Problem reading a 4mm tape drive

UNIX AIX
1

I'm attempting to read a tape in a 4mm drive (AIX 4.3) using the following command...

tar tvf /dev/rmt0

...and I keep getting the following error message:

tar: 0511-193 An error occurred while reading from the media.
There is not enough memory available now.

I've googled this error message and found many sources (including this thread on this site) that indicate it is a problem with the block size on the tape being different from the block size on the drive. However, I've tried changing the block size on the drive to 0 (variable), 512, and 1024, using this command...

chdev -l rmt0 -a block_size=#

, and nothing is working. When I set the block size to 512 or 1024, the2second line of the error message changes to this:

tar: 0511-193 An error occurred while reading from the media.
There is an input or output error.

I'm afraid the drive might be broken, but I'm hoping someone might have some other suggestions for me. If I haven't included enough info, let me know.

TIA

2

I am not an expert but I read 4mm tapes alot. The command I use to read them is
tar -tvf /dev/rmt/0n

Hope this helps.

3

You can easily find the block size with the following commands.

#Change the block size to variable
chdev -l rmt0 -a block_size=0

#Read one huge block
dd if=/dev/rmt0 of=/tmp/testblock bs=128k count=1

#Find the block size with wc
wc -c /tmp/testblock

And there you have the blocksize.