Maxtor 86480D8 Specifications download pdf (Page 12)

PRODUCT DESCRIPTION

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Logical Block Addressing

The Logical Block Address (LBA) mode can only be utilized in systems that support this form of translation. The cylinder,

head and sector geometry of the drive, as presented to the host, differs from the actual physical geometry.

The host AT computer may access a drive of set parameters: number of cylinders, heads and sectors per track, plus

cylinder, head and sector addresses. However, the drive can’t use these host parameters directly because of zoned recording

techniques. The drive translates the host parameters to a set of logical internal addresses for data access. The host drive

geometry parameters are mapped into an LBA based on this formula:

LBA = (HSCA - 1) + HHDA x HSPT + HNHD x HSPT x HCYA (1)

= (HSCA - 1) + HSPT x (HHDA + HNHD x HCYA) (2)

where HSCA = Host Sector Address, HHDA = Host Head Address, HCYA = Host Cylinder Address, HNHD = Host Number of Heads

HSPT = Host Sectors per Track

The LBA is checked for violating the drive capacity. If it does not, the LBA is converted to physical drive cylinder, head

and sector values. The physical address is then used to access the data stored on the disk and other drive related operations.

Defect Management Zone (DMZ)

Each drive model has a fixed number of spare sectors per drive, all of which are located at the end of the drive. Upon

detection of a bad sector that has been reassigned, the next sequential sector is used.

For example, if sector 3 is flagged, data that would have been stored there is “pushed down” and recorded in sector 4.

Sector 4 then effectively becomes sector 3, as sequential sectors are “pushed down” across the entire drive. The first spare

sector makes up for the loss of sector 3, and so maintains the sequential order of data. This push down method assures

maximum performance.

On-the-Fly Hardware Error Correction Code (ECC)

10 bits, single burst, guaranteed

Software ECC Correction

64 bits, single burst, guaranteed; 28 bits, double bursts, guaranteed

Automatic Park and Lock Operation

Immediately following power down, dynamic braking of the spinning disks delays momentarily allowing the read/write

heads to move to an inner mechanical stop. A small fixed magnet holds the rotary actuator in place as the disk spins down.

The rotary actuator is released only when power is again applied.

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Maxtor 86480D8 Specifications Page 12