SCO 2.2.1 tar question

[John Owens]

In article <100 at pigs.UUCP>, haugj at pigs.UUCP (John F. Haugh II) writes:
> > In article <8WQW5Ky00Vs8MSNUQN at andrew.cmu.edu> jl42+ at andrew.cmu.edu (Jay Mathew Libove) writes:
> > | % tar cf - /pathname | compress | tar cfk /dev/rfd096ds9 720 -

> this must be an april's fools day joke of some kind.  the person (jay libove)
> who posted the original article has made too many mistakes for this to be
> simple stupidity.

Actually, he's only made one mistake, and it's not a surprising one for
a UNIX neophyte.  (Be a bit more charitable.)

> first off, last time i checked there was no 96 tpi 9 sector device.  the
> only 96 tpi device was 15 sectored.

My xenix supports 96ds9 just fine - there's no reason not to use quad
density diskettes if you want to, and if he's running on some kind of
system other than an AT-compatible that has quad density but not high
density, that's what he'd want to use.  Certainly his 720k figure is
correct for 96ds9....

There are two ways to do what he wants to do, both with drawbacks.
One is

% cd / ; tar cf - pathname | compress | dd of=/dev/rfd096ds9 bs=1k

but this won't handle multiple diskette switching.

Another way is

% cd / ; tar cf - pathname | compress > /tmp/tar.Z
% tar cfk /dev/rfd096ds9 720 /tmp/tar.Z

but this won't work if you don't have enough tmp space to hold the
file (or if you're trying to tar something including /tmp).

If tar could read the contents of a fifo, you could get around this,
but it doesn't.

By the way, I used "cd / ; tar cf - pathname" instead of "tar cf - /pathname"
to make it easier to restore.  If the files in your tar archive start with
a '/', you can only restore them to their original locations.  If they
do not, they will be restored under the current directory, so you could
either cd / to restore them there or cd /somewhere-else to restore them
under /somewhere-else.

If anyone can expand on these suggestions to allow writing to multiple
diskettes, please post.  (I vaguely remember a program posted years ago
to write the standard input to multiple tapes/diskettes; if this
exists somewhere, it could probably be used as

% cd / ; tar cf - pathname | compress | multi-write /dev/rfd096ds9 720

or something like that.)

-- 
John Owens		SMART HOUSE Development Venture
john at jetson.UUCP	(old uucp) uunet!jetson!john
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