Hitachi 7K250 Specifications - Page 32

Instantaneous buffer-host transfer rate Mbyte/s defines the maximum data transfer rate on - deskstar 250gb hard drive

Page 32 highlights

4.4.4 Data transfer speed Table 11: 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) 250GB model (Mbytes/s) 72.1 61.4 34.9 29.7 100 • 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 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) • 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 4.4.5, "Throughput" on page 19. Deskstar 7K250 Hard Disk Drive Specification 18

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Deskstar 7K250 Hard Disk Drive Specification
18
4.4.4
Data transfer speed
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
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)
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 4.4.5, “Throughput” on page 19.
Table 11: Data transfer speed
Data transfer speed
250GB model
(Mbytes/s)
Disk-Buffer transfer (Zone 0)
Instantaneous - typical
72.1
Sustained - read typical
61.4
Disk-Buffer transfer (Zone 29)
Instantaneous - typical
34.9
Sustained - read typical
29.7
Buffer - host (max)
100