The total system noise in the absence of information transmission.

The execution of lower priority computer programs when higher priority programs are not using the system resources.
Note: Priorities may be assigned by system software, application software, or the operator.

1. The practice of routing telecommunications traffic beyond its intended destination, and then back to the intended destination, usually for the purpose of taking advantage of tariffs or prices that are lower than those afforded by direct routing.
2. In security, to bring a call that has been routed along a particular path (usually via satellite) to some earlier position… (Read More →)

1. Radio wave propagation in which the direction of the incident and scattered waves, resolved along a reference direction (usually horizontal) are oppositely directed. A signal received by backscattering is often referred to as "backscatter. " [JP 1-02]
2. In optics, the scattering of light into a direction generally opposite to the original one.

1. [A] copy of files and programs made to facilitate recovery, if necessary. [INFOSEC-99]
2. See backup file.

A copy of a file made for purposes of later reconstruction of the file, if necessary.
Note: A backup file may be used for preserving the integrity of the original file and may be recorded on any suitable medium. Synonym job-recovery control file.

1. In data transmission, a secondary channel in which the direction of transmission is constrained to be opposite to that of the primary, i.e., the forward (user-information) channel.
Note: The direction of transmission in the backward channel is restricted by the control interchange circuit that controls the direction of transmission in the primary channel.
2. In a data circuit, the… (Read More →)

A signal unit (or sequence of bits) that (by changing its status) is used to request retransmission by the remote end whenever it receives a signal unit that is out of sequence. [T1.226-1992]

The reconstruction of an earlier version of a file by using a newer version of data recorded in a journal.

A field in a signal unit that contains the forward sequence number of a correctly received signal unit being acknowledged in the signal unit that is being returned to the sender. [After T1.226-1992]