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From: bruce@cs.su.oz (Bruce Janson)
Newsgroups: comp.sys.mips
Subject: Re: Exabyte tape compatibility
Message-ID: <2387@cluster.cs.su.oz.au>
Date: 5 May 91 06:30:33 GMT
Sender: news@cluster.cs.su.oz.au
Lines: 33

In article <15793@helios.TAMU.EDU> han@eemips.tamu.edu (Kyongho Han) writes:
>..
>	SCSI 4L0: illegal block lenghth 129024, actual=192512
>	Tape read error while trying to set up tape
>	
>We are using the same command for backup on both machines.
>/etc/dump 0fubsd /dev/rmt/hc4 126 6000 54000 (filesystem)
>..

Yes, we had a possibly related problem here.
We used to do our dumps in big blocks (63KB?).
Then we upgraded some of our machines from 2030's to 3230's and
installed some new operating system releases as well.
Somewhere in there the exabyte drive lost its ability to read
our old backup tapes -- darn.
Apparently the legal maximum blocksize had dropped to 8KB.
Fortunately, we still had an old machine/os configuration
around attached to one of our exabyte drives so we copied all
our backup tapes (ho hum) from the old (big) blocksize to the new
(small) 8KB blocksize.

Today, our backups still use 8KB blocks.
In subsequent os releases MIPS may have changed the blocksize (up)
again but I haven't bothered to check.

So, try changing your (dump) blocksize from 63KB to something smaller.

Cheers,
bruce

Bruce Janson					Email:	bruce@cs.su.oz.au
Basser Department of Computer Science		Phone:	+61-2-692-3272
University of Sydney, N.S.W., 2006, AUSTRALIA	Fax:	+61-2-692-3838