Rob,
Prior to ATA/ATAPI-6 a drive could comply with the standard by reading data from the buffer on a Read Verify command. This issue was addressed by a change to the command description that required the drive to read from the media when servicing a Read Verify command. The command description for Read Verify in ATA/APAPI-6 and above reads as follows:
This command is identical to the READ SECTOR(S) command, except that the device shall have read the data from the media, the DRQ bit is never set to one, and no data is transferred to the host.
Regards,
Steve Livaccari
Hard Drive Engineering
IBM Global Procurement
Internet: [EMAIL PROTECTED]
Phone (919) 543.7393
| "Elliott, Robert (Server
Storage)" <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED] 05/18/2006 05:41 PM |
|
The T10 SCSI to ATA Translation (SAT) standard needs a reliable way to spin up a drive to translate a SCSI START STOP UNIT command with START=1.
VERIFY is specified in revision 8, but there is concern the drive might read data from a read cache and not bother spinning up. Is that concern valid?
READ could be used, but again the drive might read from a cache (unless it the SATA READ FPDMA QUEUED command can be used, which offers an FUA bit).
IDLE (IMMEDIATE) seems like another candidate. Although Idle is in-between Active and Standby modes, it does not allow 30 s recovery time like Standby and Sleep, implying that the drive is spun up. Is this guaranteed?
Would this be the best translation?
1. IDLE IMMEDIATE; then
2. VERIFY to any LBA
--
Rob Elliott, [EMAIL PROTECTED]
Hewlett-Packard Industry Standard Server Storage Advanced Technology
https://ecardfile.com/id/RobElliott
