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Re: cdrecord and scsi-3 compliance

>From: Andy Polyakov <appro@fy.chalmers.se>

>> >> In any case, the low level transport code needs to set the lun bits
>> >> if the SCSI level is <= 3.
>> >Not '<=', but '<'. A.
>> Well, SCSI-3 did not include this new feature in the beginning,

>Define "beginning." First draft or first ratified specification? Can you
>really confirm that 3 most significant bits of second byte of command
>block were still LUN in first ratified document?

Except for SCSI-1, I know of no SCSI standard that has ever been used
from aproved versions.

The background is that getting a "final" versions costs money while
the drafts are free. Also drive manufacturers are most often faster than
the standard... SCSI-3 is now in progress since more than 4 years.
I am sure that the LUN bits have not been redifined in the first version.

>> so
>> any firmware that enforces the lun field to be zero for SCSI-3 is broken.

>No, it's not. "Recipients *may* check reserved bits, bytes, words or
>fields for zero values and report errors if non-zero values are

As you cannot check whether a drive supports an early SCSI-3 draft or a later
one, this incompatible change cannot be used before SCSI-4


 EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
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