one job. They are attached to the network by an interface that may be a true network or by telephone line connection.

Server Gated Cryptology - SGC

SGC is a technology for another level of transaction and operation security on the Internet. It is associated with online banking. It is a product of Microsoft (you expected someone else?). Microsoft can be accessed through HTTP://WWW.MICROSOFT.COM or at many banks throughout the world.

Service Release 1 or SR1

SR1 is the name first given to a group of fixes and patches to Microsoft's Office '97 Suite of programs (and subsequent releases of Office). In a typically confusing manner, Microsoft had two SR1 patches. The first added some additional problems to the Office 97 troubles. The second relieves all of them they say. Get all the details and the patch you need. If you installed SR1 earlier in the year, you need to reinstall per Microsoft's instructions. The term has evolved now to SPx, standing for service patch 1, 2 or whatever number is next. Most companies follow this guideline now. All SPs of a higher number cover the SPs of a lower number.

Service Release 2 or SR2

SR2 is the name given to a second generation group of fixes and patches to Microsoft's Office '97 Suite of programs and subsequent releases of Office. In a typically confusing manner, Microsoft has two SR2 patches, just as did SR1. (You think they would have learned...) The first did not install in all configurations of the Office 97 installation on some systems. The second corrects those problems they say. (Who is THEY anyway?) Get all the details and the patch you need. If you installed SR2 earlier and had problems, you need to reinstall per Microsoft's instructions. It requires SR1 be in place or Office '97 to be at a level of SR1.

session layer

Layer 5 of the OSI reference model. This layer establishes, manages, and terminates sessions between applications and manages data exchange between presentation layer entities. Corresponds to the data flow control layer of the SNA model. See also application layer, LLC, MAC, network layer, physical layer, PQ, presentation layer layer and transport layer.


An acronym for a long running government and private project. We were involved with it early on as a function of our operations with NASA. SETI (the Search for ExtraTerrestrial Intelligence) is a scientific effort to discover intelligent life elsewhere in the universe, primarily by attempting to discover radio signals that indicate intelligence. Cornell astronomer Frank Drake is credited with being the first to "listen" for intelligent signals with a radio telescope in 1960. Although NASA has funded some study in the past, current efforts are privately funded, in part by Arthur C. Clarke, Microsoft co-founder Paul Allen, Intel founder Gordon Moore, and Hewlett-Packard (HP) co-founders David Packard and William Hewlett. The SETI Institute's Project Phoenix is using computers to search about 1,000 stars within 200 light-years of our solar system for radio signals beamed toward us or any other location. Project Phoenix's 140-foot radio telescope in Green Bank, West Virginia aims at one star at a time while astronomer-monitored computers search each 1,000 band from 1,000 to 3,000 MHz for a signal limited to a narrowband range. Scientists believe that a signal focused within a narrow frequency band would suggest an intelligent source.
About two-thirds of the first 1,000 stars have been scanned or searched with no success yet reported. There are, however, over 400 billion stars in our own galaxy so the study may last quite a long time. The directors of the project are soliciting volunteers to help analyze the radio telescope data at their home computers.

settop box

Telephony slang term describing a terminating unit. A transmission/reception device that acts as an interface typically to a television or other video output display device. In addition to ADSL, SDSL, HDSL, and VDSL interfaces, settop units are increasingly modular and other interfaces can include Ethernet, MMDS, coaxial cable, V.34 modem, and ISDN, among others.


An acronym for Structured Graphics Format. An application of the eXtensible Markup Language, (XML), that is used to describe a Web site so that its pages and content can be displayed and accessed in a structured, usually tabular form. Using SGF, a Web site is rendered as a structured graph, which is a set of nodes and links that enable a browser to conveniently and intelligently interact with the site. A typical use of an SGF file is to describe a site to a browser in the form of a site map, which is created dynamically when requested by the user. If the structure of the site changes, the site map seen by a browser will change accordingly, without a human programmer having to intervene and write new HTML code. Typically, the user can also search on keywords, phrases, or topics. For SGF to be effectively used, the browser must use another client application, such as SFViewer and SGMapper. The client application creates the graphical interface that allows the user to navigate the site according to selected criteria. The idea is somewhat similar to the original concept that Microsoft had for ASP, Active Server Pages.


Short for Silicon Graphics Incorporated, a company based in Mountain View, California that provides computer hardware and software. SGI was founded by Dr. James Clark in 1982 and had its initial public offering in 1986. It is best known for products used to develop computer graphics such as those used to create special effects and animation in motion pictures. The company has over 10,000 employees world-wide and had sales of $2.9 billion in 1996. SGI formed Silicon Studio in 1994 to serve the interactive digital media market. The company merged with MIPS Computer Systems in 1992, Alias Research and Wavefront Technologies in 1995, and Cray Research in 1996 (See our favorite computer...). SGI provides a wide range of hardware and software products that include high-performance workstations and servers to meet the needs of those developing complex computer graphics or manipulating video images. New products include World Wide Web authoring tools and servers. Visit the website at HTTP://WWW.SGI.COM.


Standard Generalized Markup Language is what HTML is based on. This is an ISO standard.


A leading manufacturer and supplier in all commercial electronics industries worldwide. They have several International manufacturing and operations locations. See them at HTTP://WWW.SHARP-WORLD.COM.


A leading designer, manufacturer and supplier of commercial networking products. They are now owned by Intel Corporation. See them at HTTP://WWW.SHIVA.COM.


A 'try before you buy' program. If you decide to keep and use the program beyond the trial period (usually 10 to 30 days) you are requested to pay a fee to the author. See freeware.


A particular type of diode that is a thyristor that switches once its breakover voltage is reached. It is also known as a four layer diode.


TYPING IN ALL CAPITAL LETTERS IS CONSIDERED SHOUTING IN ONLINE COMMUNICATIONS OR IN CERTAIN E-MAIL DOCUMENTS. Avoid this unless you really mean to shout. If you really mean to shout, do it out loud: it feels much better. If the need arises, you can even use RTF or HTML in some E-Mail, and use really large fonts! Oh Joy!


A CD-ROM title that contains pre-existing material, usually taken from other media, that has been shoveled in by the developers in order to fill the 600 MB of disk space.


