Cross-reference on MATED Signals in SPI-3

Gene_Milligan at notes.seagate.com Gene_Milligan at notes.seagate.com
Fri Apr 23 14:50:45 PDT 1999


* From the T10 Reflector (t10 at symbios.com), posted by:
* Gene_Milligan at notes.seagate.com
*
SFF 8451 is a treatise by Bill Ham. I think the document you need to refer
to for the SCA-2 signals is SFF 8067. SFF 8067 includes Table 6-6 which
defines the motor start controls. Three cases are defined plus a very
confusing reserved case 4. The clear cases are: spin with power on, spin
when SCSI Start command received, and spin up delayed from power base upon
12 times the ID in seconds. It corresponds to Table C.4. The offending text
you cite is 6.4.9.3 in SFF 8067.

Regarding <<a) The SCSI device may optionally perform a spin-down
operation. This option is controlled by a MODE SELECT operation.>>

     I am not able to provide 100% or even 10% recall on this. Perhaps Bob
Snively can. But it could be a vague reference to the Power condition page.
A court would find that the Power condition page does do what (a) states.

Regarding <<b) The SCSI device may optionally transfer any cached
information to the media. This option is controlled by a MODE SELECT
operation.>>

     My recall is no better with this one. But in a court it can be proved
that the Caching page fulfills the (b) statement. The reasoning is somewhat
circuitous, fitting a court, in that all designers in their right mind will
flush the write cache if they are warned that power is going away. With the
Cache page write caching may be disabled depriving the drive of any
information to flush.

Gene







gop at us.ibm.com on 04/22/99 02:09:31 PM

To:   t10 at Symbios.COM
cc:    (bcc: Gene Milligan)

Subject:  Cross-reference on MATED Signals in SPI-3




* From the T10 Reflector (t10 at symbios.com), posted by:
* gop at us.ibm.com
*


SPI-3 annex C provides the physical descriptions and usage guidelines for
the SCA-2 see Single Connector Attachments (SCA-2), EIA-700A0AE and SCA-2
Unshielded Connections, SFF-8451. This was originally an SFF document but
was incorporated into SPI.

A question has come up regarding a cross-reference contained in that annex
which I cannot answer.  The question is what MODE SELECT operation is being
referenced in the following two statements that come from SPI-3 rev 4
section C.1.7.3.

a) The SCSI device may optionally perform a spin-down operation. This
option is controlled by a MODE SELECT operation.
b) The SCSI device may optionally transfer any cached information to the
media. This option is controlled by a MODE SELECT operation.

It is not at all obvious as to what is been cross-referenced. If anyone
knows what is being cross-referenced  please let me know. If no one can
tell me specifically what is being cross-referenced I plan on asking the
SCSI committee to delete those cross references.

Bye for now,
George Penokie

Dept PPV  114-2 N212
E-Mail:    gop at us.ibm.com
Internal:  553-5208
External: 507-253-5208   FAX: 507-253-2880




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