SES SSC-2 Enclosure Services Management mode page and tape drives

[Elliott, Robert (Server Storage)]

* From the T10 Reflector (t10 at t10.org), posted by:
* "Elliott, Robert (Server Storage)" <Elliott at hp.com>
*
SES revision 8b defines Enclosure Services Management mode page 14h.
This page does not show up in the SPC-3 mode page table, but it's
applicable to any device hosting a SCSI enclosure services device
and to standalone SCSI enclosure service devices.

SES describes a problem with this page and tape drives:

"The page code selected for the enclosure services management
page overlaps with the medium partition 04h page defined for 
tape drives, as shown in ANSI X3.301. An SES device shall not 
be embedded in a tape drive. Tape drives shall not use the 
timed completion function specified by the enclosure services 
management page. Devices other than enclosure services devices 
and tape devices may implement this page and use the timed 
completion function if their interface to the enclosure
services process allows this capability."

One obvious typo: 04h should be 14h.

For SES-2:
1. Should tape drives be allowed to host SES devices?

2. Should this mode page continue to exist or become obsolete?
It only provides a "timed completion" feature instructing the
device server that it need not fetch the requested status page
for n * 100 ms after receiving the RECEIVE DIAGNOSTIC RESULTS
command.

3. If tape drive support is worthwhile and the mode page still 
exists, can this mode page remain inaccessible from tape
drives or should we define an alternate page code for access
through a tape drive?  This code would need to be in SSC-2.

--
Rob Elliott, elliott at hp.com
Industry Standard Server Storage Advanced Technology
Hewlett-Packard


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