T
* Tag RAM
* Tag Switching
* Tape Drive
* Target Initiated Termination
* TC: Telecommunications Closet
* Tempest Shielding
* Terminal
* Terminator
* TFT: Thin Film Transistor
* Thermal Printer
* Thermal Wax Transfer
* TIA-232
* TIA-422
* TIA-423
* TIA-449
* TIA-530
* TLB: Translation Look-Aside Buffer
* Toggle
* Toner
* TPPMD: Twisted-Pair Physical Medium Dependent
* TPS: Transactions Per Second
* Trace Cache
* Trackball
* Transceiver: Transmitter-Receiver
* Transistor
* Tray Drive
* TTL: Transistor-to-Transistor Logic
* TWAIN
* Twisted-Pair Cable
tag RAM
Tag Ram is a specialized area of static RAM used to hold addresses. The actual data is stored in a different part of the cache, called the data store. The values stored in the tag RAM determine whether a cache lookup results in a hit or a miss. Tag RAM is used with hardware devices such as CPU caches to keep track of which memory addresses are stored in the cache.
tag switching
Tag switching, also called Label Switching, was orginally introduced by Cisco Systems, which uses tags (labels) containing forwarding information. Tag switching uses routers that sit on the periphery of the network and make forwarding decisions for all the routers in the backbone. They append this information to each packet in fixed positions in the header that can be quickly examined by interior backbone routers, saving the time involved in decoding the packet and its associated table lookups. Tag switching then was developed into the industrial standard technology called Multiprotocol Label Switching (MPLS).
tape drive
Tape drive, also known as a streamer, is a storage device that reads data from and writes it onto a magnetic tape or a punched tape. It is typically used for archival storage of data stored on hard drives. Tape drives are sequential-access, and must wind past all preceding data to read any one particular piece of data. They are not the fastest form of data storage, as they are sequential, but are long lasting and cost efficient. Tape drives can be connected with SCSI (most common), parallel port, IDE, USB, Firewire or Optical Fibre.
target initiated termination
Target initiated termination is a mechanism of the PCI architecture where the target of a data transfer is allowed to terminate a data transfer between it and the bus master of the target device monopolizes the bus due to slow access time. The target device will also terminate the transfer if it detects a collision on the bus. After the transfer has been terminated, the target device will issue a retry request to the PCI bus master.
Telecommunications Closet
Telecommunications Closet (TC), also called Wiring Closet, is a room or closet that houses all the telecommunication equipment. The TC also serves as a termination point for the horizontal cabling system of a network, the point of circuit administration and contains the network's distribution panels, cross-connects and backbone. The TC may also house auxiliary power supplies for workstation equipment.
Tempest shielding
Tempest Shielding refers to the shielding of devices from Electromagnetic Interference (EMI) and to ensure communications security (TEMPEST). The most sophisticated devices use advanced micro-components that have been designed from scratching to minimizing Tempest emanations. Generally, shielding involves encompassing the device in a Faraday cage that does not permit stray emanations, along with special modifications to the power source. This usually involves a heavy metal case around an object. Tempest shielding also involves such issues as the design of a room and placement of equipment within it, to ensure that no information can escape.
terminal
Terminal, or computer terminal consists of a keyboard and display screen (VDU) for a user to communicate with the computer. The terminal may be physically attached to the computer or linked to it by a cable. A 'dumb' terminal has no processor of its own, whereas an 'intelligent' terminal has its own processor and takes some of the processing load away from the main computer.
terminator
Terminator in the computer networking refers to device attached to the end-points of a bus network or daisy-chain to absorb signals so that they do not reflect back down the line.
TFT: Thin Film Transistor
Thin film transistor (TFT), also known as active-matrix LCD, is a type of LCD flat-panel display screen technology, in which each pixel is controlled by from one to four transistors. A thin film transistor (TFT) is a special kind of field effect transistor made by depositing thin films for the metallic contacts, semiconductor active layer, and dielectric layer.
thermal printer
A thermal printer produces a printed image by selectively heating coated paper when the paper passes over the thermal print head. The coating turns black in the areas where it is heated, producing an image. Two-color direct thermal printers are capable of printing both black and an additional color (often red), by applying heat at two different temperatures.
thermal wax transfer
Thermal wax transfer is a printing technology that adheres a wax-based ink onto paper. As the paper and ribbon travel in unison beneath the thermal print head, the wax-based ink from the transfer ribbon melts onto the paper. When cool, the wax is permanent. This type of thermal printer uses an like-sized panel of ribbon for each page to be printed, regardless of the contents of the page. Monochrome printers have a black panel for each page to be printed, while color printers have either three (CMY) or four (CMYK) colored panels for each page.
TIA-232
TIA-232, a popular physical layer interface, also known as EIA-232 or RS-232, is a standard for serial binary data interconnection between a DTE (Data terminal equipment) and a DCE (Data communication equipment). It is commonly used in computer serial ports. A similar ITU-T standard is V.24.
TIA-422
TIA-422, also known as EIA-422 or RS-422, is the balanced electrical implementation of EIA/TIA-449 for high-speed data transmission. Now referred to collectively with TIA-423 as EIA-530, it provides for data transmission, using balanced or differential signaling, with unidirectional/non-reversible, terminated or non-terminated transmission lines, point to point, or multi-drop.
TIA-423
TIA-423, also known as EIA 423 or RS-423, is the unbalanced electrical implementation of EIA/TIA-449 for EIA/TIA-232 compatibility.
