Multiple tape backups with cpio

[Andrew A. Burgess]

In article <75 at towers.UUCP> robert at towers.UUCP (Robert Hoquim) writes:
>gary at mic.UUCP (Gary Lewin) writes:
...
>If I had any complaint
>it would be the inability of any SCSI tape drive to do multiple tape
>backups.  (ie.  file systems larger than 150 megs in a single CPIO pass
>without breaking things down into subdirectories on that file system.)
>
>So I should ask this question:
>
>	Has anyone figured a way with a SCSI tape drive (Archive or Wangtek)
>to do multiple tape backups with CPIO?  Say a file system that is 300 megs
>that would take 2 tapes with cpio asking for another tape like it did with
>the older Non-SCSI Wangtek tape drives (60 megs).  There just doesn't seem
>to be any report from the driver to CPIO that the end of the medium has been
>reached and just hangs.
>

I use SCO UNIX 3.2 and on this system the way this works is that cpio
simply counts the bytes and then prompts you for a new tape when the
count reaches the tape size (the tape size is explicitly set by parameters
to cpio). No end of tape indication from the tape is required.
If ISC does not work this way you should be able to insert
a program into the pipeline (between cpio and the tape) that does this counting
and prompts you to change tapes. Similarly when restoring, cpio wouldn't
know the difference.

Anyone see any problems with this?

Andy

-- 
Andy Burgess
Consulting Software Engineer
uunet!cichlid!aab or uunet!silma!aab
aab at cichlid.com