IBM DTLA-305040 - Deskstar 41.1 GB Hard Drive, Технические характеристики

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4.4.1 Command overhead
Command overhead is defined as the time required
Ÿ
from the time the command is written into the command register by a host
Ÿ
to the assertion of DRQ for the first data byte of a READ command when the requested data is not in
the buffer
Ÿ
excluding
- Physical seek time
- Latency
The table below gives average command overhead.
not applicable 0.3 Seek (from Command Write to Seek Start)
0.05 0.015 Write (from Command Write to DRQ)
0.1 0.1 Read (Cache hit) (from Command Write to DRQ)
0.3 0.3 Read (Cache not hit) (from Command Write to Seek Start)
Time (Typical) for
queued command
(ms)
Time (Typical)
(ms)
Command type (Drive is in quiescent state)
Figure 4. Command overhead
4.4.2 Mechanical positioning
4.4.2.1 Average seek time (without command overhead, including settling)
10.2 11.2 9.2 10.2 Write
9.2 10.2 8.2 9.2 Read
DTLA-307XXX DTLA-305XXX DTLA-307XXX DTLA-305XXX
Max (ms) Typical (ms) Command
Type
Figure 5. Mechanical positioning performance
The terms “Typical” and “Max” are used throughout this specification with the following meanings:
Typical. The average of the drive population tested at nominal environmental and voltage con-
ditions.
Max. The maximum value measured on any one drive over the full range of the environmental
and voltage conditions. (See 7.4 “Environment” on page 0 and 7.5 “DC Power Requirements” on
page 0.
Deskstar 40GV & 75GXP hard disk drive specifications
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