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Glossary
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scan. To read text, images, or bar codes into the computer. Accomplished by a device called a scanner.
ScanDisk. ScanDisk is a disk analysis and repair tool that was first released in Microsoft DOS 6.2 that checks a drive for errors and corrects any problems that it finds.
SCSI. Acronym for Small Computer System Interface. Pronounced "scuzzy," a standard for connecting multiple devices to a computer system. SCSI devices are connected together in a daisy chain, which can have up to seven devices (plus a controller) on it.
sector. To store data, disks are formatted into concentric rings called tracks, and each track is further divided into sectors. When a disk gets messed up to the point where the computer can't read information off it anymore, it's usually because one or two sectors are damaged.
serial. To transmit data, one bit after another, through a single cable. Serial contrasts with parallel, which is where data is sent eight (or more) bits abreast. The advantage of serial is that the information can be sent over longer distances.
serial port. A port (connector on the back of a PC) that allows data transfer, one bit at a time. Serial ports are sometimes called RS-232 ports. They come in 9-pin and 25-pin sizes.
server. A software package connected to a network that supplies information or services based on the requests of a connecting client program.
session. An individual activity being carried out by a miltitasking computer.
SGML. Abbreviation of Standard Generalized Markup Language, a system for organizing and tagging elements of a document. SGML was developed and standardized by the International Organization for Standards (ISO) in 1986. SGML itself does not specify any particular formatting; rather, it specifies the rules for tagging elements. These tags can then be interpreted to format elements in different ways. SGML is used widely to manage large documents that are subject to frequent revisions and need to be printed in different formats. Because it is a large and complex system, it is not yet widely used on personal computers. However, the growth of Internet, and especially the World Wide Web, is creating renewed interest in SGML because the World Wide Web uses HTML, which is one way of defining and interpreting tags according to SGML rules.
shareware. The term "shareware" refers to software that is distributed at low cost (sometimes at no cost), but which requires a payment (usually) and registration for full legal use. Copies distributed in this manner are offered on a trial basis. Shareware is not "free" software, for authors of shareware programs expect payment from those who intend to use the programs regularly. However, it does have the advantage over standard commercial software that users may thoroughly test a program to see if it's useful before making a purchase. While shareware may be freely copied, companies may not charge fees for copies that significantly exceed their duplication and handling costs. The authors of shareware programs also retain their copyright on the contents, and users may not modify such programs or distribute modified copies.
ShockWave. An extension for the Web that allows users to view multimedia content originally authored with Macromedia's Director tool.
signature. A signature is a small text file about yourself that can be appended to your e-mail messages and Usenet news postings by your mail program or newsreader. The contents of a signature file usually consists of your full name, a preferred e-mail address, brief information about your school, company, site, or occupation, and perhaps a witty remark or quote you wish to share with the world.
SIMM. Acronym for Single In-line Memory Module, which is a tiny circuit board that holds several memory chips.
SIP. Acronym for Single In-line Processor, a type of memory expansion card similar to a SIMM. The difference between a SIP and a SIMM is that the SIP uses a row of tiny pins as a connector. SIPs generally aren't user-upgradable and are usually installed in the factory only.
site. An area within an Internet server that provides information.
site license. A software agreement that lets you legally use multiple copies of the same program on several computers at the same time. Site licenses are cheaper than buying multiple copies of the same program, and they're legal, whereas software privacy is not.
SMTP. Simple Mail Transfer Protocol (SMTP). The protocol that supports messaging functions over the Internet. SMTP describes how e-mail servers should send and receive messages.
snail mail. Snail mail is computer slang for regular postal carrier mail.
software. Software generally refers to any type of computer program, from an operating system such as DOS, to a utility, to an application, to a program stored on a ROM chip. This contrasts from hardware, which is the physical side of computing. It's the software that makes the hardware go. Without it, the hardware would be nothing but potential.
software component. A reusable piece of software in binary form that can be easily integrated with other components with relatively little effort.
SoftServe. An easy way to download software that CIT has license to.
