Hitachi 7K100 Hard Drive Specifications - Page 28

Mechanical positioning

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4.4.2 Mechanical positioning 4.4.2.1 Average seek time (including settling) Table 5: Mechanical positioning performance Command type Typical (ms) Max (ms) Read 10 16 Write 11 17 "Typical" and "Max" are used throughout this document and are defined as follows: 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 6.1, "Environment" on page 21 and Section 6.2, "DC power require- ments" on page 24 for ranges.) The seek time is measured from the start of the actuator's motion to the start of a reliable read or write operation. A reliable read or write implies that error correction or recovery is not used to correct arrival problems. The average seek time is measured as the weighted average of all possible seek combinations. max Σ (m + 1 - n)(Tn + Tn) n=1 Weighted Average (max + 1)(max) where max n Tnin Tnout = maximum seek length = seek length (1 to max) = inward measured seek time for an n track seek = outward measured seek time for an n track seek 4.4.2.2 Full stroke seek time Table 6: Full stroke seek time Command type Typical (ms) Max (ms) Read 18 30 Write 19 31 Full stroke seek is measured as the average of 1,000 full stroke seeks. Travelstar 7K100 Hard Disk Drive Specification 14

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Travelstar 7K100 Hard Disk Drive Specification
14
4.4.2
Mechanical positioning
4.4.2.1
Average seek time (including settling)
“Typical” and “Max” are used throughout this document and are defined as follows:
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 6.1, “Environment” on page 21 and Section 6.2, “DC power require-
ments” on page 24 for ranges.)
The seek time is measured from the start of the actuator’s motion to the start of a reliable read or write operation. A
reliable read or write implies that error correction or recovery is not used to correct arrival problems. The average
seek time is measured as the weighted average of all possible seek combinations.
max
Σ
(m + 1 - n)(Tn + Tn)
n=1
Weighted Average =
––––––––––––––––––––––––––––
(max + 1)(max)
where
max
= maximum seek length
n
= seek length (1 to max)
Tnin
= inward measured seek time for an n track seek
Tnout
= outward measured seek time for an n track seek
4.4.2.2
Full stroke seek time
Full stroke seek is measured as the average of 1,000 full stroke seeks.
Table 5: Mechanical positioning performance
Command type
Typical (ms)
Max (ms)
Read
10
16
Write
11
17
Table 6: Full stroke seek time
Command type
Typical (ms)
Max (ms)
Read
18
30
Write
19
31