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Constellation.2 SAS Product Manual, Rev. H 11
5.0 Performance characteristics
This section provides detailed information concerning performance-related characteristics and features of Con-
stellation.2 drives.
5.1 Internal drive characteristics
ST91000640SS ST9500620SS
ST91000641SS ST9500621SS
ST91000642SS ST9500622SS
Drive capacity 1000 500 Gbytes (formatted, rounded off value)
Read/write data heads 8 4
Bytes per track 732,998 732,998 Bytes (average, rounded off values)
Bytes per surface 125,069 125,069 MB (unformatted, rounded off value)
Tracks per surface (total) 165,800 165,800 Tracks (user accessible)
Tracks per inch 270,000 270,000 TPI (average)
Peak bits per inch 1,544,000 1,544,000 BPI
Areal density 417 417 Gb/in
2
Internal data rate 84 - 163 84 - 163 MB/s (variable with zone)
Disk rotation speed 7200 7200 rpm
Avg rotational latency 4.16 4.16 ms
5.2 Seek performance characteristics
See Section 12.4.1, "SAS physical interface" on page 63 and the SAS Interface Manual (part number
100293071) for additional timing details.
5.2.1 Access time
Including controller overhead
2
1
1. Execution time measured from receipt of the Command to the Response.
,
(ms)
Average Typical
43
3. Typical access times are measured under nominal conditions of temperature, voltage, and horizontal orientation as
measured on a representative sample of drives.
,
4. Access time = controller overhead + average seek time and applies to all data transfer commands.
Access to data = access time + latency time.
7.7 8.7 7.5 8.5
Single track Typical
3,4
0.23 0.44 0.23 0.44
Full stroke Typical
3,4
17.26 18.28 17.06 18.08
2. Assumes no errors and no sector has been relocated.
Not including controller overhead
1, 2
(ms)
Read Write Read Write