SUMMARY: Taring from one host to another

From: Morten K. Barfoed (
Date: Mon Apr 01 1996 - 02:51:21 CST

Hi all,

Last week I posed the following question:

>Hi All,
>I have one machine with an 8 mm tape-drive
>and another with a 4 mm tape drive.
>Now, I'd like to make a copy from a 44 mm
>tape to an 8 mm tape.
>Can I do that without using disk as
>intermedium ?

I got many answers - see list of contributors at
end of this summary.

Anyway, the general answer was to use the program
'dd', and I've done it thus:

dd if=/dev/<local 4 mm device> bs=20b | \
rsh <remote host> dd of=/dev/<remote 8mm device> pbs=20b

It worked without problems. Probably one could optimize
on the blocking factor.

Some suggested me to try with tar, but I just can't make that
work. The problems are:

1: tar doesn't allow you to specify a remote tape-drive.

2: So the way to do it would be similar to the one above.
   Now, here you'd want the (local) tar command to take input
   from a tape and write it to the standard-output. As far as
   I can see, that is not possible. I do believe that there's
   a GNU tar which will allow you to do this.

Some suggested to connect both drives to the same workstations
and use the tcopy-command. Thanks, I didn't know the command,
still it's to much of a hazzle to have to move the drives, and
it works only locally.

David Markowitz included a tape-copying tool, that he has made
himself. I found it easier to use the inbuilt commands, but haven't
tried out his tool quite yet.

So, thanks to all you guys and girls:
David Willard at

(- what a list - people from about 10 nations !)


Morten Krabbe Barfoed

Danish Space Research Institute phone: +45 35 32 58 30 (switch-board)
Juliane Maries Vej 30 phone: +45 35 32 57 20 (me directly)
DK 2100 Copenhagen East FAX: +45 35 36 24 75
Denmark e-mail:

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