multiplexing

1. communications (Or "multiple access") Combining several

signals for transmission on some shared medium (e.g. a

telephone wire). The signals are combined at the transmitter

by a multiplexor (a "mux") and split up at the receiver by a

demultiplexor. The communications channel may be shared

between the independent signals in one of several different

ways: time division multiplexing, frequency divisionmultiplexing, or code division multiplexing.

If the inputs take turns to use the output channel (timedivision multiplexing) then the output bandwidth need be no

greater than the maximum bandwidth of any input.

If many inputs may be active simultaneously then the output

bandwidth must be at least as great as the total bandwidth of

all simultaneously active inputs. In this case the

multiplexor is also known as a concentrator.

(1995-03-02)

2. storage Writing multiple logical copies of data

files. Placing the copies on totally separate paths to

mirrored devices greatly reduces the probability of all

copies being corrupt. Multiplexing differs from mirroring in

that mirroring takes one data file and copies it to many

devices, thus making it possible to copy a corrupt file many

times. Multiplexing writes the data files to many places

simultaneously; there is no "original" data file.

(2001-05-10)