Seagate ST3300457SS manual Performance Characteristics, Internal Drive Characteristics, Seek Time

4.0PERFORMANCE CHARACTERISTICS

This section provides detailed information concerning performance-related characteristics and features of Cheetah 15K.7 drives.

4.1INTERNAL DRIVE CHARACTERISTICS

	ST3600057SS	ST3450857SS	ST3300657SS
	ST3600957SS	ST3450757SS	ST3300557SS
	ST3600857SS	ST3450657SS	ST3300457SS
Drive capacity	600	450	300	Gbytes (formatted, rounded off value)*
Read/write data heads	8	6	4
Tracks per inch	165,000	165,000	165,000	TPI
Peak bits per inch	1,361	1,361	1,361	KBPI
Areal Density	225	225	225	Gbits/inch2
Internal data rate	1.49 - 2.37	1.49 - 2.37	1.49 - 2.37	Gbits/sec (max)
Disk 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 capacity. Accessible capacity may vary depending on operating environment and formatting.

4.2SEEK TIME

See Section 11.4.1, "SAS physical interface" on page 47 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	3.4	3.9
Single track	Typical	0.2	0.44
Full stroke	Typical	6.6	7.4

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.

4.2.2Format command execution time (minutes)

When changing sector sizes, the format times shown below may need to be increased by 30 minutes.

	600GB	450GB	300GB
Maximum (with verify)	119	90	58
Maximum (without verify)	60	45	29

Note. There is approximately a 1.5 increase in time to format a SED drive versus a non-SED drive of the same capacity.

Execution time measured from receipt of the last byte of the Command Descriptor Block (CDB) to the request for a Status Byte Transfer to the Initiator (excluding connect/disconnect).

CHEETAH 15K.7 SAS PRODUCT MANUAL, REV. F 8