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From: jim@baroque.Stanford.EDU (James Helman)
Newsgroups: comp.sys.sgi
Subject: Re: utility for reading sun tar tapes
Message-ID: <JIM.90Nov5153059@baroque.Stanford.EDU>
Date: 5 Nov 90 23:30:59 GMT
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In-reply-to: layhe@dopey.rc.arizona.edu's message of 5 Nov 90 18:23:06 GMT

SGI 1/4" tapes are byte swapped wrt other vendors.  I believe this is
an historical artifact.  Something to do with the byte order of the
Multibus(?) on their old machines.

You can read Sun tar tapes using the "f /dev/tapens" option with tar,
e.g. "tar xvf /dev/tapens ."

On our machines, we actually made /dev/nrtape and /dev/tape point to
the non-swapped devices, i.e. /dev/nrtapens and /dev/tapens.  It
seemed rather silly to keep swapping bytes back and forth in software
to keep an anachronism which confused users transferring data between
Suns and 4Ds.  I believe that SGI's installation procedures go
straight to the /dev/mt/tpsXXXXX files, so such a change only affects
commands such as tar(1) and bru(1) which use /dev/nrtape and
/dev/tape.  It works for us anyway.

Jim Helman
Department of Applied Physics			Durand 012
Stanford University				FAX: (415) 725-3377
(jim@KAOS.stanford.edu) 			Work: (415) 723-9127