IBM DARA-206000 - Travelstar 12 GB Hard Drive, Specifications

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3.3.1 Command Processing
Command overhead time is defined as the total time from when the command is received by the drive to the
start of motion of the actuator.
3.3.2 Average Seek Time (Including Settling)
Figure 6. Mechanical Positioning Performance
'Typical' and 'Max' are given throughout the performance specification by;
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 on Environment and D.C. Power Requirements.)
The seek time is measured from the start of motion of the actuator to the start of a reliable read or write
operation. Reliable read or write implies that error correction/recovery is not employed to correct for arrival
problems. The Average Seek Time is measured as the weighted average of all possible seek combinations.
Weighted Average =
∑
max
n = 1
( max + 1
−
n) (Tn.in + Tn.out)
( max + 1) ( max)
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
3.3.3 Single Track Seek Time
Figure 7. Single Track Seek Time
The single track seek time includes settling time but does not include command overhead.
Single track seek is measured as the average of one (1) single track seek from every track in both directions
(inward and outward).
Command Type Typical Max
Read 12 msec 16 msec
Write 14 msec (except DARA-225000)
13 msec (DARA-225000)
17 msec
Function Typical Max
Read 2.5 msec 4.0 msec
Write 3.0 msec 4.5 msec
Drive Characteristics
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