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4.1.3
General performance characteristics
Minimum sector interleave
Maximum Internal data rate*
Sustained transfer rate
SAS Interface maximum instantaneous transfer rate
Logical block sizes
512 (default), 520, 524 or 528.
4096, 4160, 4192 or 4224.
Read/write consecutive sectors on a track
Flaw reallocation performance impact (for flaws reallocated at format time using the spare
sectors per sparing zone reallocation scheme.)
Average rotational latency
*Assumes no errors and no relocated logical blocks. Rate measured from the start of the first logical block transfer to or from the
host.
** MiB/s x 1.048 = MB/s
4.2
Start/stop time
The drive accepts the commands listed in the SAS Interface Manual less than 3 seconds after DC power has been applied.
If the drive receives a NOTIFY (ENABLE SPINUP) primitive through either port and has not received a START STOP UNIT command with the START bit
equal to 0, the drive becomes ready for normal operations within 30 seconds (excluding the error recovery procedure).
If the drive receives a START STOP UNIT command with the START bit equal to 0 before receiving a NOTIFY (ENABLE SPINUP) primitive, the drive
waits for a START STOP UNIT command with the START bit equal to 1. After receiving a START STOP UNIT command with the START bit equal to 1, the
drive waits for a NOTIFY (ENABLE SPINUP) primitive. After receiving a NOTIFY (ENABLE SPINUP) primitive through either port, the drive becomes
ready for normal operations within 30 seconds (excluding the error recovery procedure).
If the drive receives a START STOP UNIT command with the START bit and IMMED bit equal to 1 and does not receive a NOTIFY (ENABLE SPINUP)
primitive within 5 seconds, the drive fails the START STOP UNIT command.
The START STOP UNIT command may be used to command the drive to stop the spindle. Stop time is 23 seconds (maximum) from removal of DC
power. SCSI stop time is 23 seconds. There is no power control switch on the drive.
4.3
Prefetch/multi-segmented cache control
The drive provides a prefetch (read look-ahead) and multi-segmented cache control algorithms that in many cases can enhance system
performance. Cache refers to the drive buffer storage space when it is used in cache operations. To select this feature, the host sends the Mode
Select command with the proper values in the applicable bytes in page 08h. Prefetch and cache operations are independent features from the
standpoint that each is enabled and disabled independently using the Mode Select command; however, in actual operation, the prefetch feature
overlaps cache operation somewhat as described in sections 4.4.1 and 4.4.2.
All default cache and prefetch mode parameter values (Mode Page 08h) for standard OEM versions of this drive family are given in Table 9.
Seagate Exos X12 SAS Product Manual, Rev. C
1 to 1
2.7 Gb/s
103 to 249 MiB/s **
1200MB/s* per port
(dual port = 2400MB/s*)
Yes
Negligible
4.16ms
17
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