Cheetah 15K.5 FC Product Manual, Rev. F
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4.0 Performance characteristics
This section provides detailed information concerning performance-related characteristics and features of
Cheetah 15K.5 FC drives.

4.1 Internal drive characteristics

ST3300655FC ST3146855FC ST373455FC
Drive capacity* 300.0 146.8 73.4 Gbytes (formatted, rounded off value)
Read/write data heads 8 4 2
Bytes per track 74,340 74,340 74,340 Bytes (average, rounded off values)
Tracks per inch 125,000 125,000 125,000 TPI
Peak bits per inch 890k 890k 890k BPI
Areal density 110 110 110 Gbits/inch2
Internal data rate 960 to 1607 960 to 1607 960 to 1607 Mbits/sec (variable with zone)
Disc rotation speed 15k 15k 15k rpm
Avg rotational latency 2.0 2.0 2.0 msec
*One Gbyte equals one billion bytes when referring to hard drive capa city. Accessible capacity may vary depending on operating environment
and formatting.

4.2 Seek performance characteristics

See Section 9.5, "FC-AL physical interface" on page 64 and the Fibre Channel Interface Manual (part number
77767496) for additional timing details.
4.2.1 Access time
Not including controller overhead1,2(msec)
1. Typical access times are m easured under nominal conditions of temperature, voltage,
and horizontal orientation as measured on a representative sample of drives.
2. Access t o data = access time + latency time.
Read Write
Average Typica l 3.5 4.0
Single track Typical 0.2 0.4
Full stroke Typ ical 6.8 7.5