Hitachi Deskstar 7K250, Технические характеристики

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Deskstar 7K250 Hard Disk Drive Specification
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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. (See Section 6.2, “Environment” on page 27 and Section 6.3, “DC power require-
ments” on page 29 for ranges.)
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 measured as the weighted average of all possible seek combinations.
max
Σ
(m10 n)(Tnin + Tnout)
n=1
Weighted Average = ––––––––––––––––––––––––––––
(max + 1)(max)
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
4.4.2.2 Full stroke seek time (without command overhead, including settling)
Full stroke seek is measured as the average of 1,000 full stroke seeks with a random head switch from both direc-
tions (inward and outward).
4.4.2.3 Head switch time (head skew)
Head switch time is defined as the amount of time required by the fixed disk to complete a seek of the next sequen-
tial track after reading the last sector in the current track
The measuring method is given in 4.4.5, “Throughput” on page 19.
Table 6: Full stroke seek time
Function Typical (ms) Max (ms)
Read
120-250GB 14.7 17.7
40-80GB 15.1 18.1
Write
120-250GB 15.7 18.7
40-80GB 16.1 19.1
Read (Quiet Seek mode) 32.5 35.5
Write (Quiet Seek mode) 33.5 36.5
Table 7: Head switch time
Head switch time-typical (ms)
87/90/93.5 KTPI 1.4