An extension to the HTTP protocol to support sending data securely over the World Wide Web. Not all Web browsers and servers support S-HTTP. Another technology for transmitting secure communications over the World Wide Web, Secure Sockets Layer (SSL), is more prevalent. However, SSL and S-HTTP have very different designs and goals so it is possible to use the two protocols together. Whereas SSL is designed to establish a secure connection between two computers, S-HTTP is designed to send individual messages securely. Both protocols have been submitted to the Internet Engineering Task Force (IETF) for approval as a standard. S-HTTP was developed by Enterprise Integration Technologies (EIT), which was acquired by Verifone, Inc. in 1995.


A leading manufacturer and supplier in all commercial electronics industries worldwide. They have several International manufacturing and operations locations. See them at HTTP://WWW.SIEMENS.COM.


Abbreviation for Special Interest Group. SIGs were first prominent in the days of public domain software, now as groups with special related interests. See freeware.


Short for signature, a group of lines attached to the end of a message that identifies the author and often includes additional information such as contact information, organizational affiliation, or a favorite quote. Sigs can also include ASCII art. Netiquette suggests limiting sigs to a maximum of four or five lines.


1. A generated electrical impulse that is a change in voltage to trigger an event.
2. An generated analog or audio tone to cause something to happen.
3. A waveform on a scope.


The process of sending a transmission over a physical medium for purposes of communication.

Silicon Alley

The area of Manhattan where many Internet development companies are located.

Silicon Valley

The geographic center of the computer industry. Includes most of Santa Clara county and part of San Mateo county in California. Those in the industry feel it is the capitol of the world.

sim (simming) or simulations

1. Short for simulation or simulator. Sims are role playing games that allow players to join in easily. The sim game is based in a virtual world where the players create a character and act as the character would in the given situations. Many Sims are based on well known TV shows or familiar stories. This sort of role playing initiated the term artificial intelligence on early computers.
2. A telephony acronym for Subscriber Identity Module. That is a card that contains subscriber identifying data about a user that can be used to gain access to a network. Frequently used in GSM phones. This is often called a smart card.


This is a type of memory and an acronym for Single Inline Memory Module; it is hardware inside the computer. It comes in various sizes and configurations to suit the needs of the system and user. A printed circuit board with gold or tin/lead contacts and memory devices. A SIMM plugs into a computer's memory expansion socket. SIMMs offer two main advantages: ease of installation and minimal consumption of horizontal surface area. A vertically mounted SIMM requires only a fraction of the space required by horizontally mounted DRAM. A SIMM may have as few as 30 or as many as 200 pins. On a SIMM, the metal leads on either side of the board are electrically "tied together." See DIMMS.


An acronym for Sunshine Internet Radio. This is a "narrowcast" on a very limited budget; a one man operation with Tony West living the DJ dream! Tune in and listen please... on Destiny Radio / Pirate Radio Network simultaneously. You don't have to be ABC, NBC or just big in general to get your point across.


A spectacular technology of satellite radio; it is a paid service, however, well worth the small charge in our opinion, costing slightly more than the competing technology, XM Radio. Each unit has an identity module that is registered with the service, once activated, it is usable 24 hours a day, anywhere in the country, perhaps on the continent. They began actual operation on February 14, 2002, offering 100 channels or more of music and entertainment.

The three Sirius satellites (and a spare ready for launch if needed, broadcast on designated frequencies between 2,320.00 and 2,332.50 MHz, in the S band (current S Band users here). The first, Sirius Radio 1, known internationally as 2000 035A, was launched June 30, 2000, from from Baikonur Cosmodrome, Kazakstan, the Russian Federation, pad 24 at 3:08:47 p.m. PDT (2208:47 UTC). Sirius Radio 2 was launched on September 5, 2000, while Sirius Radio 3 was launched on November 30, 2000; both were also launched from from from Baikonur Cosmodrome, Kazakstan. The Sirius satellites, manufactured by Space Systems/Loral, HTTP://WWW.SSLORAL.COM of Palo Alto, CA, operate in planned non-geostationary, elliptical orbits ranging from a perigee (closest to the Earth) of 23,975 km (12,950 nautical miles) to an apogee of 46,983 km (25,375 nautical miles), inclined at 63.4 degrees, to ensure signal elevation angles of 60 to 90 degrees. Each satellite is available for digital broadcast about 16 hours a day due to the orbit; because there are 3, one is always in position but, as does XM Radio, Sirius uses ground based repeaters also. Check this new innovation out on the web at HTTP://WWW.SIRIUS.COM (Please see our commentary as to why this is NOT a link to Sirius...) for more details and programming information. Sirius has 22 automotive partners and 12 manufacturing partners as of spring 2005.

The Sirius Radio satellites are not to be confused with those of the European Swedish Space Corporation and SES GLOBAL organizations, HTTP://WWW.NSAB-SIRIUS.COM, each owning 50% in NSAB. Swedish Space Corporation (SSC) is a state-owned limited company with operations in Stockholm and Kiruna, Sweden. Those satellites are Sirius W, Sirius 2 and Sirius 3. In May of 2003, the Sirius W bird completed its planned mission and was directed to what is known as a graveyard orbit.


A designation for a group of portable and notebook computers and computing devices that accept input from a pointing device such as an electronic pen rather than from a keyboard. (Touch screen technology is also in the picture.) Slate units are particularly useful in situations where keyboards are undesirable or are not practical to use. Technology in this field is moving in two diverse paths. In the first, slates can decipher clearly written block letters (scanner technology with a free form font) and translate them into their ASCII equivalents. To date, however, they cannot handle script, although the technology of handwriting recognition is progressing rapidly. In order to accommodate that, the second direction is that of a psuedo-scanned image, handled entirely as a graphic image. Each has some benefit; each has some draw back. Both technologies are making good progress. It is my contention that both will evolve into separate products.


SLDRAM is a "joint effort" DRAM that may be the closest speed competitor with Rambus. Development is coordinated through a consortium of twelve DRAM manufactures and system companies. SLDRAM is an enhanced and faster line extension of SDRAM architecture that extends the current four-bank design to 16 banks. SLDRAM is currently in the early production stage since late 1999.


