[T10] SSC-5 and inclusion of D_BOPC bit in commands that support IMMED bit

Tim Jones tjmac at tolisgroup.com
Thu Aug 18 21:23:40 PDT 2016


Thanks, Curtis.  I’ve pushed this upstream to the vendors as it can truly cause unexpected reactions on the part of users who like to “watch the grass grow” and notice differences between incumbent LTO-5/6 drives and new LTO-7 drives.

Tim


> On Aug 18, 2016, at 1:51 PM, Ballard, Curtis C (HPE Storage) <curtis.ballard at hpe.com> wrote:
> 
> The functionality you are referring to is vendor specific and as such as you have observed is not specified in SSC-5.  You may want to discuss that with the drive vendor. If they wish to contribute that functionality and there is general industry value we could define equivalent functionality in SSC-5 but we wouldn’t be able to document the vendor specific version.
>  
> Curtis Ballard
> Hewlett Packard Enterprise
> SSC-5 Editor
>   <>
> From: t10-bounces at t10.org <mailto:t10-bounces at t10.org> [mailto:t10-bounces at t10.org <mailto:t10-bounces at t10.org>] On Behalf Of Tim Jones
> Sent: Wednesday, August 17, 2016 12:35 PM
> To: t10 at t10.org <mailto:t10 at t10.org>
> Subject: [T10] SSC-5 and inclusion of D_BOPC bit in commands that support IMMED bit
>  
> Hi Folks,
>  
> In dealing with modern LTO-6 and LTO-7 drives, we’ve noted (specifically for IBM devices) that commands set with the IMMED bit unset have started to act as if the bit is set with what should be long running tape motion (SPACE, LOCATE, etc.) commands returning from the device server immediately.
>  
> After digging through execution logs and discussing this with our HPE tech team members, we have finally uncovered the new D_BOPC bit that can affect the expected results of such commands.  This is not mentioned in the current SSC-5 draft rev 02b, dated Jul 1, 2016.
>  
> I recommend that the D_BOPC information be added and that all commands utilizing the IMMED bit be updated to include a reference to the affect of the D_BOPC bit on those commands.
>  
> Thanks for your consideration,
> Tim
> --
> Tim Jones                                            tjmac at tolisgroup.com <mailto:tjmac at tolisgroup.com>
> President/CTO                                    http://www.tolisgroup.com <http://www.tolisgroup.com/>
> TOLIS Group, Inc.
> 480-505-0488 x227                             480-505-0492 (fax)
> <image001.png>
> BRU ... Because it's the RESTORE that matters
>  

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