Wording issue with SPI-4 rev. 8
Robert.Elliott at COMPAQ.com
Fri Dec 28 14:45:31 PST 2001
* From the T10 Reflector (t10 at t10.org), posted by:
* "Elliott, Robert" <Robert.Elliott at compaq.com>
I agree that the two tables conflict - when the offset is 00h, are the
transfer period factor and protocol options ignored or invalid?
In Rev 7 and in 01-131r4, table 11 listed the transfer period factor as
00h - FFh in this case, implying it is completely ignored. Rev 8
changed the 00h to 0Ah but still has a range. Some letter ballot
comment must have asked for the 0Ah change.
The protocol option bits, however, did not have "0 or 1" to indicate
they are ignored. They should all (except QAS_REQ) be "0 or 1" if we
want them ignored. If we want them cleared, the table 7 change you
suggest makes sense.
Remember that QAS is supported without Information Units. Non-IU
targets may participate in QAS generated by other targets; they just
won't generate QAS_REQUEST messages themselves. Thus there are two rows
in table 11 for QAS and non-QAS asynch modes.
Rob Elliott, Compaq Server Storage
Robert.Elliott at compaq.com
> -----Original Message-----
> From: Gerry.Houlder at seagate.com [mailto:Gerry.Houlder at seagate.com]
> Sent: Friday, December 28, 2001 3:10 PM
> To: t10 at t10.org
> Cc: Paul.Wasielewski at seagate.com
> Subject: Wording issue with SPI-4 rev. 8
> * From the T10 Reflector (t10 at t10.org), posted by:
> * Gerry.Houlder at seagate.com
> I am looking at SPI-4, revision 8. The way I read it, there
> seems to be a
> conflict between the footnote in Table 7 in section 220.127.116.11
> and the last
> two sentences in section 4.12.5 (just prior to Table 11).
> Table 11 lists the "Valid negotiable field combinations". The two
> sentences that precede it say:
> "Only the combinations in table 11 shall be allowed. All other
> combinations of the listed fields are reserved."
> The first data line in Table 7 says that a REQ/ACK offset of 00h:
> "Specifies asynchronous transfer agreement. (superscript: a) "
> The (superscript: a) superscript footnote says:
> " (superscript: a) Transfer period factor and protocol
> options other
> than QAS_REQ shall be ignored."
> I see two problems with the footnote:
> (1) It says that "protocol options other than QAS_REQ .."
> have a certain
> handling. I believe that QAS_REQ should have the same
> handling as the other
> protocol options because QAS isn't allowed with asynchronous
> transfers. It
> is only allowed with Information units, which are never asynchronous.
> (2) It says that ".. shall be ignored." Ignore suggests that
> the responding
> device can send the same values back to the initiating
> device. However the
> wording with table 11 say "only the combinations in table 11
> are allowed".
> This suggests that the responding device must clear the
> invalid bits in the
> responding message or it would be transmitting a reserved combination.
> I suggest rewording the footnote to say:
> The Transfer period shall be ignored and the protocol
> options shall be
> Does anyone else have an opinion on this?
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