<data> To delete something, usually superfluous, or to abort
an operation.
"Flush" was standard ITS terminology for aborting an output
operation. One spoke of the text that would have been
printed, but was not, as having been flushed. It is
speculated that this term arose from a vivid image of flushing
unwanted characters by hosing down the internal output buffer,
washing the characters away before they could be printed.
Compare drain.
2. To force temporarily buffered data to be written to more
permanent memory. E.g. flushing buffered disk writes to disk,
as with C's standard I/O library "fflush(3)" call. This
sense was in use among BLISS programmers at DEC and on
Honeywell and IBM machines as far back as 1965. Another
example of this usage is flushing a cache on a context
switch where modified data stored in the cace which belongs
to one processes must be written out to main memory so that
the cache can be used by another process.
