Table 10.Data Transfer Speed - Hitachi T7K250 - Deskstar - Hard Drive Specifications

4.5.4 Data transfer speed
Table 10: Data transfer speed
Data transfer speed
Disk-Buffer transfer (Zone 0)
Instantaneous - typical
Sustained - read typical
Disk-Buffer transfer (Zone 29)
Instantaneous - typical
Sustained - read typical
Buffer - host (max)
• Instantaneous disk-buffer transfer rate (Mbyte/s) is derived by the following formula:
512 (Number of sectors on a track) (revolutions per second)
Note: The number of sectors per track will vary because of the linear density recording.
• Sustained disk-buffer transfer rate (Mbyte/s) is defined by considering head/cylinder change time for
read operation. This gives a local average data transfer rate. It is derived by the following formula:
(Sustained Transfer Rate) = A/(B+C+D)
where
• Instantaneous buffer-host transfer rate (Mbyte/s) defines the maximum data transfer rate on the
AT Bus. It also depends on the speed of the host.
The method of measurement is given in 4.5.5, "Throughput" on page 19.
Mbytes/sec
79.6
67.8
38.7
32.9
133
A = 512 (number of data sectors per cylinder)
B = (number of Surfaces per cylinder – 1) (head switch time)
C = cylinder change time
D = (number of surfaces) (time for one revolution)
Deskstar T7K250 Hard Disk Drive Specification
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