8 Constellation.2 Serial ATA Product Manu al, Rev. B
3.5 Physical characteristics
Maximum height 14.8 mm (0.583 in)
Maximum width 70.0 mm (2.76 in)
Maximum length 100.5 mm (3.957 in)
Max weight
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)
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 0.7 0.85
Average 8.5 9.5
Full Stroke 16.96 17.96
Average latency: 4.16
*Measured in performance mode.
Note. These drives are designed to consistently meet the seek times represented in this manual. Ph ysical
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.
3.7 Start/stop times
Power-on to Ready (sec) 20 (max)
Standby to Ready (sec) 13 (max)
Ready to spindle stop (sec) 20 (max)