SSD EOL Write Protect query

Mike Berhan mikeb at bustrace.com
Wed Jan 15 15:27:54 PST 2014


* From the T10 Reflector (t10 at t10.org), posted by:
* Mike Berhan <mikeb at bustrace.com>
*
The SBC-3r36 specification has a "Write Protection" section which states
that write protection is controlled by one of the following:
a) the user of the medium through manual intervention (e.g., a mechanical
lock on the SCSI target device);
b) hardware controls (e.g., tabs on the medium's housing); or
c) software write protection
For hardware write protection, it also states:
"Hardware write protection results when a physical attribute of the SCSI
target device or its medium is changed to specify that writing shall be
prohibited. Changing the state of the hardware write protection requires
physical intervention, either with the SCSI target device or its medium."
I cannot find a discussion of the drive putting itself into a write protect
state without manual or software intervention.	For example, an SSD that is
approaching its end of life might be running out of reserved free blocks and
will put itself into a write protect state.  If a drive fails this state, I
could see writes failing with returned sense data of:
07h 27h 05h (Data Protect - Permanent write protect)
Now to my question.  If a drive enters, on its own, this write protect
state, has it also entered a unit attention condition?	I'm assuming it
should.  If it has, what is the unit attention that should be returned to be
SBC-3 compliant?
Thanks in advance.
Mike
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