Very old SMC typo - Suggested Fix

Terry Spear terrys at boulder.mntgte.lockheed.com
Fri Jun 21 10:20:54 PDT 1996


* From the SCSI Reflector, posted by:
* Terry Spear <terrys at boulder.mntgte.lockheed.com>
*
>The diagram illustrating the Media Changer Mode Select Device Capabilities
Page has an inconsistency in it that dates back to the SCSI-2 standard.
>
>Reference p60 of SMC rev 05.
>
>The Page Length field value is 12H.
>
>The page length shown in the diagram is 0EH.
>
>A brief survey of implementations show that that many assume the page
length value of 12H is correct and add 4 reserved bytes to the end of the
data structure: Exabyte, Breece Hill, MountainGate. Some chose to interpret
this inconsistency by changing the page length value to 0EH: DEC->Quantum.
>
>Please lets remove this inconsistency if possible before going to print
with SCSI-3.
>

I suggested the following change to prevent creating non-conformance with
existing devices: Change Table 27 by adding an optional 4 byte vendor
specified field after byte 15 and redefine the page length value as 0EH if
the optional field is present, 12H otherwise.

==============================================================
Terry L. Spear				MountainGate, Inc.
terrys at boulder.mntgte.lockheed.com	Lockheed Martin
303-413-8544				6287 Arapahoe Road
303-413-8593(fax)			Boulder, CO 80303





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