Formatted capacity, Default logical geometry

2.2Formatted capacity

Model	Formatted capacity*	Guaranteed sectors	Bytes per sector

ST95005620AS	500GB	976,773,168	512

ST93205620AS	320GB	625,142,448	512

ST92505610AS	250GB	488,397,168	512

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

2.2.1LBA mode

When addressing these drives in LBA mode, all blocks (sectors) are consecutively numbered from 0 to n–1,where n is the number of guaranteed sectors as defined above.

See Section 4.3.1, "Identify Device command" (words 60-61 and 100-103) for additional information about 48- bit addressing support of drives with capacities over 137GB.

2.2.2Solid State Hybrid feature

The Solid State Hybrid feature utilizes the addition of NAND Flash memory to enhance the performance of the drive. Short random accesses to the NAND Flash are faster than disc accesses due to the elimination of seek and rotational latencies and therefore it is used to store more frequently accessed data. The Momentus XT uses a proprietary algorithm which monitors drive activity and determines the optimum data to maintain in the NAND Flash for peak responsiveness. The Solid State Hybrid feature is self contained in the drive firmware and functions independent of the host hardware or operating system. There are no special host system requirements. Momentus XT can be installed in any standard SATA environment and will automatically opti- mize.

Specifics of the Solid State Hybrid Feature:

•Powerful ECC correction on data read from the NAND Flash.

•Maintains a list of defective NAND Flash blocks and maps them out of use.

•Additional bad blocks added during use will be added to the list of defective blocks and taken out of use.

•Storage functionality is preserved with no data loss with any wear out of the NAND Flash.

•No user intervention required.

2.3Default logical geometry

Cylinders	Read/write heads	Sectors per track

16,383	16	63

LBA mode