Your command worked (it should say 'setblk' instead of 'stblk').
These tapes have been generated with a simple tar command, e.g.

tar cv ...

so they are supposed to be 512-byte fixed blocks, right?
Sometimes the console message is (instead of 20 blocks residual):

st0: block wrong size, 4 blocks residual
st0(xasc0:5:0): Sense Key 0x05, data = 07 00 00 00 00 00

I made an experiment to reboot the system with 1.4.2 and the tape
can be read with 'tar' without problems. Could be something
related to the MI scsi interface?

Many thanks for your help.

Regards,

Dan

>Daniel Senderowicz said:
>> Hi guys,
>>
>> I switched a while ago to the MI kernel (in 1.5.2) and since then
>> I never had a chance to use the tape drive (tk50). Today I found
>> some troubles that I didn't have with the old kernel 1.4.2. In the
>> console I'm getting messages such as:
>>
>> st0(xasc0:5:0): Sense Key 0x05, data = 07 00 00 00 00 00
>> st0: block wrong size, 20 blocks residual
>>
>> Is that something in the hardware or some configuration that
>> hasn't been properly done?
>
>Looks like you probably have the drive configured for 512-byte fixed
>blocks and the file on the tape is a different size.  You might try
>something like this:
>
>mt -f /dev/nrst0 rewind
>mt -f /dev/nrst0 stblk 0
>dd if=/dev/nrst0 of=tapefile bs=20b
>
>(The "20b" block size passed to dd is based on the "20 blocks residual"
>error given above.)
>
>Hope that helps...
>
>Cheers,
>entropy
>
>-- 
>entropy -- it's not just a good idea, it's the second law.