Technical information

HGST Ultrastar C15K600 Hard Disk Drive Specification
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4.4
Performance Characteristics
Drive performance is characterized by the following parameters:
 Command overhead
 Mechanical head positioning
- Seek time
- Latency
 Data transfer speed
 Buffering operation (read ahead/write cache)
Note: All the above parameters contribute to drive performance. There are other parameters that contribute to the
performance of the actual system. This specification tries to define the bare drive characteristics, not system
throughput, which depends on the system and the application.
4.4.1
Mechanical Positioning
4.4.1.1
Average Seek Time (including settling)
Table 6 Mechanical Positioning Performance
Model
Command
Typical, ms
Max, ms
600/450/300 GB
4K/512
Read 2.9 3.3
Write 3.1 3.8
The terms “Typical” and “Max” are used throughout this specification with the following meanings:
Typical The average of the drive population tested at nominal environmental and voltage conditions.
Max The maximum value measured on any one drive over the full range of the environmental and voltage
conditions. (See section 8 “Environment” and section 9 “DC Power Requirements”)
The seek time is measured from the start of the actuator’s motion to the start of a reliable read or write operation.
“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.
Weighted average =
max 1 n–+ ) Tnin Tnout+(⋅()=
n1=
Max
∑
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