Hitachi ULTRASTAR 15K450 HUS154530VLF400 - Manual (Page 27)

Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
11
4.5.1 Mechanical positioning
4.5.1.1 Average seek time (including settling)
Table 7: Mechanical positioning performance
“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 8.0, “Environment” on page 25 and Section 9.0, “DC Power Requirements” on page 29 for
ranges.)
Seek time is measured from the start of the actuator’s motion to the start of a read or write operation. Average seek time is
measured as the weighted average of all possible seek combinations.
Weighted average =
Where:
max
= Maximum seek length
n = Seek length (1 to max)
Tn.in = Inward measured seek time for an n track seek
Tn.out = Outward measured seek time for an n track seek
Model Command Typical (ms) Max
450 GB Read 3.3 5.0
Write 3.8 5.4
300 GB Read 3.1 4.5
Write 3.6 5.1
max 1 n – +
) Tnin Tnout
+
( ⋅ ( )
=
n 1 =
Max
∑
max 1 +
( ) max ( ) ⋅
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