*BSD News Article 71402


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From: messina@bvve.disney.com (Michael J. Messina)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: Cannot Read a SCSI Tape Written by an Unknown Machine
Date: 19 Jun 1996 02:14:01 GMT
Organization: The Walt Disney Company
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Mark Chapman (chapman@allmalt.cs.uwm.edu) wrote:
: I have a SCSI DAT tape that was written on an unknown machine type using
: tar.  The note says "no compression tar -xvf /dev/rmt/0".
: When I try to read it, the kernel says the record is too big?
: (ahc0:4:0): "WangDAT Model 3100 03.0" type 1 removable SCSI 2
: st0(ahc0:4:0): Sequential-Access density code 0x13, 512-byte blocks, 
: write-enabled
: ROOT@interlock:/u3>tar -xv
: tar: read error on /dev/rst0 : Input/output error
: st0: 128874-byte record too big
: ********************************

: Any hints?  I can easily read/write other tapes.
: I get the same message if I dd, cat, tar, or otherwise try to read the tape.


I can't really give an answer, but can make suggestions.
I mostly work on SGI's, but recently installed FreeBSD at home.
I don't have a dat at home though.

You are probably running into the typical unix-to-unix tape problems.
It sounds like either
1) the tape was written at a blocksize that is different than your default
	you need to guess the correct blocksize and use the variable 
	blocksize device.  I don't know what it is called in FreeBSD.

2) the tape has a different byte ordering than your drive
	you need to use byte-swapping


Sorry I can't give you more specific details, like I said I'm new to FreeBSD.


mike
--
Michael J. Messina
Network and Systems Administrator	| The Walt Disney Studios
messina@bvve.disney.com			| Buena Vista Visual Effects  R.I.P.