.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 Sony WORM jukebox consists of
50 disks divided into 100 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 50 is the
.I B
side of disk 0.
On Bootes,
the main file system is configured
on both sides of the first 45 disks,
platters 0-44 and 50-94.
Slots 46-49 are available for mounting
blank disks for making backup copies of platters.
To back up the logical 57th platter in the file system, which is physical platter 62,
insert the blank platter in the input
carrier and type
.P1
    wormingest 49
    wormcp 62 49
.P2
To have the backup disk have the
correct platters on its two sides,
the blank platter inserted should be the
.I B
side up of the disk containing the
backup of logical (and physical) platter 12.
When the copy is done, type
.P1
    wormeject 49
.P2