Thanks. Is there anything anywhere
that states that modifying a mode parameter shall not or should not cause
a POR?
Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/
"Penokie, George"
<George.Penokie@lsi.com>
08/06/2008 01:54 PM
To
Kevin D Butt/Tucson/IBM@IBMUS, "t10@t10.org"
<t10@t10.org>
cc
Subject
RE: Mode Parameter changes and when
they take effect
Kevin,
There are some ways that an
action requested in a command may be deferred. Those are:
1) when the command supports
the IMMED bit (MODE SENSE and MODE SELECT do not)
2) if the command has explicit
rules defined as to when a specific action is to take place (Mode parameter block descriptor in the mode page parameters is an example
of that)
3) if a specific page has
explicit rules defined as to when a specific value is to take affect. (I
know of none but I did not do an extensive search)
If the mode parameters
you are referring to in your note do not have explicit rules stating that
are not required to take effect until a POR occurs then SAM requires them
to be valid on completion of the MODE SELECT command. In other words there
is nothing special about the MODE SELECT command that allows an implementation
to treat mode pages any different that any other kind of parameter data.
Bye for now,
George Penokie
LSI Corporation
3033 41st St. NW
Suite 100
Rochester, MN 55901
507-328-9017
george.penokie@lsi.com
From: owner-t10@t10.org [mailto:owner-t10@t10.org]
On Behalf Of Kevin D Butt
Sent: Wednesday, August 06, 2008 2:09 PM
To: t10@t10.org
Subject: Mode Parameter changes and when they take effect
I have a question related to Mode Parameters. I have searched SPC-4
(and earlier SPC versions) and cannot find guidance about when the changes
to mode parameters take effect. This concern is related to configuration
settings and differences in expectations of various vendors.
Vendor 1 claims that any change to a mode parameter shall become effective
immediately and should not cause a device to reboot.
Vendor 2 claims that changes to some mode parameters require a reboot before
they can be accomplished. As such the device automatically performs
a POR on completion of the Mode Select that changes one or more of these
parameters.
Vendor 3 also claims that changes to some mode parameters require a reboot
before they can be accomplished. This device,however, requires that
an outside entity send a command to force the device to perform a POR.
The new values of the mode parameters are not in effect until after
the POR.
In another form of when do parameters take effect, the requested change
to the format (or density) does not occur until a subsequent command (e.g.,
a Format, a Write from BOT, etc.).
Is there any guidance in SPC?
Thanks,
Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/