IBM DTTA-351010 - Deskstar 10.1 GB Hard Drive, Specifications

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3.3 Performance Characteristics
A 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 that contribute
to the performance of the actual system. This specification tries to define the bare file characteristics, not the
system throughput which will depends on the system and the application.
3.3.1 Command Overhead
Command overhead is defined as the time required:
from the command is written into the command register by a host
to the assertion of D R Q for the first data byte of a R E A D command when the requested data is not in
the buffer
exclude
−
Physical seek time
−
Latency time
Figure 3. Command Overhead
Note: The above table gives an average time.
3.3.2 Mechanical Positioning
3.3.2.1 Average Seek Time (Without Command Overhead, Including Settling)
Figure 4. 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.
Command Type (File is in quiescence state) Time(Typical) Time(Typical)
for Queued
command
Read(Cache not hit) (from Command Write to Seek Start) 0.60 msec 0.60 msec
Read(Cache hit) (from Command Write to D R Q ) 0.10 msec 0.10 msec
Write (from Command Write to D R Q ) 0.015 msec 0.01 msec
Seek (from Command Write to Seek Start) 0.50 msec Not applicable
Command Type Typical Max
Read 8.5 msec 9.5 msec
Write 9.5 msec 10.5 msec
Drive Characteristics
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