Acronym for Single Line Digital Subscriber Line, a new technology that allows more data to be sent over existing copper telephone lines (POTS). This is frequently used in place of the term SDSL or often termed just DSL. SDSL supports data rates up to 3 mbps. SDSL works by sending digital pulses in the high-frequency area of telephone wires. Since these high frequencies are not used by normal voice communications, SDSL can operate simultaneously with voice connections over the same wires. SDSL requires a special SDSL modem. SDSL is called symmetric because it supports the same data rates for upstream and downstream traffic. A similar technology that supports different data rates for upstream and downstream data is called asymmetric digital subscriber line (ADSL). ADSL is more popular in North America, whereas SDSL is being developed primarily in Europe. See XDSL, HDSL, ADSL, SDSL and DSL.

slide rule

The grandmother of all computers... The slide rule is a hand held instrument (requiring no batteries or electricity) for math calculations. It is actually two scales, side by side, that slide against each other. The scales are marked identically but are usually multiple, each scale for a different operation. An example might be two rulers (yard sticks or meter sticks), side by side. In fact, engineers that carried them during the 50's, 60's and a few into the 70's, lovingly called them slip-sticks. While they did not do operations in MIPS as today's computers do, they were very adequate in accurate calculations, to at least 2 decimal places, and very fast. Most people that know how to use a slide rule can still arrive at an answer (to 2 or 3 decimal places) faster than someone skilled at a calculator. Slide rule use also taught the beyond actual calculation principles of math, such as how to use a formula and how to estimate, rather than expecting a calculator to return a "correct answer" but not really having an idea if the answer returned was even close to correct. See this site to use a Java online version of a slide rule. See this site for information on other pre-calculator calculating devices.


Serial Line Internet Protocol, one of two standard methods of connecting to the Internet, often known also as SLP. With a SLIP account, you can connect to your ISP over the Internet. You can also use your current ISP account as a SLIP connection to the Internet. As the name implies, it is a protocol. A protocol used by TCP/IP routers and PCs to send packets over dial-up and leased-line connections. SLIP has been pretty much replaced by PPP. Sometimes called Single Line Internet Protocol or Single Line Protocol.


In computers, a slot, or expansion slot, is an engineered technique for adding capability to a computer in the form of connection pinhole type contact points (typically, in the range of 16 to 64 closely spaced holes), and a place to fit an expansion card containing the circuitry that provides some specialized capability, such as video acceleration, sound, or disk drive control. Slots are connected directly to the BUS.


An acronym for Single Line Telephone. A telephony slang term for the barest of hardware capability.

SmartMedia or SM

A media storage and transfer technology primarily for digital cameras; SM is part of a generic category of media called Digital Flash Media (DFM). As of late 2001, this technology is not being updated and has faded in comparison to other technologies. Physically smaller than a book of matches and about as thick as a credit card. SmartMedia (SM) cards have no controller, they are simply memory that has been laminated on a plastic card. The controller has to be built into the camera and this causes incompatibilities with cameras made before 2001 and the most recent, higher capacity 64MB and 128MB size cards. Fuji and Olympus cameras were the most active manufacturers to use this technology but they, like many others have moved to x D technology.


A smartphone is a cellular phone with additional capabilities, like those that might be thought of as being on a computer or a personal digital assistant (PDA). With the cell industry being so competitive and so technology driven, there is no one smartphone definition that all companies agree on. A smartphone can make cell calls, organize contacts, send and receive text messages, have connectivity to computers, networks and other devices, run applications and programs (apps), give GPS instructions, send GPS data, take pictures, send and receive E-Mail, connect to the Internet, with wireless and wired capability. All smartphones do NOT do all of those but a few do all, and most of them do most of those tasks. All smartphones could be called computers by the pure definition of a computer, but few computers are smartphones. ALL smartphones have an operating system, as do computers. Most are on proprietary OS software but a few run special versions of known software such as Windows, Google's Android and Linux. Examples of proprietary OS software are Apple's iOS for the iPhone, Blackberry and Palm. Some smartphones have both touchscreens and keyboards (ALL of them offer QWERTY KBs or simulations), or one or the other. All smartphones are 2G netwoprk compatible, though very few actually operate on 2G any longer. Most smartphones are 3G data network compatible and a few are 4G compatible, though at the time of this update in late 2010, only Sprint has 4G networks up and running in a few areas. Many vendors and many smartphones offer compatibility to WiFi.


Acronym for Server Message Block Protocol. This architecture provides a method for client applications in a computer to read and write to files on and to request services from server programs in a computer network, local or distant. It can be used over the Internet on top of its TCP/IP protocol or on top of other network protocols such as Internetwork Packet eXchange (IPX) and NetBEUI. Using the SMB protocol, any application (or the user of an application) can access files at a remote server as well as other resources that are eligible network devices, including printers, scanners, copiers, FAXs, mailboxes, and named pipes. Thus, assuming adequate security permissions allow, a client application can read, create, and update files on the remote server. It can also communicate with any server's programs that talk to and understand an SMB client request. Microsoft's WFWG, W95, W98, WME, WNT and Windows 2000 all include client and server SMB protocol support. To provide similar capabilities on UNIX systems, a shareware program (as well as some public domain offerings of very limited capability), Samba, is available and somewhat supported. The SMB protocol originated at Microsoft (what didn't?) and has evolved to a seasoned protocol. Based on client and server agreements during negotiation while beginning a communications session, the two may implement different sets of protocol variations. In an effort to establish firm foundations for this protocol, Microsoft has offered an open public domain version of SMBP for the Internet to the Internet Engineering Task Force (IETF). It has been dubbed the Common Internet File System (Common Internet File System). This new protocol provides more flexibility than existing Internet applications such as the very seasoned File Transfer Protocol (FTP). CIFS is targeted as a beneficial attachment to the Internet's HyperText Transfer Protocol (HTTP) for Web browsing.


An acronym for Synchronized Multimedia Integration Language. This is a new avenue supported in Microsoft's IE5.5 browser. It is fully implemented as is CSS and DHTML.


:) This is one example of a Smiley (or Emoticon), the online means of facial expressions and gestures. Tip your head to the left and you will see the two eyes and smiling mouth. Please be aware that you will look exceptionally "strange" while tipping your head to view this.


