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From: dkeisen@leland.Stanford.EDU (Dave Eisen)
Subject: Re: HELP! problem with tar PC <-> SUN
Message-ID: <1992Nov12.234822.1273@leland.Stanford.EDU>
Sender: news@leland.Stanford.EDU (Mr News)
Organization: Sequoia Peripherals, Inc.
References: <BxJ7qx.2An@avalon.nwc.navy.mil> <1992Nov12.212714.6615@thunder.mcrcim.mcgill.edu>
Date: Thu, 12 Nov 92 23:48:22 GMT
Lines: 33
In article <BxJ7qx.2An@avalon.nwc.navy.mil>, dejesus@archimedes.nwc.navy.mil (Francisco X DeJesus) writes:
> Here's the problem: [...] [i]f a tape is written on the Sun with a
> blocking fator of 2, the PC reads it as a blocking factor of 20.
> [T]his is where the *REAL* problem comes in: [t]he client specifies
> that the "tar" command *HAS* to be used _WITHOUT_ telling it a
> specific blocking factor on either end [...].
>
I don't know about Interactive or Intel UNIX for the PC, but you
can solve this problem easily enough on SCO Xenix. Tar looks for
information about the source device in the file /etc/default/tar.
So if you set up an entry for a device named /dev/suntape with the
appropriate blocking factor, then the user can just run tar xv6
if this is entry 6 or tar xv if this is the default entry.
On the other systems, you can accomplish much the same thing by using
the usual trick of making tar a shell script that just sets up the
command line and calls /bin/tar.real with the appropriate parameters.
This probably still won't make him happy. He'll want to read tapes
that were created with a blocking factor of 20 using a blocking
factor of 20 and tapes that were created with a blocking factor of
2 using a blocking factor of 2. In other words, he wants tar to
be clairvoyent. If this is the case, all you can do is tell him that
he wants something impossible and hope you don't lose the business.
--
Dave Eisen Sequoia Peripherals: (415) 967-5644
dkeisen@leland.Stanford.EDU Home: (415) 321-5154
There's something in my library to offend everybody.
--- Washington Coalition Against Censorship