[nvmewin] SCSI to NVMe Mapping

[Guy Kendall]

Amber/Uma,



Sorry for the delayed response, I’m trying to get caught back up after
vacation.



First I should say that I am in no way leading the SCSI to NVMe translation
effort. I’m just the last person to contribute. The spec has been a
community effort with many companies contributing.



I didn’t contribute or modify the text you reference, but I’ll give you my
interpretation of it.



There are many commands that can be roughly translated between SCSI and
NVMe. However, there are also some SCSI commands that have no direct
translation to an NVMe command. In the case where there isn’t a direct
translation, the driver implementing the SCSI to NVMe translation layer
must respond to the SCSI commands in a way that will make a SCSI driver
sending these commands happy. I guess you can say that the driver has to
emulate these commands that can’t be translated. The translation spec does
indicate how you are supposed to respond to commands like Request Sense,
but the spec is certainly pretty light on detail. The SCSI to NVMe
translation spec serves the same purpose as the T10 SAT (SCSI to ATA
translation) spec, but the NVMe spec is much less mature. If you’re
interested, I think the NVMe community would welcome any proposals you have
to help update the NVMe translations to the same level as the ATA
translations.



Thanks,

Guy



*From:* Huffman, Amber [mailto:amber.huffman at intel.com]
*Sent:* Wednesday, August 06, 2014 1:19 PM
*To:* Uma Parepalli; technical at nvmexpress.org; nvmewin at lists.openfabrics.org;
info at nvmexpress.org
*Cc:* Guy Kendall (guy.kendall at avagotech.com)
*Subject:* RE: SCSI to NVMe Mapping



Hi Uma,



Guy, cc:ed, has been leading our efforts on SCSI to NVMe translation. I’d
suggest that you get together with Guy for 15 minutes to discuss and
determine whether anything needs to be added to the list of translation
enhancements in this area. I expect we’ll start looking at some
enhancements to the translation document in September, after revision 1.2
is done.



Thanks,

Amber



*From:* nvmewin-bounces at lists.openfabrics.org [
mailto:nvmewin-bounces at lists.openfabrics.org
<nvmewin-bounces at lists.openfabrics.org>] *On Behalf Of *Uma Parepalli
*Sent:* Tuesday, August 5, 2014 6:40 PM
*To:* technical at nvmexpress.org; nvmewin at lists.openfabrics.org;
info at nvmexpress.org
*Subject:* [nvmewin] SCSI to NVMe Mapping



Hi Amber/Peter/Kevin/Kwok and all,



The “NVM Express: SCSI Translation Reference” document doesn’t provide a
direct mapping for “REQUEST SENSE” but has the following Note:

“MODE SELECT(6), MODE SELECT(10), REQUEST SENSE and TEST UNIT READY
commands do not map 1-to-1 to NVM Express commands; a device driver should
translate as specified in the referenced sections.”



Could you please explain what would be the above commands are equal to in
the NVMe world?

I would like to hear from both NVMe forum and Windows Driver world.



Attaching the document since I know you (we) are all busy with Flash Memory
Summit J



Thank you,

Uma

Uma Parepalli

Cell: 408 805 9260

uma.parepalli at skhms.com

SK Hynix Memory Solutions Inc.

3103 North 1st Street, San Jose, CA



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