1. An acronym for Symmetric MultiProcessing, a computer architecture that provides fast performance by making multiple CPUs available to complete individual processes simultaneously (multiprocessing). Unlike asymmetrical processing, any idle processor can be assigned any task, and additional CPUs can be added to improve performance and handle increased loads. A variety of specialized operating systems and hardware arrangements are available to support SMP. Specific applications can benefit from SMP if the code allows multithreading. SMP uses a single operating system and shares common memory and disk input/output resources; 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. Both UNIX and Windows NT support SMP. See AMP.
2. Acronym for Simple Management Protocol, another name for SNMP2. SNMP2 is an enhanced version of the Simple Network Management Protocol (SNMP) with features required to support larger networks operating at high data transmission rates. SNMP2 also supports multiple network management workstations organized in a hierarchical fashion.


An acronym (short for, pun intended) Short Message Service is the transmission of short text messages to and from a mobile phone, some pagers, Fax machine and/or IP address. Contrary to popular belief, this is NOT a chat room for people built close to the ground. Messages must be no longer than 160 alpha-numeric characters and contain no images or graphics. This allows low memory and display capable devices to view text intelligently. Once a message is sent, it is received by a Short Message Service Center, which must then get it via some means of distribution, to the appropriate mobile device. To do this, the SMSC sends a SMS Request to the home location register (HLR, roughly the equivalent of a DNS server on the Internet) to find the roaming customer. Once the HLR receives the request, it will respond to the SMSC with the subscriber's status: 1) inactive or active 2) where subscriber is roaming. With some (creative) liberty taken, the process is something like this.
SMSC: Hey AT&T, is Bill ( in the local area?
HLR: Just a minute and I'll check...
HLR: Well, he's not available but he was in the zone 2 of Northern California for some reason on his last usage a short time ago. Would you like me to do something for you?
SMSC: Just a minute while I think about that.
If the response is "inactive", then the SMSC will hold onto the message for a period of time. When the subscriber accesses his device, the HLR sends a SMS Notification to the SMSC, and the SMSC will attempt delivery.
(Our attempt continues...)
SMSC: Would you give him this message when you hear from him?
HLR: OK, I'll just hold it until he shows up again. See you later.
(After Bill turns on his super-duper cellular phone, the HLR sees that he is there.)
HLR: Hello Bill. Nice to see you are back with us. Here is a little 103 character message for you. Toodles...
(All of this is done in binary and ASCII and with no graphical intonations or voice conversation.) The SMSC transfers the message in a Short Message Delivery Point to Point format to the serving system. The system pages the device, and if it responds, the message gets delivered.
Bill: I got it!
The SMSC receives verification that the message was received by the end user, then categorizes the message as "sent" and will not attempt to send again. (Another tough day at the office!) The number of mobile and cellular phone users expects to reach 500 million worldwide by 2003, and with the help of SMS, 75 percent of all cellular phones will be Internet enabled through SMS or other technologies still emerging. You can send a short message via the CSGNetwork Message Transmitter, or here at the MTN SMS site!


Acronym for Short Message Service Center. (Usually located in a small, ground floor building with a low roof.) See SMS.


Short for Simple Mail Transfer Protocol, a protocol for sending E-Mail messages between servers. Most E-Mail systems that send mail over the Internet use SMTP to send messages from one server to another; the messages can then be retrieved with an E-Mail client using either POP or IMAP. In addition, SMTP is generally used to send messages from a mail client to a mail server. This is why you need to specify both the POP or IMAP server and the SMTP server when you configure your E-Mail application. SMTP is also thought of as Send Mail Transfer Protocol since the receive protocol has evolved into POP3.


See Systems Network Architecture.

snail mail

Regular postal mail from the USPS, as opposed to E-Mail. The term is honest, truthful and derogatory when implying postal mail's slowness relative to E-Mail. See what regular mail has become at the new USPS site. Also see Zip Code.


The transfer of electronic information by physically carrying disks, tape, or some other media from one machine to another. Used still, ironically.


A rude or malicious user who disrupts chat rooms or message boards. Usually, a "wannabe" hacker but with less intelligence or ability.


The process of listening to network traffic that you are not authorized to receive, a sniffer is a special software package that is capable of intercepting all traffic on a circuit, recording it for later analysis or searching for keywords and recording only specific sessions.


An acronym for Simple Network Management Protocol, a set of protocols for managing complex networks. The first versions of SNMP were developed in the early 80s. SNMP works by sending messages, called protocol data units (PDUs), to different parts of a network. SNMP-compliant devices, called agents, store data about themselves in Management Information Bases (MIBs) and return this data to the SNMP requesters. SNMP 1 reports only whether a device is functioning properly. The industry has attempted to define a new set of protocols called SNMP 2 that would provide additional information, but the standardization efforts have not been successful. Instead, network managers have turned to a related technology called RMON that provides more detailed information about network usage.


An industry acronym for Simple Object Access Protocol; provides a way for applications to communicate with each other over the Internet, independent of platform. Unlike DCOM's IIOP, SOAP adds a DOM onto HTTP associated (port 80) in order to penetrate server firewalls, which are usually configured to accept port 80 and port 21 (FTP) requests. SOAP technology relies on XML to define the format of the information and then adds the necessary HTTP headers to send it. SOAP was jointly developed by Microsoft, DevelopMentor, and Userland Software and has been proposed to the Internet Engineering Task Force (IETF) as a standard.


A protocol for handling TCP traffic through a proxy server, usually but not always to the Internet. It can be used with virtually any TCP driven application, including Web browsers and FTP clients. The purpose of SOCKS is protection. It provides a simple firewall because it checks incoming and outgoing packets and hides the IP addresses of client applications. It has the ability to not only mask or cloak them, but to translate them to something else if needed. There are two main versions of SOCKS, V4 and V5. V5 adds an authentication mechanism for additional security. There are many freeware and shareware implementations of both versions. One of the most common V5 implementations is SOCKS5, an adaptation developed by once powerful but now floundering NEC. SOCKS was recently accepted as an IETF standard and is documented in RFC 1928, 1929 and 1961.


