Archive::tar tape0

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

I've inherited a non-working Windows process of periodically writing a tar to tape. I can interact with the tape as follows, for example:

mt.exe eject tape0
mt.exe load tape0
[download]

But I haven't figured out how to read the tape. The process was calling GNU tar from a batch file, and giving an "invalid argument" error. I'm trying the following with Archive::tar's ptar, and getting similar errors:

perl ptar -tvf tape0
perl ptar -tvf \\.\tape0
perl ptar -tvf //./tape0
[download]

Any tips on ptar? Thanks!

Comment on Archive::tar tape0 Select or Download Code

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Re: Archive::tar tape0 by jethro (Monsignor) on Jun 14, 2008 at 01:54 UTC
I would suggest temporarily substituting gnu tar on that machine with a shell script that prints out its arguments That way you can find out with which arguments tar is called by this process.	[reply]
Re: Archive::tar tape0 by starbolin (Hermit) on Jun 14, 2008 at 05:32 UTC
Tar reads and writes to the tape device by default (compiled-in device) specifying `tar -tf tape0` on the command line attempts to extract the tar file "tape0" in the current directory to stdout. To see the archive contents from the tape: `tar -t`. To extract from the tape onto disk: `tar -x`. If tar doesn't see the tape for some reason then using the -f switch with the full device path `tar -tvf /dev/tape0` may work or it may not work depending on whether /dev/tape0 is a valid block device on your system. One problem is that you may have to set the correct blocksize to avoid an error. Try a blocksize of 20. If all else fails you may need to delve into the driver code for your particular tape drive to see what parameters it expects. s//----->\t/;$~="JAPH";s//\r<$~~/;{s\|~$~-\|-~$~\|\|\|s \|-$~~\|$~~-\|\|\|s,<$~~,<~$~,,s,~$~>,$~~>,, $\|=1,select$,,$,,$,,1e-1;print;redo}	[reply] [d/l] [select]
Re^2: Archive::tar tape0 by Anonymous Monk on Jun 17, 2008 at 17:18 UTC
Thanks apl, jethro, and starbolin. I still cannot communicate with the tape drive with Archive::Tar or GNU tar; but I installed cygwin and can do this: `mount -s -f -b //./tape0 /dev/st0 tar -cf /dev/st0 *` [download] That's solution enough for me.	[reply] [d/l]
Re: Archive::tar tape0 by apl (Monsignor) on Jun 13, 2008 at 20:14 UTC
Warning: I've never used this... ptar x apparently extracts files. If you want to incorporate this ability in another program, Archive::Tar has a read method.	[reply]