Seagate ST91000642SS Constellation.2 SATA Product Manual - Page 14

Recording and interface technology, Physical characteristics, Seek time

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3.4 Recording and interface technology Interface Recording method Recording density, KBPI (Kb/in max) Track density, KTPI (Ktracks/in avg) Areal density (Gb/in2 avg) Spindle speed (RPM) (± 0.2%) Internal data transfer rate (Mb/s max) Sustained data transfer rate (MB/s max) I/O data-transfer rate (MB/s max) All models Serial ATA (SATA) Perpendicular 1544 270 417 7200 1304 115 600 3.5 Physical characteristics Weight: (maximum) 1TB models 500GB models 250GB models Cache buffer 200 g (0.441 lb) 183 g (0.403 lb) 179 g (0.395 lb) 64 Mbytes (65,536 KB) Note. Refer to Figure 6, page 26 for detailed mounting configuration dimensions. 3.6 Seek time Seek measurements are taken with nominal power at 25°C ambient temperature. All times are measured using drive diagnostics. The specifications in the table below are defined as follows: • Track-to-track seek time is an average of all possible single-track seeks in both directions. • Average seek time is a true statistical random average of at least 5,000 measurements of seeks between random tracks, less overhead. *Typical seek times (ms) Track-to-track Average Full Stroke Average latency: Read 0.23 7.5 17.06 4.16 Write 0.44 8.5 18.08 *Measured in performance mode. Note. These drives are designed to consistently meet the seek times represented in this manual. Physical seeks, regardless of mode (such as track-to-track and average), are expected to meet the noted values. However, due to the manner in which these drives are formatted, benchmark tests that include command overhead or measure logical seeks may produce results that vary from these specifications. 8 Constellation.2 Serial ATA Product Manual, Rev. F

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8
Constellation.2 Serial ATA Product Manual, Rev. F
3.4
Recording and interface technology
All models
Interface
Serial ATA (SATA)
Recording method
Perpendicular
Recording density, KBPI (Kb/in max)
1544
Track density, KTPI (Ktracks/in avg)
270
Areal density (Gb/in
2
avg)
417
Spindle speed (RPM) (± 0.2%)
7200
Internal data transfer rate (Mb/s max)
1304
Sustained data transfer rate (MB/s max)
115
I/O data-transfer rate (MB/s max)
600
3.5
Physical characteristics
Weight: (
maximum)
1TB models
500GB models
250GB models
200 g (0.441 lb)
183 g (0.403 lb)
179 g (0.395 lb)
Cache buffer
64 Mbytes (65,536 KB)
Note.
Refer to Figure 6, page 26 for detailed mounting configuration dimensions.
3.6
Seek time
Seek measurements are taken with nominal power at 25°C ambient temperature. All times are measured using
drive diagnostics. The specifications in the table below are defined as follows:
•
Track-to-track seek time is an average of all possible single-track seeks in both directions.
•
Average seek time is a true statistical random average of at least 5,000 measurements of seeks between
random tracks, less overhead.
*Typical seek times (ms)
Read
Write
Track-to-track
0.23
0.44
Average
7.5
8.5
Full Stroke
17.06
18.08
Average latency:
4.16
*Measured in performance mode.
Note.
These drives are designed to consistently meet the seek times represented in this manual. Physical
seeks, regardless of mode (such as track-to-track and average), are expected to meet the noted
values. However, due to the manner in which these drives are formatted, benchmark tests that
include command overhead or measure logical seeks may produce results that vary from these
specifications.