Newsgroups: comp.unix.questions
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sdd.hp.com!decwrl!uunet!virtech!cpcahil
From: cpcahil@virtech.uucp (Conor P. Cahill)
Subject: Re: Can't cat tape- big blocks?
Message-ID: <1991Jun14.124934.104@virtech.uucp>
Organization: Virtual Technologies Inc.
References: <803@adpplz.UUCP>
Distribution: usa
Date: Fri, 14 Jun 91 12:49:34 GMT

martin@adpplz.UUCP (Martin Golding) writes:

>We got a 9 track tape in tar format, with 10k blocks. It's from a BSD type 
>system (at least, the tar headers match my sun manuals and tar from
>...
>When we cat it to a file (cat /dev/r50t >/dir/bigfile), it looks
>like we don't get all the data from the tape. We get the same effect
>if we rsh cat <the device>.

The problem is the blocking factor.  You must read data from a 9-track
drive in blocks that are at least as big as the block that was used to
write the tape.  So to get the data off your tape use:

	dd if=/dev/r50t of=whereever bs=10k

-- 
Conor P. Cahill            (703)430-9247        Virtual Technologies, Inc.
uunet!virtech!cpcahil                           46030 Manekin Plaza, Suite 160
                                                Sterling, VA 22170