Seagate ST3400755SS Performance characteristics, Internal drive characteristics, Seek performance

4.0Performance characteristics

This section provides detailed information concerning performance-related characteristics and features of Cheetah NS SAS drives.

4.1Internal drive characteristics

	ST3400755SS	Gbytes (formatted, rounded off value)*
Drive capacity	400.0
Read/write data heads	8
Tracks per surface (total)	92,200	Tracks (user accessible)
Tracks per inch	155,000	TPI
Peak bits per inch	979k	BPI
Areal Density	151.7	Gbits/inch2
Internal data rate	725 to 1,211	Mbits/sec (variable with zone)
Disk rotation speed	10k	rpm
Avg rotational latency	2.98	msec

*One Gbyte equals one billion bytes when referring to hard drive capacity. Accessible capacity may vary depending on operating environment and formatting.

4.2Seek performance

See Section 9.4.1, "SAS physical interface" on page 51 and the SAS Interface Manual (part number 100293071) for additional timing details.

4.2.1Access time

Not Including controller overhead1, 2 (msec)

		Read	Write
Average	Typical	3.9	4.2
Single track	Typical	0.35	0.52
Full stroke	Typical	6.8	7.5

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 NS SAS Product Manual, Rev. B 11