Barrons Publishing Dictionary of Computer and Internet Terms 10th

shoeshine (slang) to move tape back and forth repeatedly like a shoeshine cloth, often done by tape drives that are experiencing media errors.

shortcut

1.in Windows, an ICON that serves as a LINK to a file or icon elsewhere on the same computer. Shortcuts let you put the same program or file into the menu system in more than one place. In Windows shortcut icons are recognizable by an arrow displayed in the corner, and they are represented by files with the extension .lnk in the directory corresponding to the folder in which they reside.

To create a shortcut, find the desired program or folder and right-click it. One of the menu options will be ”Create Shortcut.” Then cut and paste or drag the new shortcut to where you want it (usually your Desktop). Contrast ALIAS (Macintosh).

2.a faster way to access a command without having to pick it from a menu. Shortcuts are often indicated by underlined letters on menus; typing the letter (perhaps while holding down Alt) will take you directly to that menu selection. Some menus also indicate explicit shortcuts (such as Ctrl-S), which you can press at any time, even when that part of the menu is not on the screen.

shrinkwrap the clear plastic coating that covers the boxes in which commercial software is sold.

shrinkwrap license a software license that the purchaser is deemed to accept by opening the package. Obviously, if the license is hidden inside the package, there will be some difficulty enforcing it in court, and many provisions of shrinkwrap licenses have never been tested. See also COMPUTER ETHICS; COMPUTER LAW; EULA; LICENSE.

shrinkwrapped product a product packaged in SHRINKWRAP; a product that is sold in retail stores, not just through mail order catalogs or through personal contact with a specialist.

side effect an effect of a program or subprogram other than simply computing its output from its input. For example, this Java method swaps the two values in a two-element array, and also has the side effect of changing the global variable t:

static void swap(int a[]) { t=a[0];

a[0]=a[1];

a[1]=t;

}

Side effects are usually undesirable because they disrupt variables used by other parts of the program. If t were declared local, the side effect would not occur.

SIG

1.a special interest group within various organizations and online services.

2.a SIGNATURE FILE.

sigma

1. the uppercase Greek letter Σ, which stands for the sum of all possible values of an expression. For example,

3

∑(i + 1)

i=1

is read “the sum of i +1 from i =1 to 3” and stands for

(1 + 1) + (2 + 1) + (3 + 1).

2. the lowercase Greek letter σ, which stands for the standard deviation in statistics.

signature an identification code sent with a message identifying the sender of the message. See DIGITAL SIGNATURE.

signature file a file automatically appended to outgoing e-mail and Internet postings, giving the sender’s name, e-mail address, and other pertinent information. Many people use their signature file (“sig file”) as a means of artistic expression, containing elaborate displays of ASCII GRAPHICS, poetry, or favorite quotes. See also STATIONERY.

Users sometimes embarrass themselves by forgetting what is in their signature file. Inside jokes and funny mottoes can be quite out of place on serious correspondence such as job applications.

silicon the chemical element (atomic number 14) most often used to make semiconductor devices. Its electrical properties can be changed by adding small amounts of impurities. See INTEGRATED CIRCUIT; SEMICON-

DUCTOR.

Silicon Creek an area in suburban Atlanta, Georgia, extending from Buckhead to the city of Norcross, home to several important computer companies, including American Megatrends (AMI), Peachtree Software, numerous Internet service providers, and formerly Hayes and Quadram, makers of important early PC peripherals. Compare ROUTE 128; SILICON VALLEY.

Silicon Fen an area surrounding Cambridge, England, which is home to numerous computer and electronics companies and research labs, including a major Microsoft research facility. Compare ROUTE 128;

SILICON VALLEY.

Silicon Glen an area in Scotland comprising Glasgow, Edinburgh, and other nearby cities, home to numerous computer companies; over 25% of the PCs sold in Europe are reportedly produced there. Compare ROUTE 128; SILICON VALLEY.

