Hello

Another of my experiments in destroying data.

When I issue an mt erase command to the Sony SDK 500 AIT tape drive, it just
reports command completed within 13 seconds, clearly it did not actually do a
proper erase.   However, I've recently found a SDK 500 service manual and
apparently in the six byte SCSI cdb, where the first byte would be 0x19 for the
command erase, the least significant bit of the second byte determines if the
drive only writes out 300 EOD's or writes out EOD's till the end of the defined
partition.   Obviously, I want the latter but currently have the former so I
need to know how to set that bit whenever a SCSI erase command is issued.

The OS is Solaris 2.7 and I've read through
/usr/include/sys/scsi/impl/commands.h and
/usr/include/sys/scsi/generic/commands.h in which presumably an appropriate
modification may achieve what I desire but what the change should be currently
eludes me.   Anyone out there that knows how to flip this one command bit?

If I can set the bit then I should be able to write scripts that does a
bpmedialist on my mail pool, freeze all tapes; unfreeze, vmchange to a hold
pool,  tpreq, mt erase, tpunmount, vmchange to scratch all expired frozen tapes
in the pool.   Run this script once a day and viola I've got enforced single
expiration date per tape and data overwrites on expiration.   If I can't set
this bit then I'm doomed to a daily trip to the server room with a hand
degausser, note this will be a real pain once the remote media servers get set
up since they'll be scattered all over the country.   I may be a frequent flyer
member but I certainly don't want to be that frequent.

Regards,
John I Wang
Sr. Systems Engineer
Steverson Information Professionals

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