Hitachi HTS421210H9AT00, Specifications

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Travelstar 4K120 Hard Disk Drive Specification
18
“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 25 and Section 6.2, “DC power require-
ments” on page 27 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
(Max+1-n)(Tn
in
+ Tn
out
)
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.
4.4.2.3 Single track seek time (without command overhead, including settling)
Single track seek is measured as the average of one (1) single track seek from every track in both directions
(inward and outward).
Table 10: Full stroke seek time
Command type Typical (ms) Max (ms)
Read 20.0 25.0
Write 21.0 26.0
Table 11: Single track seek time
Command type Typical (ms) Max (ms)
Read 1.0 2.0
Write 1.1 2.2