Seagate BARRACUDA 2LP, Руководство по эксплуатации продукта

Страница: 21 / 102

Barracuda 2LP Product Manual, Rev. D 11
5.0 Performance characteristics
This section provides performance-related characteristics and features of
Barracuda 2LP drives.
5.1 Internal drive characteristics
ST31250 ST32550
Drive capacity, Mbytes unformatted 1,205.3 2,541.3
Read/write data heads, 5 11
maximum (physical)
Bytes per track, average bytes 64,160 64,160
Bytes per surface, Mbytes unformatted 232.4 231.03
Cylinders/tracks per surface, 3,711 3,510
user accessible
Tracks per inch 4,048 4,048
Bits per inch 73,820 72,680
Servo heads 1 1
Internal data rate per physical head, 47.5 to 72.0 49.4 to 72.0
Mbits/sec, variable with zone
Disc rotation speed 7,200
±
0.5% 7,200
±
0.5%
Average rotational latency, msec 4.17 4.17
5.2 SCSI seek performance characteristics
This section first describes the thermal calibration algorithms used by ASA
I and ASA II download code. Section 5.2.1 provides actual seek times and
section 5.2.2 provides drive format execution times.
Refer to Table 22 in Section 11.10 and to the
SCSI-2 Interface Product
Manual (part number 77738479) for additional timing details.
ASA I thermal calibration
All performance characteristics assume that automatic adaptive thermal
compensation is not in process when the drive receives the SCSI command.
Automatic adaptive thermal compensation will not interrupt an active SCSI
command. If adaptive thermal compensation is in process when a SCSI
command is received, the command is queued until compensation com-
pletes. When compensation completes for the head, the first queued SCSI
command executes, and the drive continues compensation for the remaining
heads.
The above procedure continues until compensation for all heads has
completed, or until 10 minutes have elapsed. The drive initiates an automatic
adaptive thermal compensation cycle once on power-up before completing
its initialization sequence, once after 1 minute from the end of initialization,
and then once approximately every 10 minutes. Automatic thermal com-
pensation occurs at other times but should be transparent to the user (e.g.,