IBM DCAS-32160 - Ultrastar 2.1 GB Hard Drive, Технические характеристики

Страница: 27 / 232

3.4.3 Drive Ready Time
Ready The condition in which the drive is able to perform a media access command (eg. read, write)
immediately.
Power On This includes the time required for the internal self diagnostics.
3.4.4 Data Transfer Speed
Instantaneous disk-buffer transfer rate (Mbyte/sec) is derived by:
(Number of sectors on a track)*512*(revolution/sec)
Note: 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. This
gives a local average data transfer rate. It is derived by:
(Sustained Transfer Rate) = A/ ( B + C + D )
A = (Number of data sectors per cylinder) * 512
B = ((# of Surface per cylinder) - 1) * (Head switch time)
C = (Cylinder change time)
D = (# of Surface) * (One revolution time)
Instantaneous Buffer-Host Transfer Rate (Mbyte/sec) defines the maximum data transfer rate on SCSI
Bus. It also depends on the speed of the host.
The measurement method is given in 3.4.6, “Throughput” on page 15.
Figure 9. Drive Ready Time
Condition Typical Max.
Power On to Ready (DCAS-34330) 15 [ sec] 20 [ sec]
Power On to Ready (DCAS-32160) 12 [ sec] 18 [ sec]
Figure 10. Data Transfer Speed
Description Typical
Disk-Buffer Transfer (Zone 0)
(Instantaneous) 9.72 [ Mbyte/sec]
(Sustained) DCAS-34330 8.1 [ Mbyte/sec]
DCAS-32160 8.0 [ Mbyte/sec]
Disk-Buffer Transfer (Zone 7)
(Instantaneous) 6.08 [ Mbyte/sec]
(Sustained) DCAS-34330 5.1 [ Mbyte/sec]
DCAS-32160 5.0 [ Mbyte/sec]
Buffer-Host
50-pin FAST-20
68-pin / 80-pin FAST-20 Wide 20 [ Mbyte/sec]
40 [ Mbyte/sec]
Drive Characteristics
13