IBM IC35L040AVVN07-0 - 40GB IDE Deskstar 120GXP 7200RPM UATA-100..., Specifications, Page: 30 / 211

4.4.4 Data transfer speed
100 Buffer-Host (max)
23.2 Sustained - read typical
27.6 Instantaneous - typical
Disk-Buffer transfer (Zone 30)
48.0 Sustained - read typical
57.2 Instantaneous - typical
Disk-Buffer transfer (Zone 0)
120 GB model
(Mbyte/sec)
Data transfer speed
Figure 12. Data transfer speed
!
Instantaneous disk-buffer transfer rate (Mbyte/sec) is derived by the following formula:
512 (Number of sectors on a track) (revolution per second)
Note: The number of sectors per track will vary because of the linear density recording.
!
Sustained disk-buffer transfer rate (Mbyte/sec) 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/sec) 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 17.
Deskstar 120GXP hard disk drive specifications
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