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10 Constellation SAS Product Manual, Rev. E
5.0 Performance characteristics
This section provides detailed information concerning performance-related characteristics and features of Con-
stellation drives.
5.1 Internal drive characteristics
ST9500430SS, ST9500431SS & ST9500432SS
Drive capacity 500 Gbytes (formatted, rounded off value)
Read/write data heads 6
Bytes per track 890,823 Bytes (average, rounded off values)
Bytes per surface 83,370 Mbytes (u
nformatted, rounded off value)
Tracks per surface (total) 123,148
Tracks (user accessible)
Tracks per inch 200,000 TPI (average)
Peak bits per inch 1,410,000 BPI
Areal density 283 Gbit/in
2
Internal data rate 75 - 142 Mbytes/sec (variable with zone)
Disc rotation speed 7,200 rpm
Avg rotational latency 4.16 msec
5.2 Seek performance characteristics
See Section 12.4.1, "SAS physical interface" on page 56 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.
,
(msec)
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.
8.2 8.6 8.0 8.4
Single track Typical
3,4
0.5 0.7 0.5 0.7
Full stroke Typical
3,4
17.55 18.02 17.35 17.82
2. Assumes no errors and no sector has been relocated.
Not including controller overhead
1, 2
(msec)
Read Write Read Write