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From: guy@sun.uucp (Guy Harris)
Newsgroups: net.unix-wizards
Subject: Re: TAR DOES NOT SWAP BYTES
Message-ID: <2852@sun.uucp>
Date: Sat, 5-Oct-85 01:48:39 EDT
Article-I.D.: sun.2852
Posted: Sat Oct  5 01:48:39 1985
Date-Received: Mon, 7-Oct-85 04:46:54 EDT
References: <235@thunder.UUCP> <604@neuro1.UUCP> <2818@sun.uucp> <471@mtxinu.UUCP>
Organization: Sun Microsystems, Inc.
Lines: 24

> Agreed about cpio, but it's not clear that SysV has a real tar in all
> cases.  When I visited a site of ATTIS a couple of years ago, they
> insisted that I bring a cpio tape, since they weren't sure that their
> 3B20 tar could read tapes made on a VAX.  It turned out that I had left
> something off the cpio tape that was on my standard tar tape, so we
> caried the tar tape to a VAX, extracted the appropriate files, and
> write them out again with cpio to move them to the 3B.

I think the problem is with the 3B20 tape drive, not with "tar" on the 3B20.
Some tape controller (which I think they've junked in favor of a sane one)
imposes a rather small minimum block size; "tar cb 20 ..." exceeds this
limit.  This screws "cpio" over, too; this from CPIO(1) in the S5 User's
Manual:

	BUGS
	     ...The -B option does not work with certain magnetic
	     tape drivers (see UN32(7) in the UNIX System V Administrator
	     Reference Manual).

For some reason, the "tar" manual page doesn't contain a similar warning.
Perhaps the people who wrote it thought "tar" was a thing of the past, soon
to be completely replaced by "cpio".

	Guy Harris