Sampling
The process of converting analog data into digital data by taking a series of samples or readings at equal time intervals.

Saturation
The extent to which one or two of the three RGB primaries predominate in a color. As quantities of RGB equalize, color becomes desaturated towards grey or white.

Scanner
A device that converts images (such as photographs) into digital form so that they can be stored and manipulated on computers.

Screen Frequency
The number of rows or lines of dots in a halftone image within a given distance, normally stated in lines per inch (lpi) or lines per centimeter (lpm). A frequency of 200 lpi would only be used in high-quality printing.

Screen Ruling
Another term used for screen frequency.

Screen Saver
A moving picture or pattern that is displayed on the screen when no activity takes place for a specified period of time.

Scripts
A type of program that consists of a set of instructions for another application or utility to use.

Scroll Bar
The bar that appears at the right side or the bottom of a window that contains more information that can be displayed. The scroll bar is used to scroll an object or parts of a document into view when the entire object or document does not fit in the window.

SDSUnet
San Diego State University Network. The backbone network that connects multiple buildings on the SDSU campus.

Search Engines
A type of software that creates indexes of databases or Internet sites based on the titles of files, key words, or the full text of files.

Second Original
High-quality, contone reproduction of an image, intended to be identical to the original.

Secondary Color
Color obtained by mixing two primary colors. Although known as primary colorants, C,M, and Y are the secondary colors of light. Red plus green produce yellow, for example.

Serial Cable/Serial Port
A cable used to connect peripheral devices through a computer's serial port. Normally a 25-pin connector on each end, yet can be a 9-pin on one. A Serial Port can either be plugged into an expansion slot on the motherboard of your computer or built into the motherboard itself. Serial ports are used for such devices as printers, mice, and modems.

Server
A computer that shares its resources, such as printers and files, with other computers on the network. An example of this is a Novell NetWare Server which shares its disk space with a workstation that does not have a disk drive of its own.

Service (NT service)
A process that performs a specific function in Windows NT and can be called by various other programs. Windows NT provides tools to monitor and administer services.

Shadow
The darkest area of an image.

Shareware
Software that you can try before you buy. It's distributed through on-line services, BBSs, and user groups. You're allowed to try it out and give copies to others, but if you want to keep using it, you must pay the registration fee.

Shockwave
A set of programs that allow Macromedia Director animation files to be played over the internet with a web browser.

Site
Organization or facility where a host is located.

Site-license
Through negotiations with a vendor, a renewable fee has been paid to allow a fixed number of copies of copyrighted software at one site.

SLIP
Serial Line Internet Protocol. A protocol used to run IP over serial lines, such as telephone circuits or RS-232 cables, interconnecting two systems.

SMTP
Simple Mail Transfer Protocol. Internet standard protocol for transferring electronic mail messages from one computer to another. SMTP specifies how two mail systems interact and the format of control messages they exchange to transfer mail.

Socket
Logical address of a communications access point to a specific device or program on a host.

SPAM
Refers to the practice of blindly posting commercial messages or advertisements to a large number of unrelated and uninterested newsgroups.

Speckling
Isolated light pixels in predominantly dark image areas, sometimes caused by incorrect readings or noise in the scanning device.

Spectral Highlight
A bright reflection from a light source containing little or no detail.

Spectrophotometer
An extremely accurate color measurement device using a diffraction grating to split light into its components wavelengths, which are then measured by numerous light sensors.

Spreadsheet
A number-related document whereby calculations and formulas are applied to the data organized in rows and columns of cells.

SQL
Structured Query Language, a syntax used by many database systems to retrieve and modify information.

Staircasing
See Aliasing.

Start/Stop Bits
A start bit signals the start of a unit of data in asynchronous communications. A stop bit signals the stop of a unit of data. The unit can vary in length depending on the protocol.

Subnet Address
An extension of the Internet addressing system that allows a site to subdivide a single Internet address to cover multiple physical networks. This is done by dividing up the host address part of an IP Address into a local network number and host address number.

Substrate
The base material used to carry out or support an image, for example, paper or film.

Subtractive Primaries
Another term for primary colorants.

Supersampling
The capture of more grey levels per color than is required for image manipulation or output. This additional data allows shadow details to be heightened, for example.

Syntax Error
Occurs when a user (or programmer) has put words in an order that a program does not understand.