IBM IC25N020ATDA04 - Travelstar 20 GB Hard Drive - Performance Characteristics; Command Overhead; Figure 11. Performance Characteristics

4.5 Performance characteristics
File performance is characterized by the following parameters:
! Command Overhead
! Mechanical Positioning
! Seek Time
! Latency
! Data Transfer Speed
! Buffering Operation (Look ahead/Write Cache)
Note: All the above parameters contribute to file performance. There are other parameters which contri-
bute to the performance of the actual system. This specification defines the essential file characteristics.
This specification does not include the system throughput as this is dependent upon the system and the
application.
The following table gives a typical value for each parameter. Detailed descriptions are found in
Section 5.0.
100100100100100Buffer-host data transfer (MB/s)
105 - 199125 - 235121 - 216125 - 235135 - 241Disk-buffer data transfer (Mb/s)
1.01.01.01.01.0Command overhead (ms)
3.03.03.03.05.0Power-on-to-ready (sec)
42004200420042005400Rotational Speed (RPM)
1414141414Average Random Seek Time For Write (ms)
1212121212Average Random Seek Time For Read (ms)
12 GB,
10 GB,
6 GB,
5 GB
Models
15 GB,
7.5 GB
Models
20 GB
Model
30 GB
Model
48 GB
Model
Function
Figure 11. Performance characteristics
4.5.1 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.
Travelstar 48GH, 30GN & 15GN hard disk drive specifications
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