SOM. Short for System Object Model, an architecture developed by IBM that allows binary code to be shared by different applications. It serves the same purpose as Microsoft's competing COM standard. SOM is a full implementation of CORBA. A distributed version of SOM that allows binary objects to be shared across networks is known as DSOM.
spam. The term "spam" refers to a single article posted repeatedly to a large number of Usenet newsgroups or unsolicited, often irrelevant e-mail sent to a large number of e-mail addresses. While the definition of spam used to be strictly quantity-based, it has evolved to include any unsolicited commercial e-mail or news posting. "Spam" is a flagrant abuse of the Internet. In its worst form, mass postings or e-mailings are carried out by automated programs, which bombard dozens, or even thousands of addresses or groups with junk messages. Like telemarketers who annoy thousands of people with irritating phone calls in the hope of finding a few lucrative customers, "spammers" attempt to publicize their services or views through notoriety and sheer volume of posting. "Spam" is destructive for several reasons. It not only wastes the time of thousands of people who must wade through the junk postings to read articles of interest, it also wastes the money of those who must pay to read news or receive mail. If "spam" postings were not discouraged or restricted by system administrators, inboxes and news servers would be in danger of being swamped by junk articles, damaging the very medium such posters hope to exploit.
spikes. Most problems relating to electricity and electronic
devices can be traced to conditions known as line noise, over-voltage,
and under-voltage. Brownouts, spikes, surges, and sags are all terms which
refer to conditions of line noise, over-voltage, and under-voltage. Understanding
these conditions can help you make decisions regarding certain safety
measures available, and also when to take extra precautions when operating
electronics.
Whenever talking about voltage, and electricity
in general, it is important to remember that there are two major factors
to consider at all times. First, and most obvious, is the strength of
the signal. Second, you must also take into account the amount of time
such signal strengths may or may not be present.
For example, over-voltage is essentially
any voltage greater than what should normally be present on any given
power line. Most electronics devices, and especially computers, have internal
power supplies which are designed to handle moderate over-voltage conditions
(usually a 10 percent increase) for a very small amount of time without
damage. Spikes and surges are both examples of over-voltage conditions.
A spike (also referred to as a "transient") is a very short over-voltage
condition (billionths to millionths of a second), which is rarely harmful
to most electronic devices. A surge, on the other hand, can be quite harmful
to electronic devices. While surges are sometimes stronger in terms of
volts than spikes, usually the damage is done by the length of the surge
(thousandths of a second).
Under-voltage, understandably, is the opposite
of over-voltage. Sags, brownouts, and blackouts are all under-voltage
conditions. Sags rarely affect electronic devices, and while brownouts
will usually cause a computer to reboot due to moderate times of under-voltage
(lasting up to several seconds). Blackouts, of course, are long periods
(minutes to hours) of interrupted service.
spreadsheet. A program that organizes numbers, labels, and formulas in rows and columns for calculating results. Spreadsheets rapidly and accurately calculate results using mathematical formulas. Many spreadsheets have builtin statistical, mathematica, or financial equations (called functions) so users can focus more on entering in their numbers and less on creating the necessary equations.
stand-alone application. Applications designed to be operated on a single computer without requiring a network.
stand-alone computer. A computer that is not connected to a network.
standard. A definition or format that has been approved by a recognized
standards organization or is accepted as a de facto standard by the industry.
Standards exist for programming languages, operating systems, data formats,
communications protocols, and electrical interfaces.
From a user's standpoint, standards
are extremely important in the computer industry because they allow the
combination of products from different manufacturers to create a customized
system. Without standards, only hardware and software from the same company
could be used together. In addition, standard user interfaces can make
it much easier to learn how to use new applications.
