[comp.unix.questions] tape to tape copy

bigjohn@manta.NOSC.MIL (John Morris) (09/12/90)

Problem: copying a tape that is in "boot" format.
One method involves the 'dd' command but this involves having enough
disk space to accomodate the file.
Question: Is there a way, if you have two cartridge tape drives, to
directly move the data from one tape onto the other through a reasonable 
size buffer.
My computers are SUN's, mostly 4's of one variety or another.  I have a couple
external SCSI cartridge tape drives and think this should be do-able.

by the way, how do you 'make' the boot format tape?

gwyn@smoke.BRL.MIL (Doug Gwyn) (09/13/90)

In article <1205@manta.NOSC.MIL> bigjohn@manta.NOSC.MIL (John Morris) writes:
>One method involves the 'dd' command but this involves having enough
>disk space to accomodate the file.

You should be able to "dd" from tape to tape, also.

>Question: Is there a way, if you have two cartridge tape drives, to
>directly move the data from one tape onto the other through a reasonable 
>size buffer.

There is also a simple utility commonly called "tcopy" for copying tapes
(or other files where preserving record size is important).  Look around
for it on your system; if you can't find it I could mail you a version.

The big problem with "streaming" tapes is that they are horribly slow
if you can't keep them streaming, which UNIX applications seldom can.

bob@wyse.wyse.com (Bob McGowen x4312 dept208) (09/13/90)

In article <1205@manta.NOSC.MIL> bigjohn@manta.NOSC.MIL (John Morris) writes:
>Problem: copying a tape that is in "boot" format.
>One method involves the 'dd' command but this involves having enough
>disk space to accomodate the file.
>Question: Is there a way, if you have two cartridge tape drives, to
>directly move the data from one tape onto the other through a reasonable 
>size buffer.

You could still use dd as follows:

   dd if=/dev/src_tape of=/dev/dest_tape bs=1024k
					    ^^^^

The buffer used in the above is 1M, substitute as you can for larger or
smaller.  The if above is the input_file, of is the output_file.

---deleted system types and boot tape creation question---
Bob McGowan  (standard disclaimer, these are my own ...)
Product Support, Wyse Technology, San Jose, CA
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