background n.,adj.,vt.
[common] To do a task `in background' is to do it whenever
foreground matters are not
claiming your undivided attention, and `to background' something
means to relegate it to a lower priority. "For now, we'll just
print a list of nodes and links; I'm working on the
graph-printing problem in background." Note that this implies
ongoing activity but at a reduced level or in spare time, in
contrast to mainstream `back burner' (which connotes benign
neglect until some future resumption of activity). Some people
prefer to use the term for processing that they have queued up
for their unconscious minds (a tack that one can often fruitfully
take upon encountering an obstacle in creative work). Compare
amp off, slopsucker.
Technically, a task running in background is detached from the
terminal where it was started (and often running at a lower
priority); oppose foreground.
Nowadays this term is primarily associated with Unix, but it appears to have been first used in
this sense on OS/360.