Comments on Partial Medium Load (T10/99-347r1)
ljesion at us.ibm.com
ljesion at us.ibm.com
Wed Dec 22 16:11:23 PST 1999
* From the T10 Reflector (t10 at t10.org), posted by:
* ljesion at us.ibm.com
I have the following comments on the proposal for SPC support of partial
loading and unloading (347r1):
In Section 3.3.1, the following statement regarding partial load states
seems incorrect: "In both cases, the device can be addressed, so a sense
key of Not Ready is inappropriate according to SPC". What then should be
reported for subsequent medium-access commands once the proposed Unit
Attention has been reported? Not Ready seems most appropriate, and there
is at least one related precedent.
A "Medium Loadable" position will be equivalent to an unloaded position on
some tape drives, who must comply with the following from SSC. "Following
successful completion of an unload operation, the device server shall
return CHECK CONDITION status with the sense key set to NOT READY for all
subsequent medium-access commands until a new volume is mounted or a load
operation is successfully completed." I believe most such tape drives
handle this precedent "Medium Loadable" position with NOT READY sense of
3Ah/00h (MEDIUM NOT PRESENT) reported for all medium-access commands except
a Load command.
I would like to propose that the subject document include guidance on Not
Ready conditions to be reported for the intermediate states. One
possibility, based on the above precendent, might be as follows:
3Ah/10h Medium Loadable
3Ah/11h Medium Auxiliary Memory Accessible
Alternatively, existing ASC/ASCQ's of 3Ah/00h (MEDIUM NOT PRESENT) and
04h/02h (LOGICAL UNIT NOT READY, INITIALIZING CMD. REQUIRED) might also be
considered for the respective states.
Note also that specification of unique Not Ready sense might lead to
elimination of the need to specify new Unit Attention ASC/ASCQ's.
Lastly, an editorial comment: in section 2.2, item 3 in numbered list,
"standard Load" should be "standard Unload".
Lee Jesionowski, IBM Removable Media Storage Solutions
* For T10 Reflector information, send a message with
* 'info t10' (no quotes) in the message body to majordomo at t10.org
More information about the T10