[75] in Athena_Backup_System
Re: Tape layout
daemon@ATHENA.MIT.EDU (dkk@MIT.EDU)
Thu Feb 9 15:36:31 1995
From: dkk@MIT.EDU
Date: Thu, 9 Feb 95 15:36:07 -0500
To: delgado@MIT.EDU
Cc: jweiss@MIT.EDU, athena-backup@MIT.EDU
In-Reply-To: <9502091548.AA01616@green-acres.MIT.EDU> (message from Diane Delgado on Thu, 09 Feb 1995 10:48:38 EST)
Jonathon> int timestamp; /* UNIX timestamp of the date the last write operation began */
So, you're proposing to have the tape label rewritten at the beginning
of the tape after the rest of the tape has been written? I don't know
how many tape drives that will work with, and it sure won't work with
a WORM drive (like a CD-Recordable drive). Do we need the last-write
time, as opposed to the start-time for the most recent tape use?
If I'm missing something, please explain what "date the last write
operation began" means.
Diane> We might want to consider using real eof markers
From what I remember of Exabyte drives (at least the old ones) the
inter-record gap is ridiculously large. Lots of separate tapes files
means lots of space lost. We could only fill one of those tapes to
about 2/3 theoretical capacity before running out of tape.
