Computer Science and Networking Glossary-T

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Shortcuts to Common Abbreviations and Acronyms
T
T1
T3
TB
TCP
TCP/IP
TMS34020
TPI
TSR
TXD

tap: 1. A connector that attaches to a cable without blocking the passage of information along that cable
2. In communications, a connection onto the main transmission medium of the network.
tape cartridge: A self-contained tape storage module, containing tape much like that in a video cassette. Tape cartridges are primarily used to back up hard disk systems.
tape drive: A computer peripheral that reads from and writes to magnetic tape. The drive may use tape on an open reel, or may use one of the small, enclosed tape cartridges. Because tape-management software has to search from beginning of the tape everytime it wants to find a file, tape is too slow to use as a primary storage system, but tapes are frequently used to back up hard disks.
T-connector: A T-shaped connector, used with coaxial cable, that connects two thin Ethernet cables and also provides a third connector for the network interface card.
TCP: Transmission Control Protocol. The connection-oriented, transport level protocol used in the TCP/IP suite of communications protocols.
TCP/IP: Transmission Control Protocol/Internet Protocol. A set of computer-to-computer communications protocols first developed for the Defencse Advanced Research Projects Agency (DARPA) in the late 1970's. The set of TCP/IP protocols encompass media access, packet transport, session communications, file transfer, e-mail, and terminal emulation.
TCP/IP is supported by a very large number of hardware and software vendors, and is available on many different computers from PCs to mainframes. Many corporations, universities, and government agencies use TCP/IP, and it is also the foundation of the Internet.
telnet: That part of TCP/IP suite used for remote login and terminal emulation; also the name of the program used to connect to the Internet host systems.
Originally a Unix utility, telnet is available now for almost all popular OSes.
temporary swap file: A sway file that is created every time it is needed. A temporary swap file will not consist of a single large area of contiguous hard disk space, but may consist of several discontinuous pieces of space.
tera-: Abbreviated T. A prefix meaning 10¹² in the metric system, 1,000,000,000,000; commonly referred to as 1 trillion in the American numbering system, and one million million in the British numbering system.
terabyte: Abbreviated TB. In computing, usually 2⁴⁰, or 1,099,511,627,776 bytes. A terabyte is equivalent to 1,000 gigabytes, and usually refers to extremely large hard-disk capacities.
terminal: A monitor and keyboard attached to a computer(usually a mainframe), used for data entry and display. Unlike a personal computer, a terminal does not have its own CPU or hard disk.
terminate-and-stay-resident program: TSR. A DOS program that stays loaded in memory, even when it is not actually running , so that you can invoke it very quickly to perform a specific task.
Calendars, appointment schedulers, calculators are all popular TSR programs. TSRs occupy conventinal memory space that becomes unavailable for use by your applications programs
terminator: A device attached to the last peripheral in a series, or the last node on a network.
text editor: In computer programming, software used to prepare program source code.
text file: A file that consists of text characters without any formatting information. Also known as an ASCII file, a text file can be read by any word processor.
thermal printer: A nonimpact printer that uses a thermal printhead and specially treated paper to create an image. The main advangtage of a thermal printer is that it is virtually silent. Thermal printers are used in calculators and in terminals to provide a local printing capability.
thick Ethernet: Connecting coaxial cable used on an Ethernet network. The cable is 1 cm thick, and can be used to connect network nodes up to a distance of approx. 3300 feet. Primarily used for facility-wide installations.
thin Ethernet: Connecting coaxial cable used on an Ethernet network. The cable is 5 mm thick, and can be used to connect network nodes up to a distance of approx. 1000 feet. Primarily used for office installations.
thrashing: An excessive amount of disk activity in a virtual memory system, to the point where the system is spending all its time swapping pages in and out of memory, and no time executing the application. Thrashing can be caused when poor system configuration creates a swap file that is too small, or when insufficient memory is installed in the computer. Increasing the size of the swap file and adding memory are the best ways to reduce thrashing.
