Computer Science

Satellite Microwave
A wireless network that utilizes microwave signals to transmit data.

Scanner
Converts information from the written page to digital information that can be used by the computer. Works similar to the scanning process in a photocopy machine.

Scatter Infrared
Transmission rates are slower with this type, as the signal is designed to bounce off of walls, ceilings, etc. until it reaches the receiver. The effective distance of the signal is limited to about 100 feet.

Scroll
To look at the parts of the page that fall below (or above) what you see on your screen. Using the long bar at the far right of the screen, place the cursor with your mouse on the small bar, hold down the left-click button and drag the bar up or down to "scroll" the page.

SCSI
Small Computer Systems Interface (pronounced "scuzzy') - A standard way of interfacing a computer to disk drives and other devices that require high-speed data transferring. Up to eight SCSI devices (seven plus a host adapter) can be connected to a port and can interface a computer to more than one hard disk, CD-ROM drive, a scanner and a tape drive.

Security
The system used to protect data on a network from unauthorized use.

Security Certificate
A file of information (usually a text file) that is used by the SSL protocol to establish a secure connection. The information in the file includes: information about who it belongs to, who it was issued by, a unique serial number or other unique identifier, valid dates, and an encrypted "fingerprint" that can be used to verify the contents of the certificate. Both sides of an SSL connection must possess a CA.

Serial
Transmission of one bit at a time over a single wire.

Server
The computer that runs the network operating system, manages security and administers access to resources.

Server
A computer that provides a service to other computers on a network. An HTTP server, for example, lets those who have network access to it make use of the WWW service.

Server Network
Requires a central server (dedicated computer) to manage access to all shared files and peripherals.

Server Software
Software that resides on a server.

Session Layer
The Session layer handles such things as security authentication, data transfer, acknowledgments (ACK), connection establishment and release.

Sharing
Allowing files to be shared from one computer to another.

Shielded Twisted Pair
A type of cable in which pairs of conductors are twisted together to prevent possible cross-talk from nearby wiring.

SIMM
Single-Inline-Memory-Module

Simplex
A uni-directional data channel, as opposed to duplex.

Single-Frequency Radio
Narrow-Band Radio Transmission

SIPP
Single-Inline-Pin-Package

Site
The location of a Web page on the Internet is referred to as a Site.

SLIP
Serial Line Internet Protocol, defined in RFC 1055, is software that allows the Internet Protocol (IP), normally used on Ethernet, to be used over a serial link.

SMAU
Smart Multistation Access Unit

SMDS
(Switched Multimegabit Data Service) -- A new standard for very high-speed data transfer.

SMM
System Memory Management

SMTP
Simple Mail Transfer Protocol is used to transfer E-mail between computers, usually over Ethernet.

SNMP
Simple Network Management Protocol, the Internet standard protocol defined in STD 15, RFC 1157, was developed to manage nodes on an IP network. SNMP is not limited to TCP/IP.

Software
Any program (set of instructions) that makes a computer carry out a task or function.

Spam (or Spamming)
Using e-mail or USENET as a broadcast medium. This is considered an inappropriate use for these systems. E-mail addresses can be collected from cookies or newsgroups, and messages (usually advertisements) are sent to large groups of people.

Speakers
Plays back sounds. Mostly used for producing error signals.

Spooling
Holding computer output before sending it to a printer. This enables the main program to run more quickly as it sends the output to the print spooler, which then distributes the output to the printer at the proper speed

Spread-Spectrum Radio
Spread-spectrum broadcasts over a range of frequencies, so it is less susceptible to eavesdropping. This type of transmission is commonly used to connect multiple LAN segments together.

SQL
Structured Query Language - A database programming language for sending queries. Most database applications can be addressed using SQL.

SRAM
Static Random Access Memory

SSL
Secure Sockets Layer - A protocol designed to enable encrypted, authenticated communications across the Internet. URL's that begin with "https" indicate that an SSL connection will be used. SSL provides Privacy, Authentication, and Message Integrity. Each side of the SSL connection must have a Security Certificate that they received from the other. Each side then encrypts its transmissions using information from both certificates thereby ensuring that only the intended recipient can de-crypt it. This also ensures that the data was sent from the source expected and that it was not tampered with.

Star Network
All computers are connected to a central point called a hub. The hub collects and distributes the flow of data within the network. In large networks several hubs may be connected. This is the easiest form of network topology to troubleshoot because all information goes through a hub making it easier to isolate problems.

Star Topology
A LAN topology in which all workstations are wired directly to a central workstation called a hub. If the hub fails, the entire network goes down.

Storefront
In e-commerce, a portal Web site that contains links to a variety of products for purchase.

Subnet Mask
Using binary addition, a router can determine what addresses are local and what addresses are for other subnets within the network.

Subnetting
The process of subdividing a network into logical units.

Superscalar
Technology found in Pentium processors allowing the Pentium to have two instruction pipelines thereby increasing the speed of processing.

Surfing
The process of browsing the Internet.

Surge Suppressor
Used to prevent large power spikes (lightning) from damaging a computer.

Switch Boxes
Allows the user to manually (can be automatic) switch cable connections so that one computer can use several different printers or devices with one parallel port.

Synchronous
Data is transmitted in packets containing more than one character. This is faster than asynchronous transmission because there is no start/stop bit between each individual character.

Syntax
Specific rules apply to how the symbols of programming language can be written in order to form meaningful statements that will be understood by the PC.

Sysop
Short for System Operator - The person responsible for the physical operation of a computer system or network resource. These functions include implementing the backup and maintenance strategies that the System Administrator has set in place.

System Bus
Supports the CPU, RAM and other motherboard components.

System Crystal
Determines the speed at which a CPU is operated (sets the clock speed), it is usually a quartz oscillator.