[269] in Athena_Backup_System
Crippled Mode Spec written.
daemon@ATHENA.MIT.EDU (Bill Cattey)
Thu Jun 20 18:45:05 1996
Date: Thu, 20 Jun 1996 18:44:42 -0400 (EDT)
From: Bill Cattey <wdc@MIT.EDU>
To: athena-backup@MIT.EDU
/mit/athena-backup/doc/draft/crippled.{tex,ps} contains the latest
draft of the crippled mode spec.
The only thing missing is the format for the ABS Volume Report /
Crippled Mode Log.
The document is made a little big by my integrating in a version of the
ABS_SLAVEINT spect from the ABS Master spec.
One unexpected wrinkle: The crippled mode master needs to keep a file
containing active dump tapes. Here is why: We have the requirement
that we write only on blank tapes. The slave will not dump without
going through a tape label validation sequence to confirm that the tape
is properly labeled. So we need a little file to remember that there
are tapes that have been labeled and that are now ready for use with
particular dumps that have been initiated. (Actually, this file MIGHT
need mention of a tape pool.)
Without keeping track of the tapes and the labels we create, we could
initiate a bunch of dumps, and then there would be an uncontrolled race
to grab whichever blank tape was in one of several slaves.
Does this make sense to anyone?
I'll try and explain it when I'm rested.
Bye BYE for now.
-wdc
