Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
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4.5.2 Drive ready time
Table 9:Drive ready time
4.5.3 Spindle stop time
Table 10:Spindle stop time
The period from power off to the complete stop of the rotating spindle is categorized as 'operating'. The Operating shock crite-
ria apply during this period. Refer to section 12.3, “Operating shock” on page 41.
4.5.4 Data transfer speed
Table 11:Data transfer speed (sector size 512 Byte case)
Notes:
• Instantaneous disk-buffer transfer rate is derived by: (Number of sectors on a track) x 512 x (revolutions/sec)
• For this table, '1 MB / Sec' should be interpreted as 1,000,000 bytes per Second.
• The number of sectors per track will vary by zone because of the linear density recording.
• Sustained disk-buffer transfer rate is the average rate measured while transferring multiple cylinders of data. It dif-
fers from the instantaneous transfer rate because of the time required to change tracks (Cylinder skew and Head
skew). In addition, time is added for the occasional missed transfer.
4.5.5 Buffering operation (read ahead/write cache)
This hard disk drive has a buffer for read ahead (see Segmented Caching, page331).
Model Typical (sec) Maximum (sec)
450 GB Model 21.0 29.9
300 GB Model 21.0 29.9
Model Typical (sec) Maximum (sec)
450 GB Model 11.0 20
300 GB Model 11.0 20
Description
Disk-buffer transfer
Typical (MB / Sec)
Zone Model Read Write
Instantaneous 0 450 GB 179.7 179.7
0 300 GB 152.1 152.1
Measured typical values for sustained disk-
buffer tranfer rate 0 450 GB 160.0 155.8
0 300 GB 135.0 131.5
Instantaneous 22 450 GB 112.3 112.3
17 300 GB 110.6 110.6
Measured typical values for sustained disk-
buffer tranfer rate 22 450 GB 99.9 97.3
17 300 GB 98.2 95.6