Silicon Valley the Santa Clara Valley and surrounding area between San Jose and San Francisco, California, including the cities of Cupertino, Sunnyvale, and Palo Alto. It is the home of numerous semiconductor and computer companies, including Google, Hewlett-Packard, Intel, and Apple, as well as Stanford University. Compare ROUTE 128; SILICON CREEK.

silver gelatin print see GELATIN SILVER PRINT.

SIMM (single in-line memory module) a tiny printed circuit board to which several memory chips are attached. It plugs into a slot on a larger printed circuit board and is handled as if it were a single integrated circuit. See also DIMM.

simulation the process of representing the actions of one system by those of another. A computer simulation is a computer program that carries out a step-by-step representation of the actions of something in the real world. For example, a computer model of population growth can simulate the behavior of a real population. A deterministic simulation occurs when the future path of the system is exactly determined by the parameters of the system. A Monte Carlo simulation occurs when probabilities are known and a selection of random numbers is used to guide the system. See also EMULATION.

sin, sine the trigonometric sine function. If A is an angle in a right triangle, then the sine of A (written as sin A) is given by

sin A = length of opposite side length of hypotenuse

The function sin(a) in many programming languages calculates the value of sin A, if A is in radians. For an illustration, see TRIGONOMETRIC

FUNCTIONS.

single-board computer a complete computer that resides on a single printed circuit board, usually a small one. Single-board computers are often built into industrial equipment. See also EMBEDDED SYSTEM.

single-byte font a font that represents each character with a single byte, as in ASCII, ANSI, or EBCDIC, and is therefore limited to 256 or fewer characters. Contrast DOUBLE-BYTE FONT; UNICODE.

singleton something that is in a set by itself; the only member of a onemember set.

singleton variable in Prolog, a variable that occurs only once in a fact or rule. Since all variables are local, a singleton variable does not carry information from one place to another, and it should be replaced by an anonymous variable. See ANONYMOUS VARIABLE; PROLOG.

site license a software license that allows unlimited copying of a computer program for use by a single organization at a specified site. A site license is often much cheaper than the purchase of multiple copies. See also

SOFTWARE LICENSE.

six sigma a high standard in statistical quality control. In statistics σ (sigma) represents the standard deviation. If a production process is operating well, then there will be a very small standard deviation in measured performance. This means that only a small number of parts will be defective, and the defective parts will be a few standard deviations away from the mean. In theory, if only those parts that are more than 6 standard deviations away from the mean are defective, then less than 2 parts per billion would be defective. In practice, the six sigma standard is taken to mean 3.4 defects per million.

size see SCALE.

skew to bend a graphical object as shown in Figure 238. When you skew an object, you slide one side of its bounding box to the left or to the right. This will slant it or shift its bottom edge uphill or downhill. Skewing can be done interactively with the mouse, or, for more precision, the degree of skew can be specified in a dialog box.

FIGURE 238. Skew

skin a set of graphics and/or computer code that changes the appearance of a piece of software (Figure 239). For instance, Windows Media Player can be decorated with skins that change its color scheme, window shape, and overall appearance. In games with three-dimensional graphics, skins are also used to personalize the appearance of characters.

FIGURE 239. Skins

(two ways of displaying Microsoft Media Player)

SKU (stock keeping unit) a numbered warehouse bin or package; more generally, a code to identify a product being sold. SKU numbers are often used to identify merchandise in computerized inventory and POINT- OF-SALE SYSTEMS.

skunk works (slang) a group of engineers and programmers who are deliberately isolated from their employer in an attempt to foster creativity and boost morale.

www.skype.com.

slash the character /, as opposed to the backslash \.

Slashdot a popular web site (www.slashdot.org) that provides technologically oriented news for computer enthusiasts. Most of the news stories are contributed by readers. Rob Malda created Slashdot in 1997. It is now owned by OSDN, a subsidiary of VA Software Corporation.

The name was chosen so that “slashdot.org” would be confusing when read aloud (“slash dot dot org”).

slave

1.the dependent unit in a pair of linked machines. Contrast MASTER (definition 1).

