IBM IC25N020ATDA04 Hard Drive Specifications - Page 31

Mechanical positioning, 5.2.1 Average seek time including settling, 5.2.2 Full stroke seek

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4.5.2 Mechanical positioning 4.5.2.1 Average seek time (including settling) Command Type Read Write Typical (ms) 12 14 Max (ms) 16 17 Figure 12. Mechanical positioning performance Typical and Max are defined throughout the performance specification 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 requirements" on page 27.) The seek time is measured from the start of motion of the actuator to the start of a reliable read or write operation. A reliable read or write operation implies that error correction/recovery is not employed to correct arrival problems. The Average Seek Time is measured as the weighted average of all possible seek combinations. max. Σ (max. + 1 - n)(Tnin + Tnout) n=1 Weighted Average max. + 1)(Tnin + Tnout) 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 Command Type Read Write Typical (ms) 23.0 24.0 Max. (ms) 30.0 31.0 Figure 13. Full stroke seek time Full stroke seek time in milliseconds is the average time of 1000 full stroke seeks. Travelstar 48GH, 30GN & 15GN hard disk drive specifications 17

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4.5.2 Mechanical positioning
4.5.2.1 Average seek time (including settling)
17
14
Write
16
12
Read
Max (ms)
Typical (ms)
Command Type
Figure 12. Mechanical positioning performance
Typical and Max are defined throughout the performance specification as follows:
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
requirements" on page 27.)
Max
Average of the drive population tested at nominal environmental and voltage conditions.
Typical
The seek time is measured from the start of motion of the actuator to the start of a reliable read or write
operation. A reliable read or write operation implies that error correction/recovery is not employed to cor-
rect 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)(Tn
in
+ Tn
out
)
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
4.5.2.2 Full stroke seek
31.0
24.0
Write
30.0
23.0
Read
Max. (ms)
Typical (ms)
Command
Type
Figure 13. Full stroke seek time
Full stroke seek time in milliseconds is the average time of 1000 full stroke seeks.
Travelstar 48GH, 30GN & 15GN hard disk drive specifications
17