A generic name for computer applications that allow and enable voice over IP operations on a network. This is crossover technology between the computer industry and the telephone industry. In other words, it is a program that emulates the use of a computer desktop phone image to place and receive emulated telephone calls that travel via the IP portion of a LAN, Intranet or Internet network. While there are several contenders in the market, the leader in the infancy of the market is Cisco. Check out the Cisco IP SoftPhone.


A collection of files that allow a computer to perform a certain task. The common tern is program. Software is associated with systems, networks, applications and is actually the working part of a ROM.

software library

Software libraries are home to collections of programs, graphics, and other files related to the specific forum the library is located in. For a complete listing of files available on your ISP's service, go to your files available listing.


1. Acronym for Small Office, Home Office.
2. A purist's pinball machine; a classic for nerds. Made famous by pinball wizards. See "Hair" and the rock opera, Tommy. Looking in the mirror, I have not seen it in years!

solid state

A term that literally means no moving parts, such as a transistor rather than a mechanical switch. Semiconductor devices are thought of as solid state. Many people incorrectly associate the term digital with solid state. That however, is incorrect. Analog is the opposite of digital and though they are often made with solid state devices, many analog devices are NOT digital.


An acronym for Synchronous Optical NETwork. SONET is the set of standards for transmitting digital information over optical networks. SONET was proposed by Bellcore in the middle 1980s and is now an ANSI standard. Fiber optic transmission standardized rates under the SONET guideline range from 51.84 Mbps (about the equivalent of a T-3) to 13.22 Gbps (roughly 25 times the bandwidth). It defines a physical interface, optical line rates known as Optical Carrier (OC) signals, frame formats and a OAM&P (Operations, Administration, Maintenance and Provisioning) protocol. The base rate is known as OC-1 and runs at 51.84 Mbps. Higher rates are a multiple of this such that OC-12 is equal to 622 Mbps (12 times 51.84 Mbps). See bandwidth. You can also look at the ANSI structure at HTTP://WWW.ANSI.ORG. The international equivalent of SONET, standardized by the ITU, is called SDH.


A leading manufacturer and supplier in all commercial electronics industries worldwide. They have several International manufacturing and operations locations. See them at HTTP://WWW.SONY.COM.


1. (v.) To categorize; to set apart various items into groups with similar characteristics.
2. (n.) A group of items with similar characteristics. For example, a sort of cheese.
3. A processing run on larger system computers. "I have a sort running."


The acronym for Service Patch, a term software companies use to denote a particular software fix. It is usually followed by a number such as SP1234.


1. The bar key, usually the largest in the keyboard, normally at the bottom of a standard computer keyboard. Usually used to insert spaces (ASCII 32) into text or as one of several possible, typical, keys when instructed to "hit any key to continue".
2. Where space cadets hang out.


A whimsical term for the unnecessary posting of messages or E-Mail. Posting a message that says "Me too!" is an example of this. Because of the meat it is named after, I term it canned garbage. Because there is a limited amount of bandwidth on the Internet, people who spam are held in contempt. Do something about it? Yes! See our links to assistance from the FTC and others...


A program that automatically fetches Web pages. Spiders are used to feed pages to search engines. It's called a spider because it crawls over the Web. Another term for these programs is WebCrawler. Because most Web pages contain links to other pages, a spider can start almost anywhere. As soon as it sees a link to another page, it goes off and fetches it. Large search engines, like Alta Vista, have many spiders working in parallel. Another term for spider is robot. See bot.


A temporary, usually very fast, increase in electrical voltage. It is usually associated with the supply voltage to the computer, not inside the computer. Spikes are the opposite of sags and are sometimes called bright lights when the spike is not momentary. They are very often damaging to computer equipment.


An acronym for Simple Programmable Logic Device, or Simple PLD. SPLDs are the smallest and consequently the least-expensive form of programmable logic. They include PALs, PLAs, FPLAs and are often just called PLDs. The other, more powerful form of PLD is a CPLD. An SPLD is typically comprised of four to 22 macrocells and can typically replace a few 7400-series TTL devices. Each of the macrocells is typically fully connected to the others in the device. Most SPLDs use either fuses or non-volatile memory cells such as EPROM, EEPROM, or FLASH to define the functionality.


The Splitter is a separate physical device that requires a skilled technician to install. The original ADSL standard, T1.413 incorporates a POTS Splitter in both the remote terminal and the central office. The splitter is designed to separate the voice band from the DSL spectrum. The idea is to protect both signals from interfering with one another. The issue of where the POTS Splitter belongs in both locations has been widely debated and is yet satisfactorily resolved. G.Lite eliminates the need for a POTS splitter, hence the term splitterless. It is designed to be implemented on a modem chipset with a PC. PCs that today provide 32Kbps and maybe 56Kbps will be capable of hundreds of kilobits using DSL-Lite. At a home a PC user simply plugs the DSL-Lite modem into the phone jack. This simplification will enable rapid mass deployment of DSL technology. The removal of the splitter removes the requirement of a "truck roll" by the service provider to install the device. This greatly facilitates mass deployment.


1. A queue of files waiting to be printed.
2. A container of network or serial cable.


A program that handles print jobs and places them in a queue for distribution and printing on one or more printers. Although this does happen on single user machines, this is usually only referred to as part of a network operation.


An often provided ISP channel that provides up to the minute coverage of sports both real and fantasy. For more information, contact your ISP.

Spotlight or Spot

SPOT is an acronym for Smart Personal Objects Technology. This is a technology released in early 2004 by Microsoft for eventual use in small personal hardware. The first personal object released is a watch that uses software and chips designed by Microsoft and licensed to the various watchmakers willing to come up with the fee. The technology runs on a wireless network used to send information to those devices, also created by Microsoft. And watches are only the first devices to be SPOT-enabled; the infrastructure could support many other such hardware ideas. The objective of SPOT gadgets is to present useful information at the point/time of a user's interest or need. This obviously includes common ideas and needs such as a weather forecast, financial market information, calendar items, traffic reports, reminders, news, up-to-the-second sports scores, lottery hype and news, Amber alerts, terrorism warnings, and other information that can be consumed in the bite-sized morsels these devices can display. As you could expect, this is predictably destined to be the most accurate watch you'll ever want, need or own. By no coincidence I'm sure, a version of MSN called MSN Direct is on the eminent release schedule for the device technology.

