IBM IC35L018UCDY10, Specifications

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as untagged commands with a MESSAGE REJECT message being returned immediately after the
queue tag is received by the drive.
11.4 Command reordering
Command reordering function is supported under tagged command queuing enabled (DQue, Mode Page
A, is set to zero). The reorder feature reorders READ/WRITE commands in order to minimize seek time
between commands. This function will improve total throughput of the drive.
11.5 Concurrent I/O Process
The Concurrent I/O process when multiple I/O processes are active (not queued) on the same logical unit
at the same time. The drive may start the data phase of an I/O process while another I/O process is not
completed. The following I/O processes are allowed to execute concurrently:
!
Unlinked and untagged REQUEST SENSE, INQUIRY or REPORT LUNS command during execution
of other commands.
!
One of the following commands can be executed while another one or the same one of the following
commands is being executed, if those are untagged or simple tagged commands.
–
READ(6), READ EXTEND(10)
–
WRITE(6), WRITE EXTEND(10)
When an I/O process ends in CHECK CONDITION Status, the drive enters the Contingent Allegiance
Condition and other queued I/O processes from all initiators on the same logical unit will not reconnect and
will not complete the execution until the sense data is cleared. See Section 11.15, “Contingent allegiance
Condition,” on page 209 for details. If an I/O process (P-1) encounters an error while another I/O process
(P-2) is active, the drive returns CHECK CONDITION to P-1 and P-2. The drive may continue P-2 until its
convenient point to suspend, but may not send a Status. After the initiator clears the Contingent Allegiance
condition, the drive will resume or terminate P-2 according to QErr bit of Control mode page.
If the drive gets an error on P-1 before suspending the execution of P-2, it will keep the sense data
separately from the sense data for P-1. The sense data for P-2 will be set after the Contingent Allegiance
condition caused by P-1 is cleared.
11.6 Back to Back Write
Back to Back Write allows plural write commands requesting sequential LBA's to be written without losing
a motor revolution.
Ultrastar 146Z10 hard disk drive specifications
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