AER functionality

Elliott, Robert Robert.Elliott at
Thu Mar 28 15:32:34 PST 2002

* From the T10 Reflector (t10 at, posted by:
* "Elliott, Robert" <Robert.Elliott at>
I think the INQUIRY AERC bit needs rewording.

"The asynchronous event reporting capability (AERC) bit indicates that 
the target supports the asynchronous event reporting capability as 
defined in SAM-2. The AERC bit is qualified by the PERIPHERAL DEVICE 
TYPE field as follows:
a) Processor device-type definition: An AERC bit of one indicates 
   that the processor device is capable of accepting asynchronous event 
   reports. An AERC bit of zero indicates that the processor device
   does not support asynchronous event reports; or
b) All other device-types: This bit is reserved.

Details of the asynchronous event reporting support are protocol specific."

I think the intention is to identify which processor devices can receive
AERs (with SEND commands), not which target devices can generate AERs 
(by whatever method the protocol supports).  The latter can be determined 
by checking if any of the three Control mode page AER bits are changeable.

A processor device type probably cannot itself generate AERs, because it
does not define support for the Control mode page.
Rob Elliott, Compaq Server Storage
Robert.Elliott at


> -----Original Message-----
> From: Ken Craig [mailto:kcraig at]
> Sent: Thursday, March 28, 2002 5:01 PM
> To: t10 at
> Subject: AER functionality
> * From the T10 Reflector (t10 at, posted by:
> * "Ken Craig" <kcraig at>
> *
> I have a question concerning AER functionality.  My reference points
> are:
> SPC-3 revision 4, 12 February 2002
> SAM-2 revision 22, 24 Feb, 2002.
> The INQUIRY command says that reporting AER functionality is reserved
> for all device types except a processor device and the 
> Control Mode page
> has the fields to control how/when the reporting is done.
> The descriptions that describe the examples in SAM-2, section,
> seem to describe events that could occur in non-processor 
> device types.
> For instance the explanation for example a talks about a device with a
> write cache.  If this was a disk and it had reported itself as a disk
> device
> type in the INQUIRY data how could it send an AER based on the
> definition in SPC-3?
> My question is "Is the description in the INQUIRY command concerning
> which device types can report supporting AER functionality 
> wrong or can
> the settings in the Control Mode page enable AER functionality even
> though a non-processor device type has been reported which means the
> AER bit in the INQUIRY data was set to 0?"
> Thanks,
> Kenneth Craig
> *
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