"reserved" means what, according to t10

Peter Johansson PJohansson at acm.org
Mon Feb 3 13:49:46 PST 2003

* From the T10 Reflector (t10 at t10.org), posted by:
* Peter Johansson <PJohansson at ACM.org>
At 11:21 AM 2/3/2003 -0700, Pat LaVarre wrote:

>What do T10 folk think "reserved" does mean?

I concur with what Jim McGrath is saying and to give you another example, 
Pat, from SBP:

"reserved: A keyword used to describe objects (bits, bytes, quadlets, 
octlets and fields) or the code values assigned to these objects in cases 
where either the object or the code value is set aside for future 
standardization. Usage and interpretation may be specified by future 
extensions to this or other standards. A reserved object shall be zeroed 
or, upon development of a future standard, set to a value specified by such 
a standard. The recipient of a reserved object shall ignore its value. The 
recipient of an object defined by this standard as other than reserved 
shall inspect its value and reject reserved code values."

The key distinction is between reserved objects ("unused real estate") and 
reserved values in an already defined object (e.g., a command code). A 
legacy device that detects a reserved code value can't ignore the 
unsupported operation and return some sort of good status but must report 
the error to the originator.


Peter Johansson

Congruent Software, Inc.
98 Colorado Avenue
Berkeley, CA  94707

(510) 527-3926
(510) 527-3856 FAX

PJohansson at ACM.org

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