2.one of a pair of IDE hard disks or other devices connected to the same IDE cable. Generally, jumpers have to be set on IDE devices to identify them as master and slave. Contrast MASTER (definition 2).

sleep transistor a transistor that cuts off power to an electronic circuit when it is not needed, enabling it to “sleep” and be turned on again electronically.

slide a single image in a graphical presentation. The slide can be textual, pictorial, or graphical. Slides can also contain animations, sounds, music, and video. See PRESENTATION GRAPHICS.

slide sorter an on-screen representation of an entire graphical presentation. The individual slides are shown in rows, very small. It is then easy to reorder the slides, assign special effects and timings to the slides, or select the next slide to work on.

SLIP (Serial Line Internet Protocol) an adaptation of TCP/IP for DIAL-UP NETWORKING. Compare PPP.

slot a socket in a microcomputer designed to accept a plug-in circuit board.

See CARD.

SLR (single-lens reflex) a camera that contains a mirror in front of the film or image sensor, so that the viewfinder can use the same lens that will actually take the picture. When a picture is taken, the mirror flips up before the shutter opens.

Unlike most other cameras, SLRs normally have interchangeable lenses, and the user can see exactly what the picture will look like with any lens. See also DSLR.

small caps a specially designed alphabet of capital letters that are approximately two-thirds the cap height of the font, LIKE THIS. Text set in small caps has the same visual texture as normal text but gives the emphasis of setting text in all caps. The cross references in this book are set in small caps. See C/SC; EVEN SMALLS.

snap to grid a mode in which a drawing program lines up all objects on a (nonprinting) grid. This makes it easy to line up parts of diagrams that are drawn separately, rather like drawing with a pencil on graph paper.

sneakernet (slang) the practice of transferring files from one computer to another by carrying a diskette across the room.

sniffer a hardware device or computer program for intercepting data packets as they pass through a network either to test the network or to intercept other people’s confidential data. See FIREWALL.

snowflake see FRACTAL; KOCH SNOWFLAKE.

SOAP (Simple Object Access Protocol) a protocol for executing methods (procedures, functions, subroutines) on a remote computer using XML to encode the data and HTTP to perform the data transmission. SOAP can be used by COM, CORBA, and other kinds of distributed applications. See COM; CORBA; HTTP; PROTOCOL; XML.

social networking site a web site where users can build a personalized community to socialize with. Common features include a customizable profile, the ability to add other users as friends, the ease of sharing pictures, music, text, and links, and built-in chat and mail features. Social networking sites are becoming one of the most popular methods of contacting friends and organizing gatherings.

Social networking sites are often criticized for the amount of time that they can consume, and many schools and libraries specifically block them. There is concern that advertising is often mixed in with content seamlessly and the term FRIEND has lost much of its original meaning when applied to every acquaintance. There are also numerous privacy concerns, particularly with younger users who may be too eager to share personal information with strangers.

social responsibility see EICC.

socket

1.an electrical connector into which another connector, with pins, can be inserted.

2.a communication path between two computer programs not necessarily running on the same machine. Sockets are managed by a socket DEVICE DRIVER that establishes network connections as needed; the pro-

grams that communicate through sockets need not know anything about how the network functions.

Sockpuppet a fake online identity created by another user so that the user talks through another mouthpiece while pretending not to (like a literal sock puppet). Sockpuppets often pop up in forums to defend the original person’s arguments or to deliver praise in order to make the user seem more popular.

SODIMM (Small Outline Dual Inline Memory Module) a smaller type of DIMM commonly used in laptop and notebook computers. See DIMM.

soft brush (in paint programs) a category of tools that includes paintbrushes, airbrushes or spray cans, smear paintbrushes, and clone tools. All of these tools leave soft edges and have transparent strokes. These tools are sometimes grouped together in the toolbox and have similar dialog boxes for their settings.

soft copy computer output that is only viewable on the computer screen.