thread: A concurrent process that is part of a larger process or progra. In a multitasking OS, a program may contain several threads, all running at the same time inside the same program. This means that one part of a program can be making a calculation, while another part is drawing a graph or chart.
TMS34020: A graphics chip from Texas Instruments used in high-end PC graphics adapters. The older 34010 uses a 16-bit data bus with a 32-bit data word, while the 34020 uses 32 bits for both. Both are compatible with the Texas Instruments Graphical Architecture (TIGA) used in some IBM-compatible computers. TIGA video adapters and monitors display 1024 pixels horizontally and 786 pixels vertically, using 256 colors.
token-ring network: A LAN with a ring structure that uses token-passing to regulate traffic on the network and avoid collisions.
On a token-ring network, the controlling computer generates a "token" that controls the right to transmit. This token is continuously passed from one node to the next around the network. When a node has information to transmit, it captures the token, sets its status to busy, and adds the message and the destination address. All other nodes continuously read the token to determine if they are the recipient of a message; if they are, they collect the token, extract the message, and return the token to the sender. The sender then removes the message and sets the token status to free, indicating that it can be used by the next node in sequence.
Token Ring network: IBM's implementation of the token-ring network architecture; it uses a token-passing protocol transmitting at 4 or 16 mbps.
Using standard telephone wiring, a Token Ting network can connect up to 72 devices; with shielded twisted-pair wiring, the network can support up to 260 nodes.
T1: A long-distance, point-to-point 1.544mbps communications channel that can be used for both digitized voice and data transmission;T1 lines are usually divided into 24 channels, each transmitting at 64 kilobits per second.
toner cartridge: The replaceable cartridge in a laser printer or photocopier that contains the electrically charged ink to be fused to the paper during printing.
touch screen: A special monitor that lets the user make choices by touching icons or graphical buttons on the screen.
tower case: A system unit case designed to stand on the floor rather than be placed on a desktop. Tower cases often have mor drive bays and expansion slots than the desktop units, and are commonly used for file servers and workstations.
track: A concentric collection of sectors on a hard- or floppy disk.
The outermost track on the top of the disk (or platter) is numbered track 0 side 0, and the outermost track on the other side is numbered track 0 side1. Numbering increases inwards towards the center of the disk. Tracks are created during the disk formatting process.
On tapes, tracks are parallel lines down the axis of the tape.
trackball: An input device used for pointing, designed as an alternative to the mouse. It is almost an upside-down mouse; it is stationary and contains a movable ball that you rotate using your fingers to move the mouse cursor on the screen.
tracks per inch: The number of tracks of sectors on a hard or floppy disk. TPI is an indication of the density of data that you can store on any given disk; the larger the TPI, the more data the disk can hold.
track-to-track access time: An indication of hard disk speed; the amount of time it takes the disk's read/write heads to move from one track to the next adjacent track.
transistor: Or tranfer resistor. A semiconductor component that acts like a switch, controlling the flow of an electric current. Transistors are incorporated into modern microprocessors by the million.
transport layer: The fourth of seven layers of the ISO/OSI model. The transport layer defines protocols for message structure, and supervises the validity of the transmission by performing some error checking.
Trojan horse: A type of virus that pretends to be a useful program, such as a game or a utility program, whn in reality it contains special code that will intentionally damage any system onto which it is loaded.
true color: A term used to indicate that a device, usually a video adapter, is capable of displaying 16,777,216 different colors.
T3: A long-distance point-to-point 44.736mbps communications service that can provide up to 28 T1 channels. A T3 channel can carry 672 voice conversations, and is usually available over fiber-optic cable.
twisted-pair cable: Cable that comprises two insulated wires twisted together at six twists per inch. In twisted-pair cable, one wire carries the signal and the other is grounded. Telephone wire installed in modern buildings is often twisted-pair wiring.
TXD: Abbreviation for transmit data. A hardware signal defined by the RS-232-C standard that carries information from one device to another.

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