Tape Density

Tape density is a property that specifies the amount of data that can be written onto the tape. Most Sun-supported tape devices use the highest density capacity by default.

tar

The tar command is a user-level command for backing up and restoring files from tapes or diskettes. The tar command does not recognize file-system boundaries.

TAC

1.) Terminal Access Controller. Internet host that accepts terminal connections from dial-up lines.
2.) Technical Assistance Center. Cisco TACs provide technical assistance to partners and end users, and form the hub of Cisco global support.

Target Address

Target addresses such as t0, t1,and t3 correspond to the address switch setting that is selected for each device. An external disk drive usually has an address switch that is located on the rear panel.

TCP/IP Protocol Stack

The Open Systems Interconnect (OSI) Reference Model contains seven layers that define the functions of data communications protocols. Each layer represents a function performed when data is transferred. The protocols are like a pile of building blocks stacked one upon another. Because of this appearance, the structure is often called a stack or protocol stack. The TCP/IP model is a modification of the OSI model that uses the following 4 layers:

  • Network access layer
  • Internet layer
  • Host-to-Host transport layer
  • Application layer

TCP Large Window Support

Large window support is a feature of Request for Comment (RFC) 1323 which provides performance improvements when both parties of a TCP/IP session support the window scaling feature.

TCP/IP

Sun networking software is based on a specification known as the Internet Protocol suite. This specification is called Transmission Control Protocol/Internet Protocol (TCP/IP) after two protocols that make up the suite.

TERMCAP

The TERMCAP environment variable specifies a file that contains a list of various types of terminals and their characteristics. System V replaced the function of this file with the terminfo  directory.

The default value for TERMCAP is /etc/termcap.

Terminal

A terminal is an input/output device for a computer that usually has a keyboard for input and a video screen for output.

The software representation of a physical device, such as a window, that allows input from a keyboard and provides character-based output.

 

terminfo Database

terminfo is an abbreviation for terminal information. The /usr/share/lib/terminfo directory contains many subdirectories, each containing several files. Each of these files is named for, and contains a summary of the functional characteristics of, a particular terminal. Visually oriented programs such as vi make use of these files. The terminfo  directory is an alternative to the termcap file.

Text File

A text file contains ASCII text.

TFTP

Trivial File Transfer Program (tftp) allows users to transfer files to and from a remote machine. Because there is no user-login or validation within the tftp protocol, many remote sites restrict file access via tftp.

Thin Client

A thin client is a system that has no local disk. All applications reside on a server.

Thread

Thread is short for thread of control, which normally executes a sequence of instructions. This thread of control can be split into n-separate threads to take advantage of system capabilities.

Trans Metadevice

A trans metadevice is the device used for logging. It consists of a master device and a logging device.

Transaction Log

In the NIS+ environment, the transaction log is used by a master server to store changes to the namespace until they can be propagated to replicas. A transaction log has two primary components: updates and timestamps.

troff

troff formats text in the filenames for typesetting or laser printing. Input to troff is expected to consist of text interspersed with formatting requests and macros.

Trusted Host

A trusted host is a system that has permission to loginto a remote machine without supplying a password.