Proposal to add a new modifier to SCSI Write commands. -Reply

Tue Dec 3 09:02:42 PST 1996

* From the SCSI Reflector (scsi at, posted by:
> The real goal ...
> "Mark the block" [to generate] "a CHECK
> CONDITION when read".  "without having to
> interfere with the data payload or ecc areas


Thought 1: Totally cool idea.

Thought 2 ...

One of the toy projects I might finish if I were
independently wealthy would be to see how much of
SCSI I could implement as a layer on the host
side.  In particular by branching on x12 Inquiry
data to cope with the vagaries of specific

Doesn't this idea boil down to a bitmap of all
LBA's, stored outside of the LBA's, which the host
can edit?

For LBA's that have a bit set, some i/o layer
generates a CHECK CONDITION when the LBA is
otherwise read OK?

If an OS wants this, filter the x25 read capacity
result, knock off a few blocks, and be happy?

If you think you're stuck with a disk format based
on the x25 read capacity result, rethink.  Win 95
claims a disk is corrupt if it once had long file
names and has since visited a Win 3.1 system.

If you're really convinced you're stuck, then
create a file somewhere and use that?

Pat LaVarre

P.S. (: Remember.  All i/f standards ask too much,
all parts cost too much, etc. etc. etc. :)

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