Spotlight or Spot

In the Spotlight, an AOL feature that highlights a different area of AOL every time you sign on. Most ISP services provide something similar. Many websites use a similar tactic for advertising of many clients.


1. A computer program designed to serve web pages from multiple hosts in order to optimize traffic between the hosts.
2. A hard disk that has a bad read-write head and is splattering data in different areas. This is fatal and should be replaced or repaired ASAP.


One of many ISP's network carriers. SprintNet can support speeds of up to 56K in most locations. They are currently upgrading dial-up services for faster rates through V.90 modems.


Short for Sequenced Packet eXchange, a transport layer protocol (layer 4 of the OSI Model) used in Novell Netware networks. This was a proprietary protocol used by Novell prior to the common use of TCP/IP. The SPX layer sits on top of the IPX layer (layer 3) and provides connection-oriented services between two nodes on the network. SPX is used primarily by client/server applications. Whereas the IPX protocol is similar to IP, SPX is similar to TCP. Together, therefore, IPX/SPX provides connection services similar to TCP/IP. This was popular in DOS days but is no longer required as the ONLY protocol by Netware products.


The acronym for Service Request, Service Release or Service Revision, take your pick. These are terms software companies use to denote a request for a particular software fix or the fix itself. It is usually followed by a number such as SR1234. In the case of a request, it is a way that a company can keep track of of an entire incident or group of incidents until a fix is made.


Acronym for static random access memory, and pronounced ess-ram. SRAM is a type of memory that is faster and more reliable than the more common DRAM (dynamic RAM). The term static is derived from the fact that it doesn't need to be refreshed like dynamic RAM. While DRAM supports access times of about 60 nanoseconds, SRAM can give access times as low as 10 nanoseconds. In addition, its cycle time is much shorter than that of DRAM because it does not need to pause between accesses. Unfortunately, it is also much more expensive to produce than DRAM. Due to its high cost, SRAM is often used only as a memory cache.


Acronym for server rack unit, a vertical measurement of 1.75 inches within a rack mount chassis. It is typically in the form of a number such as this; 4U, meaning 4 units or SRUs. See RMU and RME.


Signaling System 7 is a telecommunications protocol defined by the International Telecommunication Union (ITU) as a way to offload PSTN data traffic congestion onto a wireless or wireline digital broadband network. SS7 is characterized by high-speed packet switching and out-of-band signaling using Service Switching (SSPs), Signal Transfer Points (STPs), and Service Control Points (SCPs) (collectively referred to as signaling points, or SS7 nodes). Out-of-band signaling is signaling that does not take place over the same path as the data transfer (or conversation)--a separate digital channel is created (called a signaling link), where messages are exchanged between network elements at 56 or 64 kilobit per second. SS7 architecture is set up in a way so that any node could exchange signaling with any other SS7-capable node, not just signaling between switches that are directly connected. The SS7 network and protocol are used for:

- basic call setup, management, and tear down
- wireless services such as personal communications services (PCS), wireless roaming, and mobile subscriber authentication
- local number portability (LNP)
- toll-free (800/888) and toll (900) wireline services
- enhanced call features such as call forwarding, calling party name/number display, and three-way calling
- efficient and secure worldwide telecommunications


An acronym for Server Side Includes. A type of HTML comment that directs the Web server to dynamically generate data for the Web page whenever it is requested. There are various commands in the group that is supported or partially supported. The simplest and most common is command is #include, which inserts the contents of another file. This is especially useful for ensuring that boilerplate components, such as headers and footers, are the same on all pages throughout a Web site. To change a boilerplate element, you need only modify the include file, instead of updating every individual Web page. SSIs can also be used to execute programs and insert the results. They therefore represent a powerful tool for Web developers. There is no official standard for SSIs, so every Web server is free to support different SSIs in different manners. However, many SSI commands, such as #include and #exec, have become de facto standards. Web pages that contain SSIs often end with a .shtml extension, though this is not a requirement. The filename extension enables the Web server to differentiate those pages that need to be processed before they are sent to the browser.

SSL (Secure Sockets Layer)

Secure Sockets Layer protocol, a standard for transmitting confidential data such as credit card numbers over the Internet. Most true business sites support this feature which allows more security in data transmitted over the WWW. This is the standard minimum safe security level for true business on the Internet. The SSL protocol was developed by Netscape for transmitting various types of private documents via the Internet. SSL works by using a private key to encrypt data that is transferred over the SSL connection. Both Netscape Navigator and Internet Explorer support SSL, and many Web sites use the protocol to obtain confidential user information, such as credit card numbers. By convention, Web pages that require an SSL connection start with https: instead of http:. Another protocol for transmitting data securely over the World Wide Web is Secure HTTP (S-HTTP). Whereas SSL creates a secure connection between a client and a server, over which any amount of data can be sent securely, S-HTTP is designed to transmit individual messages securely. SSL and S-HTTP, therefore, can be seen as complementary rather than competing technologies. Both protocols have been approved by the Internet Engineering Task Force (IETF) as a standard.


1. In programming, a special type of data structure in which items are removed in the reverse order from that in which they are added, so the most recently added item is the first one removed. This is also called last-in, first-out (LIFO). Adding an item to a stack is called pushing. Removing an item from a stack is called popping.
2. In networking, short for protocol stack.
3. In Apple Computer's HyperCard software system, a stack is a collection of cards.
4. In programming, the memory area reserved for a predetermined amount of memory usage, as opposed to the heap.
5. Where "real programmers" keep work that is "yet to be done or in progress", a stack (usually a messy stack).
6. A "sorted by size" group of pancakes; two is considered a short stack.

stage directions

Used in chats to indicate vocal inflections, facial expressions, or body language. Usually surrounded by < > , for example < grin > and < hug > .

standard output

The place where default system output goes unless you specify a different output device. The standard output device is usually the video display screen. On older systems, that default is the console.

star network

A star is a network topology that connects all devices to a central location called a hub. Traditional star networks are designed to be easily expandable because hubs can be connected to additional hubs of other networks. A star is the opposite of a ring network. Also see BUSnetwork.


