Question on Disc Type field value in MMC4

Bmcferrin at aol.com Bmcferrin at aol.com
Mon Jan 5 14:50:18 PST 2004


* From the T10 Reflector (t10 at t10.org), posted by:
* Bmcferrin at aol.com
*

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Dear Katata-san,
I apologize for the delayed response.  I have requested Kohda-san to
change my address on the MtFuji reflector.

MMC-3 states:
"The DoOpc bit, when set to one, indicates the Logical Unit shall
perform an OPC operation to set the OPC values for the current speed.
These OPC values shall become current. Parameter List length should be
set to zero."

The phrase "should be set to zero" means that any value is permitted,
but zero is preferred.  Greg Fry preferred "ignored".  No one objected
at the time.

The word "ignored" is a term that has been with us for a long time...

SPC3R15 states:
3.3.2 ignored: A keyword used to describe an unused bit, byte, word,
field or code value. The contents or value of an ignored bit, byte,
word, field or code value shall not be examined by the receiving SCSI
device and may be set to any value by the transmitting SCSI device.

With respect to the potential error for invalid OPC parameters, you are
right.  The device should be premitted to post an error.  I shall change
that in MMC4R02G.

I do not remember the discussion that you say we had.  This concerns me,
so I have requested that a regular MMC attendee act as secretary in the
future so that I do not forget these things in the future.

Thank you for your comments.  Please do not hesitate to send any other
comments that you may have.

Kind Regards,
Bill McFerrin



Ai-san,

I have found too many troubles of MMC4r02f to remember them. I forget
many
of them now except Send OPC Info command.

--- MMC3r10g ---
The DoOpc bit, when set to one, indicates the Logical Unit shall perform
an
OPC operation to set the OPC values for the current speed. These OPC
values
shall become current. Parameter List length should be set to zero. When
the
bit is set to zero, the Logical Unit sets OPC values to those sent in
the
Parameter List.
--- MMC4r02f ---
If DoOpc is set to one, the Logical Unit shall perform an OPC operation
to
set the OPC values for the current speed. These OPC values shall become
current. When DoOpc is set to one, the Parameter List Length field is
ignored.
If DoOpc is set to zero, the Logical Unit shall transfer the Parameter
List
and attempt to set OPC values to those in the Parameter List.
---------------

"Ignored"! what does it mean in ISO/ANSI standard?
According to Bill, this is perfect definition and technically correct
completely.

Fuji has following sentence.
--- Fuji ---
If an illegal OPC table entry is detected, the logical unit shall report
CHECK CONDITION Status, 5/26/00 INVALID FIELD IN PARAMETER LIST.
------------

If a software sends nonsense data to device has a right to reject it. If
device does not have capability to report OPC Information via Read Disc
Information command, device has a right to refuse this command with
DoOPC=0.

MMC4 (Bill) says that be silent.

Best regards,

Keiji Katata
PIONEER CORP.






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Dear Katata-san,
 I apologize for the delayed response.  I have requested Kohda-san = to change my address on the MtFuji reflector.
 
MMC-3 states:
 "The DoOpc bit, when set to one, indicates the Logical Unit shall = perform an OPC operation to set the OPC values for the current speed. = These OPC values shall become current. Parameter List length should be = set to zero."
 
The phrase "should be set to zero" means that any value is permitted, = but zero is preferred.  Greg Fry preferred "ignored".  No one = objected at the time.
 
The word "ignored" is a term that has been with us for a long = time...
 
SPC3R15 states:
 3.3.2 ignored: A keyword used to describe an unused bit, byte, word, = field or code value. The contents or value of an ignored bit, byte, = word, field or code value shall not be examined by the receiving SCSI = device and may be set to any value by the transmitting SCSI device.
 
With respect to the potential error for invalid OPC parameters, you are = right.  The device should be premitted to post an error.  I = shall change that in MMC4R02G.
 
I do not remember the discussion that you say we had.  This = concerns me, so I have requested that a regular MMC attendee act as = secretary in the future so that I do not forget these things in the = future.
 
Thank you for your comments.  Please do not hesitate to send any = other comments that you may have.
 
Kind Regards,
 Bill McFerrin
 
I have found too many troubles of MMC4r02f to remember them. I forget = many
 of them now except Send OPC Info command.
 
--- MMC3r10g ---
 The DoOpc bit, when set to one, indicates the Logical Unit shall = perform an
 OPC operation to set the OPC values for the current speed. These OPC = values
 shall become current. Parameter List length should be set to zero. When = the
 bit is set to zero, the Logical Unit sets OPC values to those sent in = the
 Parameter List.
 --- MMC4r02f ---
 If DoOpc is set to one, the Logical Unit shall perform an OPC operation = to
 set the OPC values for the current speed. These OPC values shall = become
 current. When DoOpc is set to one, the Parameter List Length field = is
 ignored.
 If DoOpc is set to zero, the Logical Unit shall transfer the Parameter = List
 and attempt to set OPC values to those in the Parameter List.
 ---------------
 
"Ignored"! what does it mean in ISO/ANSI standard?
 According to Bill, this is perfect definition and technically = correct
 completely.
 
Fuji has following sentence.
 --- Fuji ---
 If an illegal OPC table entry is detected, the logical unit shall = report
 CHECK CONDITION Status, 5/26/00 INVALID FIELD IN PARAMETER LIST.
 ------------
 
If a software sends nonsense data to device has a right to reject it. = If
 device does not have capability to report OPC Information via Read = Disc
 Information command, device has a right to refuse this command with
 DoOPC=3D0.
 
MMC4 (Bill) says that be silent.
 
Best regards,
 
Keiji Katata
 PIONEER CORP.
 





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