TIA-449
TIA-449, also known as EIA-449 or RS-449, specifies the functional and mechanical characteristics of the interface between data terminal equipment and data communications equipment. The electrical signalling standards intended for use with RS 449 are TIA-422 for balanced signals, and TIA-423 for unbalanced signals, with a data rate up to 2,000,000 bits per second. The standard specified two D-subminiature connectors with 37 and 9 pins for the primary and secondary data circuits.
TIA-530
TIA-530, also known as EIA-530 or RS-530, is a balanced serial interface standard that generally uses a 25-pin connector. The specification defines the cable between the DTE and DCE devices. It is a replacement for EIA-449, which uses 37-pin connector. It is to be used in conjunction with EIA-422 and EIA-423.
TLB: Translation look-aside buffer
Translation Look-aside Buffer (TLB) is cache in a CPU that contains parts of the page table which translate from virtual into real addresses. This buffer has a fixed number of entries and is used to improve the speed of virtual address translation. The buffer is typically a content addressable memory (CAM) in which the search key is the virtual address and the search result is a real or physical address (which, perversely, may not be the same thing). If the CAM search yields a match the translation is known and the match data is used. If no match exists, the translation proceeds via the page table, which will take several more cycles to complete – particularly if the translation tables are swapped out into secondary storage. The TLB enables faster computing because it allows the address processing to take place independent of the normal address-translation pipeline.
Toggle
Toggle means to switch from one setting to another. A toggle switch is a generic class of electric switch that uses a mechanical lever, handle or rocking mechanism to actuate it. A toggle switch has just two positions. For example, light switches that turn a light on or off are toggle switches. On computer keyboards, the Caps Lock key is a toggle switch because pressing it can have two meanings depending on what the current setting is. If Caps Lock is already on, then pressing the Caps Lock key turns it off.
Toner
Toner is the ink used by copy machines and laser printers. Toner consists of a dry, powdery substance that is electrically charged so that it adheres to a drum, plate, or piece of paper charged with the opposite polarity.
TPPMD: Twisted-Pair Physical Medium Dependent
Twisted-Pair Physical Medium Dependent (TPPMD) is a technology by the ANSI X3T9.5 working group that allows 100 Mbps transmission over twisted-pair cables.
TPS: Transactions per second
Transactions per second (TPS) is a measurement used in computer hardware and software to determine how many transactions have been processed in one second.
Trace cache
Trace cache is an instruction cache in a microprocessor to reduce the required fetch bandwidth on the processing pipeline. Trace cache stores dynamic instruction sequences after they have been fetched and executed in order to follow the instructions at subsequent times without needing to return to the regular cache or the memory for the same instruction sequence. In trace cache, each line stores a snapshot, or trace, of the dynamic instruction stream.
Trackball
A trackball is a pointing device consisting of a ball housed in a socket containing sensors to detect rotation of the ball about two axes—like an upside-down mouse, but with the ball sticking out more. The user rolls the ball with their fingers to move a cursor. Tracker balls are common on CAD workstations for ease of use and, before the advent of the trackpad, on portable computers.
Transceiver: Transmitter-receiver
Generally, transmitter-receiver (Transceiver or TCVR) is a device that both transmits and receives analog or digital signals. In semiconductor devices, transceiver is designed to send and receive digital data over a line or cable. In computer networking, the term transceiver is a device that performs both transmitting and receiving functions that is in a common housing, sometimes designed for portable or mobile use, uses common circuit components for both transmitting and receiving which provides half-duplex operation.
Transistor
Transistor is a component that amplifies a signal or opens or closes a circuit. There are electronic transistors and semiconductor transistors. Transistors have become the key ingredient of all digital circuits, including computers. Today's microprocessors contains tens of millions of microscopic transistors, integrated into a small piece of semiconductor material.
tray drive
Tray drive is a type of drive which uses a flat tray to hold the media and the tray is ejected from the drive for media placement and retracted for playing (reading). For example, CD and CD-ROM drives are tray drives.
TTL: Transistor-to-Transistor Logic
Transistor-to-Transistor Logic (TTL) is a digital logic design in which bipolar transistors act on direct-current pulses. Many TTL logic gates are typically fabricated onto a single integrated circuit (IC). TTL ICs usually have four-digit numbers beginning with 74 or 54. A TTL device employs transistors with multiple emitters in gates having more than one input. TTL is characterized by high switching speed (in some cases upwards of 125 MHz), and relative immunity to noise. Its principle drawback is the fact that circuits using TTL draw more current than equivalent circuits using metal oxide semiconductor (MOS) logic. Low-current TTL devices are available, but the reduced current demand comes at the expense of some operating speed.
TWAIN
TWAIN is a standard for getting input from image scanners: an image capture API for Microsoft Windows and Apple Macintosh operating systems. The standard was first released in 1992 and is maintained by the TWAIN Working Group. TWAIN is typically used as an interface between image processing software and a scanner or digital camera. Nearly all scanners come with a TWAIN driver, which makes them compatible with any TWAIN-supporting software.
Twisted-pair cable
Twisted-pair cable is a type of cable that consists of two independently insulated wires twisted around one another for the purposes of canceling out electromagnetic interference which can cause crosstalk. The number of twists per meter makes up part of the specification for a given type of cable. The greater the number of twists, the more crosstalk is reduced. There are a few variations of the twisted pair cables: Shielded Twisted Pair (STP), Screened Shielded Twisted Pair (S/STP), Unshielded Twisted Pair (UTP), Foiled Twisted Pair (FTP), Screened Unshielded Twisted Pair (S/UTP), and Screened Foiled Twisted Pair (S/FTP).