1. In communications, interference (static) that destroys the integrity of signals on a line. Noise can come from a variety of sources, including radio waves, nearby electrical wires, lightning, and bad connections. One of the major advantages of fiber optic cables over metal cables is that they are much less susceptible to noise. See crosstalk or noise.
2. In general, anything that prevents a clear signal or message from being transmitted. For example, you might hear someone complain of a lot of noise in a newsgroup, meaning that there are many superfluous messages that don't add anything to the discussion.
3. A particular kind of memory (RAM) technology.
4. See static electricity.
5. An assigned condition, such as a memory allocation or network address. The exact opposite of this condition is dynamic in reference to the computer industry.

static electricity

A form of electrical voltage and current generated in usually an accidental action. This is not electricity from a battery or the normal house of office electrical supply. It is more like lightning in that it is a quick but substantial discharge that can do great damage. It is the same type of charge that happens when clothes have been dried in a dryer and they cling to themselves upon removal. It occurs more frequently in cold weather, often while walking on carpet. It can destroy electrical components, disks, diskettes, tapes and other forms of magnetic storage media. It usually does this by demagnetizing the data and formatting markers on the media, and by over-charging electrical components capabilities.

status bar

1. A bar at the bottom of a window that is used to indicate the status of a task. For example, when you send an E-Mail message, you'll see the status bar filling with dots indicating that your message is being sent.
2. A watering hole that the elite visit and the wannabes frequent.


The art and science of hiding information by embedding messages within other, seemingly harmless messages. Steganography works by replacing bits of useless or unused data in regular computer files (such as graphics, sound, text, HTML, or even floppy disks ) with bits of different, invisible information. This hidden information can be plain text, cipher text, or even images. Unlike encryption, steganography cannot be detected. Therefore, it is used when encryption is not permitted. Or, more commonly, steganography is used to supplement encryption. An encrypted file may still hide information using steganography, so even if the encrypted file is deciphered, the hidden message is not seen. Special software is needed for steganography, and there are freeware versions available at any good download site. Steganography (literally meaning covered writing) dates back to ancient Greece, where common practices consisted of etching messages in wooden tablets and covering them with wax, and tattooing a shaved messenger's head, letting his hair grow back, then shaving it again when he arrived at his contact point.

stop word

As a part of the functionality of computer search engines, a stop word is a commonly used word (for example, "the", "a" or "an", among many others) that a search engine has been programmed to ignore, both when indexing entries for searching and when retrieving them as the result of a search query. During the building the index operation, most engines are programmed to remove certain words from any resulting index entry. The list of words that are not to be added is called a stop list. Stop words are deemed irrelevant for searching purposes because they occur so frequently in the language for which the indexing engine has been tuned. In order to save useless returns, space and time, these words are dropped at indexing time and then subsequently ignored at search time. Some search engines allow users to intentionally include a stop word in your search by putting an inclusion (plus sign) before each stop word in your query. Generally that is only used when searching for a particular phrase.


An abbreviation for Shielded Twisted Pair. See twisted pair and UTP.


A technology that sends data from one point to another in a continuous mass of data. This has been used for years in the tape backup industry. It is now emerging as a multimedia process for the Internet. Streaming video is a sequence of "moving images" that are sent in compressed form over the Internet and displayed by the viewer as they arrive. Streaming media is streaming video with sound. With streaming video or streaming media, a Web user does not have to wait to download a large file before seeing the video or hearing the sound. Instead, the media is sent in a continuous stream and is played as it arrives. The user needs a player, which is a special program that uncompresses and sends video data to the display and audio data to speakers. A player can be either an integral part of a browser or downloaded from the software maker's Web site. Major streaming video and streaming media technologies include RealSystem G2 from RealNetwork, Microsoft Windows Media Technologies (including its NetShow Services and Theater Server), and VDO. Microsoft's approach uses the standard MPEG compression algorithm for video. The other approaches use proprietary algorithms. (The program that does the compression and decompression is sometimes called the codec.) Microsoft's technology offers streaming audio at up to 96 Kbps and streaming video at up to 8 Mbps (for the NetShow Theater Server). However, for most Web users, the streaming video will be limited to the data rates of the connection (for example, up to 128 Kbps with an ISDN connection). Microsoft's streaming media files are in its Advanced Streaming Format (ASF). Streaming video is usually sent from prerecorded video files, but can be distributed as part of a live broadcast "feed." In a live broadcast, the video signal is converted into a compressed digital signal and transmitted from a special Web server that is able to do multicast, sending the same file to multiple users at the same time.

stub network

A network that only carries packets to and from local hosts. Even if it has paths to more than one other network, it does not carry traffic for other networks. See also backbone and transit network. It is the basis of an Intranet.


A specific method of compressing files on the Macintosh platform. Files compressed in this manner will usually end with .SIT. Most ISP's Macintosh software can stuff files sent through E-Mail. See Apple.


A subnet (short for "subnetwork") is an identifiably separate part of an organization's network. Typically, a subnet may represent all the machines at one geographic location, in one building, or on the same local area network (LAN). Having an organization's network divided into subnets allows it to be connected to the Internet with a single shared network address. Without subnets, an organization could get multiple connections to the Internet, one for each of its physically separate subnetworks, but this would require an unnecessary use of the limited number of network numbers the Internet has to assign. It would also require that Internet routing tables on gateways outside the organization would need to know about and have to manage routing that could and should be handled within an organization. The Internet is a collection of networks whose users communicate with each other. Each communication carries the address of the source and destination networks and the particular machine within the network associated with the user or host computer at each end. This address is called the IP address (Internet Protocol address). This 32-bit IP address has two parts
1. one part identifies the network (with the network number)
2. the other part identifies the specific machine or host within the network (with the host number)
An organization can use some of the bits in the machine or host part of the address to identify a specific subnet. Effectively, the IP address then contains three parts
1. the network number
2. the subnet number
3. the machine ID number


A small portable computer; generally it is self contained.

subrate multiplexing

A telephony term. The process of combining lower data rates into a single 64 Kbps channel signal.


A piece of a program that is "called" from another part of the program. Often a well-structured program will consist of a short main routine that calls many subroutines to do the work. Subroutines are individually tested sections of programming code and therefore, cut down the debugging and testing time when used and then used again in other situations. Programmers often have libraries of subroutines. A program that consists of mostly routines and subroutines is often called a subroutine sandwich by programmers. Subroutines are small in comparison to programs and are smaller than routines. A sub routine does one and only one job.


