IBM DTCA-23240 - Travelstar 3.2 GB Hard Drive, Технические характеристики

Страница: 18 / 190

3.3 Performance Characteristics
File performance is characterized by the following parameters:
Command Overhead
Mechanical Positioning
−
Seek Time
−
Latency
Data Transfer Speed
Buffering Operation
Note: All the above parameters contribute to a file performance. There are other parameters which con-
tribute to the performance on the actual system. This specification tries to define the essential file character-
istics, not the system throughput which is dependent on the system and the application.
The following table gives a typical value of each parameter. The detail descriptions are followed in the next
sections.
Figure 5. Performance Parameter
3.3.1 Command Processing
Command overhead time is defined as the total time from when the command is received by the drive to the
start of motion of the actuator.
3.3.2 Average Seek Time (Including Settling)
Figure 6. Mechanical Positioning Performance
'Typical' and 'Max' are given throughout the performance specification by;
Typical Average of the drive population tested at nominal environmental
and voltage conditions.
Max Maximum value measured on any one drive over the full range of the environmental and
voltage conditions. (See section on Environment and D.C. Power Requirements.)
Function Typical
Average Random Seek Time For Read 13 msec
Average Random Seek Time For Write 14 msec
Rotational Speed 4000 rpm
Power On To Ready 2.8 sec
Command Overhead 1.0 msec
Disk-Buffer Data Transfer 83.4 - 51.7 Mbit/sec
Buffer-Host Data Transfer 16.6 MB/sec (PIO Mode-4)
33.3 MB/sec (Ultra D M A Mode-2)
Command Type Typical Max
Read 13 msec 16 msec
Write 14 msec 17 msec
10
O E M Specifications of DTCA-2xxxx 2.5 inch H D D