Mechanical Positioning; Table 6. Mechanical Positioning Performance; Table 7. Full Stroke Seek Time - Hitachi 7K400 - Deskstar Hard Drive Specifications

4.5.2 Mechanical positioning

4.5.2.1 Average seek time (including settling)
Table 6: Mechanical positioning performance
Command type
Read
Write
Read (Quiet Seek mode)
Write (Quiet Seek mode)
The terms "Typical" and "Max" are used throughout this document and are defined as follows:
Typical The 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.
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 mea-
sured as the weighted average of all possible seek combinations.
Weighted Average = ––––––––––––––––––––––––––––
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
4.5.2.2 Full stroke seek time (without command overhead, including settling)
Table 7: Full stroke seek time
Function
Read
Write
Read (Quiet Seek mode)
Write (Quiet Seek mode)
Full stroke seek is measured as the average of 1,000 full stroke seeks with a random head switch from both directions (inward
and outward).
Typical (ms) Max (ms)
8.2 9.2
9.2 10.2
19.5 20.5
20.5 21.5
max
Σ (m10 n)(Tnin + Tnout)
n=1
(max + 1)(max)
Typical (ms)
14.7
15.7
32.5
33.5
Deskstar 7K400 Hard Disk Drive specification
Max (ms)
17.7
18.7
35.5
36.5
15