How to get past end of cpio archive on tape

Daniel A. Graifer dag at fciva.FRANKLIN.COM
Fri Dec 14 06:42:12 AEST 1990


In article <1990Dec12.050414.15575 at bjm.wimsey.bc.ca> news at bjm.wimsey.bc.ca (News Login) writes:
>	I have this backup which I accidentally wrote a cpio archive over.
>However, the cpio archive is only 20 megabytes and therefore 1/3 of the tape.

I think what you are asking here is 'How do I read beyond the end of the EOF
mark on the tape'.  The problem is that, when whichever process you use to
read past the first file closes the device, it automatically rewinds.  There
should be a different device (same major, different minor number) that
is explicitly no-rewind-on-close.  On my PRIME EXL (386 MultiBusII/SCSI, ATT
Unix Sys V 3.1.2), I have:
$ l /dev/rct
total 0
crw-rw-rw-   2 root     sys        1,160 Dec 13 12:19 c0d5
crw-rw-rw-   1 root     sys        1,164 Jun 27 10:56 c0d5n
crw-rw-rw-   1 root     sys        1,165 Feb 18  1989 c0d5w
$
Controller 0 (SCSI) device 5 (cartridge tape) no-rewind is the second device
here.  Once you've that device, use cpio or dd to read to the end of it, then
reopen the either the regular or the no-rewind device with dd to suck in the
data beyond the EOF mark.  Don't forget to rewind the tape after the last 
read, before you pull it from the drive!

Good luck
Dan



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