Obsolete mixed command and data, mixed data and response

Bob Snively Bob.Snively at Ebay.Sun.COM
Wed Nov 18 12:56:59 PST 1998

* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
* Bob Snively <Bob.Snively at Ebay.Sun.COM>

Sorry Doug, I really have no nefarious agenda here.  The function is
poorly, incompletely, and ambiguously documented, which is true of most
of the "creeping elegance" features that we have allowed into our 
documents and which I have, with far too little success, attempted to
stamp out every time I have found a good target.  Their documentation is
poor because nobody has tried to implement them and been forced to ask
the hard question, "what does that really mean?".  

To make a product interoperable, robust, low in cost, easy to test, and
high in performance requires that the standards that define the interface
be simple and clean.

If this particular element of creeping elegance has struck your company's
fancy as being particularly useful, then I would expect to receive
a "please do not remove this function" message together with a dozen
pages of comments and criticisms so that we can document it 
unambiguously in the standard.  This in fact is exactly what has happened
with most "creeping goodness" features that achieved the coveted goodness label,
including such examples as tagged queueing, arbitrated loop, concise 
exchange status ELS's, persistent reservations, high speed parallel 
transfers, Command Reference Numbers, and FCP_CONF.


> I agree with Gene that the recent wholesale effort to eliminate
> "obsolete" or "unused" functions from established standards is an
> objectionable practise. For one thing, it puts yet another burden on all
> users of the standards because now we need to keep track on a monthly
> basis to make sure that something we're using doesn't disappear. For
> another thing, the method used seems to have some of the flavor of a
> fishing expedition. What if I'm using this and don't want to tell you?

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