Seagate ST336854FC manual Performance characteristics, Internal drive characteristics, Access time

4.0Performance characteristics

This section provides detailed information concerning performance-related characteristics and features of Cheetah 15K.4 FC drives.

4.1Internal drive characteristics

	ST3146954FC	ST373554FC	ST336854FC
Drive capacity	146.8	73.4	36.7	Gbytes (formatted, rounded off value)
Read/write data heads	8	4	2
Bytes per track	471,916	471,916	471,916	Bytes (average, rounded off values)
Bytes per surface	18,351	18,351	18,351	Mbytes (unformatted, rounded off value)
Tracks per surface (total)	50,864	50,864	50,864	Tracks (user accessible)
Tracks per inch	85,000	85,000	85,000	TPI
Peak bits per inch	628	628	628	KBPI
Internal data rate	685-1,142	685-1,142	685-1,142	Mbits/sec (variable with zone)
Disc rotation speed	15k	15k	15k	rpm
Avg rotational latency	2.0	2.0	2.0	msec

4.2Seek 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.

4.2.1Access time

Not including controller overhead1,2(msec)

		Read	Write
Average	Typical	3.5	4.0
Single track	Typical	0.27	0.45
Full stroke	Typical	7.4	7.9

1.Typical access times are measured under nominal conditions of temperature, voltage, and horizontal orientation as measured on a representative sample of drives.

2.Access to data = access time + latency time.

Cheetah 15K.4 FC Product Manual, Rev. B 11