Most official computer standards
are set by one of the following organizations:
static variable. A variable that retains the same data throughout the execution of a program. In contrast, a dynamic variable can have different values during the course of a program.
streaming. Instead of being required to transfer a file in its entirety before viewing it, streaming allows data to be downloaded in the background. Data appears to be displayed more quickly as a result
Stuffit. StuffIt is the de facto Mac OS standard for file compression and archiving. Unlike most other standards, it was designed with the Mac OS dual-forked file structure in mind and has the capability to store several files and even entire folder hierarchies all in one stuffed archive. Stuffed files can usually be identified by the .sit or .sea extension at the end of their filenames. Typically, when sent over e-mail or transferred via FTP or the Web, these archives will also be encoded in MacBinary II or BinHex, which add either a .bin or .hqx, respectively, after the .sit or .sea extension.
Stuffit Expander. StuffIt Expander is a simple application for decoding many kinds of encoded, compressed, and archived files. Developed primarily for Mac OS, there is also a version available for Windows.
style sheet. Style sheets are used to determine the appearance of HTML pages in a browser. They provide an easy way to change the visual appearance of a group of HTML files without changing each individual file.
subdirectory. A directory within or "under" the current directory. All disks have directories in which they store files. The directories can also store other directories, which are then called subdirectories. Technically, the term applies only to directories "beneath" another directory. Generally, any directory, except for the main or root directory, is called a subdirectory.
subnet mask. A 32-bit value that is used to distinguish the network ID portion of the IP address from the host ID.
subroutine. If a series of instructions are to be used many times in other sections of a program, it's possible to group these instructions together as a subroutine. Other portions of the program can execute the batch of instructions within the subroutine by merely calling that subroutine. Subroutines are identified by names and can often accept parameters to make their functions more generic.
supercomputer. The fastest type of computer. Supercomputers are very expensive and are employed for specialized applications that require immense amounts of mathematical calculations. For example, weather forecasting requires a supercomputer. Other uses of supercomputers include animated graphics, fluid dynamic calculations, nuclear energy research, and petroleum exploration. The chief difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe uses its power to execute many programs concurrently.
surfing. The act of following hypertext (or other) links across the World Wide Web to collect the information you want.
surge. An increase in the power level coming through the wall socket. Surges are gradual and build to a point where they may do some damage to your PC's components. Usually this is prevented by a circuit breaker or sometimes the power supply may actually give up to save the rest of the PC's components. A surge is the opposite of a brownout, when the power drops to low levels, and your PC may not even start at all.
SVGA. Short for Super VGA, a set of graphics standards designed to offer greater resolution than VGA. There are several varieties of SVGA, each providing a different resolution: 800 by 600 pixels; 1024 by 768 pixels; 1280 by 1024 pixels; 1600 by 1200 pixels. All SVGA standards support a palette of 16 million colors, but the number of colors that can be displayed simultaneously is limited by the amount of video memory installed in a system. One SVGA system might display only 256 simultaneous colors while another displays the entire palette of 16 million colors. The SVGA standards are developed by a consortium of monitor and graphics manufacturers called VESA.
synchronous. Occurring at regular intervals. The opposite of synchronous is asynchronous. Most communication between computers and devices is asynchronous -- it can occur at any time and at irregular intervals. Communication within a computer, however, is usually synchronous and is governed by the microprocessor clock. Signals along the bus, for example, can occur only at specific points in the clock cycle.
syntax. The rules regarding the way a language is put together. This applies to programming languages as well as human languages.
syntax error. This usually happens when writing a computer program. If you flip-flop words or misspell something, the program compiler spits out a syntax error.
system clock. An internal time clock maintained by the operating system. This clock is primarily used to record the time when files were saved to disk.
system disk. A disk that contains the system, or all the programs
required to start your computer. For the computers, the system disk is
the hard drive, which starts the computer each time it is turned on. You
can also start your computer from a floppy drive.
swap file. A swap file allows an operating system to use hard disk space to simulate extra memory. When the system runs low on memory it 'swaps' a section of RAM that an idle program is using onto the hard disk to free up memory for other programs. Then when you go back to the swapped out program it changes places with another program in RAM. This causes a large amount of hard disk reading and writing which slows down your machine considerably. This combination of RAM and swap files is known as Virtual Memory. The use of Virtual Memory allows your computer to run more programs than it could run in RAM alone.
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