1. To add one's name to a mailing list.
2. A very small scribe.

subscriber line

The telephone line connecting the local Telco CO to the customer’s telephone instrument or telephone system.


The base layer of something. In the case of a chip, usually the lowest layer and the grounding layer. The substrate does not by definition have to be conductive, but usually is.


A particular type of operational amplifier where the output voltage is in proportion to the difference between the inputs. Unlike the comparator, which can be based on exactly the same IC, the Op-Amp has two individual inputs instead of one input and one reference value. This use is sometimes called a differential amplifier or proportional amplifier.


An item heading in a categorization or sorting process; For example, when ordering a pizza one may order toppings. There are different types of toppings: meats, cheeses, and vegetables. A sub-type of meats could be ham, pepperoni, or hamburger.


An extremely powerful mainframe computer. These specialized computers are used for intensive calculation, scientific simulations, animated graphics, and other work that requires sophisticated and ultra high-powered computing. Cray Research (now owned by Silicon Graphics), IBM, Fujitsu and DEC (now owned by Compaq) are the best known historic producers of supercomputers.


1. The framing format used in D4 transmission consisting of 12 consecutive frames. The 12 framing bits mark frame boundaries and contain the alignment pattern.
2. An informal term used to identify a very large and powerful mainframe computer, designated formally as supercomputers.


A communications surcharge is a charge, apart from your normal ISP membership fee, that may be billed to you as a result of the method you use to connect to your online service. For example, if you use certain local access numbers that are outside the United States when you connect to your service, such a surcharge may be added. These surcharges vary and are subject to change. For the latest surcharge information, contact your ISP or Telco. This term is often used also when transacting a very small amount on a credit card on the Internet. It is the equivalent of a handling charge when the purchase does not really justify the cost.

surge protector

A device, usually in the form of a multi-plug bar, that protects your computer from being damaged by power surges. The surge protection can either be from surges on the electrical input or in the case of modems, from surges on the phone lines.


Exploring online services or the World Wide Web. Commonly seen or known as "Surfing the 'Net" or in '60s terms, "cruising". Also see Password Surfing.


A coined abbreviation for Super-Video, a technology for transmitting video signals over a cable by dividing the video information into two separate signals. One signal for color (chrominance), and the other for brightness (luminance). When sent to a television, this produces sharper images than composite video, where the video information is transmitted as a single signal over one wire. This is because televisions are designed to display separate luminance, sometimes called the black and white information (Y) and chrominance (C) signals. The terms Y/C video and S-Video are the synonymous. Computer monitors, on the other hand, are designed for RGB signals. Most digital video devices, such as digital cameras and game machines, produce video in RGB format. The images look best, therefore, when output on a computer monitor. When output on a television, however, they look better in S-Video format than in composite format. To use S-Video, the device sending the signals must support S-Video output and the device receiving the signals must have an S-Video input jack. Then you need a special S-Video cable to connect the two devices.


A SVC is a switched channel to the end system that is only activated when information is passed from one end to the other. This allows for bandwidth that might otherwise be allocated to a permanent channel to be utilized to its full extent, and available at all times to active SVC’s. See also Permanent Virtual Circuit (PVC) and VC.


A telephony acronym for Simultaneous Voice and Data. See DSL.


Super Video Graphics Array. This is an enhancement from VGA monitors. SVGA monitors can display a resolution up to 1,024x768 and up to 16.7 million colors. See VGA.


1. In networks, a device that filters and forwards packets between LAN segments. Switches operate at the data link layer (layer 2) of the OSI Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs. Sometimes the switch is housed in a hub. See contact.
2. A small lever or button. The switches on the back of printers and on expansion boards are called DIP switches. A switch that has just two positions is called a toggle switch.
3. Another word for option or parameter, a symbol that you add to a command to modify the command's behavior. See toggle.
4. A word used to mean the CPU of an intelligent phone system.
5. An electrical device having two states, on (the closed state) or off (the open state). Ideally, a switch device has zero impedance when closed and infinite impedance when open.

switch hook flash

See hook switch flash.


The commonly used electronics term for the abbreviation for Voltage Standing Wave Ratio (VSWR). The ratio of the transferring signal voltage as compared to reflected signal voltage measured along the length of a transmission line. Check out our Voltage Standing Wave Ratio (VSWR) Loss Calculator.


The acronym for Super eXtended Graphics Array, a display specification that is capable of displaying 1280 x 1024 resolution, or about 1.3 million pixels.


See asymmetric as an opposing technology. Generally means like in process or activity in process. As an example, symmetrical transmission and reception would be transmitting and receiving at the same speed.


See asynchronous as an opposing technology. Data transmission using synchronization bytes, instead of start/stop bits, to control the transmission. In xDSL, video streams are considered to be synchronous in nature.


1. The set of rules, instructions and guidelines for a way of doing things. The term is usually associated with programming languages. The methodology to follow in order to correctly use the language.
2. The cost of doing something wrong.


1. The system administrator of a UNIX machine, or someone who maintains UNIX systems. See also root.
2. The administrator of a network, sometimes called Angel, a notch below the network God; the person who is responsible for the network operation and fixes the problems on a daily basis.
3. A Novell Guru.


System Operator, the manager of a bulletin board service. Often refers to the manager of an online or network area. Often a term, though less than complimentary, to refer to the MIS Director of a large organization. If you are in need of technical support from the MIS Director's organization, it is not to your benefit to refer to him as SYSOP. The SysOp is the down in the trenches, bit, bytes and ICs guy. The MIS Director is Lord of The Silicon, at least in his own mind and, (in his opinion) should be in the users' minds. Sysadmin is OK.

System 7

The Macintosh's latest operating system revision. As of this writing, 7.5.3 is the latest version of System 7. See
Apple. For more information, contact Bill Gates. Since he has a small financial stake in the company, he might enjoy your comments; then again, he might not. He can be reached through HTTP://WWW.MICROSOFT.COM



Systems Network Architecture - SNA

1. A proprietary networking architecture used by IBM and IBM-compatible mainframe computers.
2. A description of the logical structure, formats, protocols, and operation sequences that transmit information and that control the configuration and operation of an IBM network.

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