Hitachi HUS154530VLF400 User Manual
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.)
(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.
measured as the weighted average of all possible seek combinations.
Weighted average =
Where:
max
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
(
)
⋅
------------------------------------------------------------------------------------------------