Performance Characteristics; Command Overhead; Table 4. Performance Characteristics - Hitachi 7K100 - Travelstar - Hard Drive Specifications

4.4 Performance characteristics

Drive performance is characterized by the following parameters:

• Command overhead

• Mechanical head positioning
- Seek time
- Latency
• Data transfer speed
• Buffering operation (read ahead/write cache)
Note: All the above parameters contribute to drive performance. There are other parameters that contribute to the
performance of the actual system. This specification defines the essential characteristics of the drive. It does not
include system throughput which is dependent on the system and the application.
The following table gives a typical value for each parameter. The detailed descriptions are found in Section 5.0,
"Data integrity" beginning on page 17.
Table 4: Performance characteristics
Function
Average random seek time - read (ms)
Average random seek time - write (ms)
Rotational speed (RPM)
Power-on-to-ready (sec)
Command overhead (ms)
Disk-buffer data transfer (Mb/s)
Buffer-host data transfer (MB/s)
4.4.1 Command overhead
Command overhead time is defined as the interval from the time that a drive receives a command to the time that
the actuator starts its motion
10
11
7200
4.0
1.0
267 - 629
100
Travelstar 7K100 Hard Disk Drive Specification
13