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From: guy%gorodish@Sun.COM (Guy Harris)
Newsgroups: comp.unix.wizards
Subject: Re: tar
Message-ID: <19614@sun.uucp>
Date: Sun, 24-May-87 19:54:06 EDT
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Posted: Sun May 24 19:54:06 1987
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> What's the point of the 's' (swap bytes) option to tar?

What 's' option to "tar"?  There isn't one in the 4.2BSD "tar", nor
in the 4.3BSD "tar", nor in the S5R2 "tar", nor in the S5R3 "tar".

> What's the strange message in the documentation about "blocked
> archives"?

From the S5R2 "tar" manual page:

	The "b" option should not be used with archives that are
	going to be updated.  The current magnetic tape driver cannot
	backspace raw magnetic tape.

Similar words appear in other versions of the manual page.

Since the 4BSD magtape drivers support an "ioctl" to do special
functions such as backspace, the 4BSD "tar" was modified to use this
"ioctl", and the restriction in question was listed.

> By the way, how close is System V tar format to POSIX USTAR format?)

Except for the absence of a format code for symbolic links, it is
exactly as close to the POSIX format as the 4BSD format is, since
they are the *same* format.  (The symbolic link code is reserved, not
specified, by the POSIX format, since POSIX doesn't describe symbolic
links.)
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com