SSC-4: Locate to EOD of partition x

Kevin D Butt kdbutt at us.ibm.com
Tue Jan 19 12:52:04 PST 2010


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Tim,
Space(6) works great as long as you are only spacing inside a singe 
partition.  Or if you locate to a different partition then space.  The 
scenario I am trying to solve is from partition X issue one command and 
arrive at EOD of partition Y with no Check Condition.
Thanks,
Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt at us.ibm.com
http://www-03.ibm.com/servers/storage/ 
From:
Tim Jones <tjmac at tolisgroup.com>
To:
Kevin D Butt/Tucson/IBM at IBMUS
Date:
01/19/2010 01:20 PM
Subject:
Re: SSC-4: Locate to EOD of partition x
Kevin,
I'm a bit confused with your question since we use SPACE(6) with success 
on all current drives in both single partition and multipartition 
scenarios.
Are we just lucky here, or am I misunderstanding what you are asking 
about?
Tim
On Jan 19, 2010, at 12:03 PM, Kevin D Butt wrote:
Tapeheads, 
I have been asked if there is currently a method to locate to the EOD of a 
specified partition (e.g., change partition and go to EOD) without a Check 
Condition.  In my research I see no method to do this in a single command. 
 If you are currently in partition x you can Space EOD and not get a check 
condition.  But, if the current position is in partition y you must use a 
locate to change partition.  You can specify a locate to a very large 
number and - depending on implementation - may or may not find yourself at 
EOD after a Check Condition. 
I was also asked if the SSC-4 WG would like to define a method to 
accomplish this. 
If we believe it is useful, and I do, I would suggest we add a bit to the 
Locate(16) command that specifies EOD is the destination of the Locate 
command.  Then we could change partition and locate to EOD in one command 
without getting a Check Condition.  I thought that would be better than 
adding EOD as a Dest_type value as I view that as qualifying the Logical 
Identifier field. 
What do you think? 
Thanks, 
Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt at us.ibm.com
http://www-03.ibm.com/servers/storage/ 



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