NAME
pump – copy asynchronously via a large circular buffer |
SYNOPSIS
pump [ –b iando ] [ –d sleepms ] [ –f ofile ] [ –i ireadsize ] [ –k
KB–buf ] [ –o owritesize ] [ –s start–KB ] [ –S off ] [ –t minutes ]
[ file ... ] |
DESCRIPTION
Pump copies files (or standard input if none) to standard output
by using two processes, one reading and one writing, sharing a
large circular buffer, thus permitting the reading process to
get ahead of the writing process if the output device is slow
(e.g., an optical disc). This in turn can keep the output device
busy.
The pipeline dd | dd can approximate this, but pipe buffering
is limited to 64K bytes, which is fairly modest.
Options are: |
EXAMPLES
Append a venti(8) arena to a DVD or BD quickly.
|
SOURCE
/sys/src/cmd/pump.c |
SEE ALSO
cp(1), dd(1), ecp(1), cdfs(4) |
BUGS
Pump processes spin while waiting for the circular buffer to fill
or drain.
Dd, ecp and pump occupy slightly different niches but perhaps
some simplification is possible. |