harvey/sys/doc/fs/p7

.SH
Sync Copy and WORM Copy Processes
.PP
The
.CW scp
process
wakes up every ten seconds and
issues writes to blocks in the buffer cache
that have been modified.
This is done automatically on important
console commands such as
.CW halt
and
.CW dump .
.PP
The
.CW wcp
process also wakes up every ten seconds
and tries to copy a
.CW dump
block from the cache to the WORM.
As long as there are
.CW dump
blocks to copy and there is no competition for
the WORM device,
the copy will continue at full speed.
Whenever there is competition for the WORM
or there are no more blocks to
copy,
then the process will sleep ten seconds
before looking again.
.PP
The HP WORM jukebox consists of
238 disks divided into 476 sides
or platters.
Platter 0 is the
.I A
side of disk 0.
Platter 1 is the
.I A
side of the disk 1.
Platter 238 is the
.I B
side of disk 0.
On Emelie,
the main file system is configured
on both sides of the first 237 disks,
platters 0-236 and 238-474.