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From: louie@umd5.UUCP
Newsgroups: net.unix,net.unix-wizards
Subject: Re: Tape drives and protection of tapes (using tar)
Message-ID: <462@umd5.UUCP>
Date: Sat, 6-Apr-85 17:50:57 EST
Article-I.D.: umd5.462
Posted: Sat Apr  6 17:50:57 1985
Date-Received: Tue, 9-Apr-85 00:23:24 EST
References: <1634@psuvax1.UUCP> <9638@brl-tgr.ARPA> <725@whuxlm.UUCP> <573@astrovax.UUCP>
Reply-To: louie@umd5.UUCP (Louis Mamakos)
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Organization: U of Md, CSC, College Park, Md
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Xref: linus net.unix:3515 net.unix-wizards:9880

In article <573@astrovax.UUCP> wls@astrovax.UUCP (William L. Sebok) writes:
>> If UNIX(tm) were really a user friendly system, it would support
>> `labeled' tapes and then you would have this problem. The system
>> would read the tape label before writing on it to ensure it really
>> was the one that was requested.
>
>Until you needed to handle a tape written elsewhere in which case the
>system would suddenly become very UNFRIENDLY.  Most of the time it has
>seemed to me that the fancy tape restrictions have just gotten in the
>way.  The trouble tends to be that each system thinks that it's tape
>format it the only one in existence.  The rest of the world is "FOREIGN".

Now wait just a minute!  That's what ANSI STANDARD tape labels are for.  The
labels are a standard format, not the data on the tape.  Even IBM systems
can recognize the tape labels written by a Sperry system.  The idea is that
the operating system processes the labels transparently to the user, such
that the user never sees the labels on the tape.  When the tape is mounted,
the OS reads the VOL1 label to verify that the reel number requested matches
the one on the tape.  There's more to it than that..

You obviously have never had one of your (unlabeled) tapes destroyed due 
to an operator mounting reel "P8610" instead of "P8601".
-- 
Louis A. Mamakos WA3YMH   University of Maryland, Computer Science Center
 Internet: louie@umd5.arpa
 UUCP: {seismo!umcp-cs, ihnp4!rlgvax}!cvl!umd5!louie