Contrast HARD COPY.

soft edge in a graphical image, a boundary between two areas that is diffuse and somewhat blurred. See Figure 127, page 226.

soft error an error or defect on a data storage device that is present only intermittently; an error that goes away when the same operation is tried again. Contrast HARD ERROR.

soft hyphen a hyphen that is used only when the word falls at the end of a line; sometimes called a DISCRETIONARY HYPHEN. Contrast HARD HYPHEN;

REQUIRED HYPHEN.

soft page, soft page break an invisible control code that indicates where the text will break at the end of a page. Unlike a HARD PAGE, a soft page break is inserted by the program and will move if the amount of text on the page changes. See WRAP.

software programs that tell a computer what to do. The term contrasts with hardware, which refers to the actual physical machines that make up a computer system. The hardware by itself is of little value without the instructions that tell it what to do.

Software can be classified into system software (see OPERATING SYSTEM) and application software. For examples of common types of application software, see WORD PROCESSING, SPREADSHEET, DATABASE MANAGEMENT. For information on creating software, see PROGRAMMING and PROGRAMMING LANGUAGE.

software engineering the art and science of designing and constructing software. The computer industry has learned from bitter experience that large programs cannot be constructed as casually as small ones. Some principles of software engineering include the following:

1.Before starting a project, estimate the amount of labor it will require, based on previous experience. Err on the side of caution. Do not reduce an estimate just because a manager or customer wishes it were lower.

2.Allow adequate time for planning. Decide exactly what is needed, and if possible, write some of the documentation for the finished product before starting to write the program.

3.“Freeze” the specifications when planning is complete. Make sure clients and higher management understand that any further changes will delay completion and raise costs. The only exceptions are changes proposed by the programmers in order to simplify implementation and improve performance.

4.Set priorities. Which is more important, finishing on time or implementing the full set of features? Can the product be developed incrementally, as a minimal first version followed by upgrades?

5.Use reliable programming techniques, including STRUCTURED PROGRAMMING and appropriate use of COMMENTs.

6.Insist that programmers remove errors as soon as they are found; do not leave debugging for later. You cannot build the upper stories if the foundation is not solid.

7.Keep programmers’ morale high. Long working hours, although traditional in Silicon Valley, do not increase productivity; few people really work more than eight hours a day no matter how long they are at the office.

8.Do not add personnel to a project that is running late; the time taken to orient the new programmers will delay it further. Instead, find ways to help the current programmers work more efficiently. Shield them from unnecessary meetings, administrative chores, and even telephone calls.

9.Deadline crises are a symptom of incompetent management. A well-managed project gets finished on time without going into “crunch mode.” If a manager does not know how long a project will take, that’s not the employees’ fault. If the time needed cannot be estimated in advance, everyone should realize it rather than

relying on wishful thinking.

See also COMMENTS; CREEPING FEATURISM; STRUCTURED PROGRAMMING.

software interrupt see INTERRUPT.

software license an agreement between the publisher of a computer program and the person who buys a copy of it, allowing the software to be used.

Some licenses specify that when you buy a copy of a program, you do not really own the copy but have merely bought the right to use it in certain ways. Normally, the license allows you to make a working copy of the program, which would otherwise be forbidden by copyright law (see

COPYRIGHT).

Most licenses allow a single copy of the program to be used on only one machine at a time. It can be copied for backup purposes, and it can be moved from one machine to another, but it cannot be actually in use in two places at once. Thus you are forbidden to load the same program into more than one machine through a network (see LOCAL-AREA NETWORK). However, it is usually permissible for several people to use the same program on a multi-user machine with a single CPU.

A site license allows unlimited copying of a program for use by a single organization at a specified site. A site license is often much cheaper than the purchase of multiple copies. Another alternative for schools and colleges is the use of student editions of software; these are less powerful than the commercial versions and are sold at much lower prices.

Many aspects of software licenses have not yet been tested in court. In particular, the license document is sometimes packed where the user cannot see it until after buying and opening the software package. In such cases, it can hardly be described as a valid contract. When dealing with