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CHEETAH 15K.7 SAS PRODUCT MANUAL, REV. F 8
4.0 PERFORMANCE CHARACTERISTICS
This section provides detailed information concerning performance-related characteristics and features of Cheetah 15K.7
drives.
4.1 INTERNAL 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/inch
2
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.
4.2 SEEK TIME
See Section 11.4.1, "SAS physical interface" on page 47 and the SAS Interface Manual (part number 100293071) for
additional timing details.
4.2.1 Access time
NOT INCLUDING CONTROLLER OVERHEAD
2
(MSEC)
1
1. Typical access times are measured under nominal conditions of temperature, voltage, and horizontal
orientation as measured on a representative sample of drives.
,
Average Typical 3.4 3.9
Single track Typical 0.2 0.44
Full stroke Typical 6.6 7.4
4.2.2 Format command execution time (minutes)
When changing sector sizes, the format times shown below may need to be increased by 30 minutes.
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).
2. Access to data = access time + latency time.
READ WRITE
600GB 450GB 300GB
Maximum (with verify) 119 90 58
Maximum (without verify) 60 45 29