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From: gwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>)
Newsgroups: net.unix
Subject: Re: write(2) to tape with odd byte count
Message-ID: <393@brl-tgr.ARPA>
Date: Fri, 6-Dec-85 11:18:01 EST
Article-I.D.: brl-tgr.393
Posted: Fri Dec  6 11:18:01 1985
Date-Received: Sat, 7-Dec-85 21:22:06 EST
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Organization: Ballistic Research Lab
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Oh, boy!  Magtape driver wars!

> Oh, you're talking about the System V VAX TU78 driver maybe?  It
> doesn't give you the error return, it quitely pads to the nearest
> "word" so your copy tape isn't really a duplicate of the original.

I don't have any experience with this driver but that's a bug.

> The 4.2BSD TU78 driver works with any byte count <= 63k.  The 4.3BSD
> driver will also do "read-reverse" error correction for soft tape
> errors, recognize end of tape (finally), report hardware failures in
> human readable form and survive controller power failures without
> crashing the system or hanging the tape drives (except on 11/750,
> which gets "panic: cbhung" after a while).

I hope they fix the driver so it moves to the next tape mark when
closed in non-rewind mode.  It's great fun to get the tail of a
file overwritten because of this misdesign feature.