Maxtor manual Maxtor Atlas 10K V G-7

GLOSSARY

MICROSECOND (µs) – One millionth of a second (.000001 sec.).

MILLISECOND (ms) – One thousandth of a second (.001 sec.).

MTBF – Mean Time Between Failure. Reliability rating indicating the failure rate expected of a product expressed in power on hours (POH). Since manufacturers differ in the ways they determine the MTBF, comparisons of products should always take into account the MTBF calculation method.

MTTR – Mean Time To Repair. The average time it takes to repair a drive that has failed for some reason. This only takes into consideration the changing of the major sub-assemblies such as circuit board or sealed housing. Component level repair is not included in this number as this type of repair is not performed in the field.

N

.NANOSECOND (ns) – One billionth of a second (0.000 000 001 second or 10-9 second).

NEXUS – A relationship between two devices that begins with the establishment of an initial connection and ends with the completion of an I/O process. A nexus relationship is further defined by the letters I (initiator), T (target), L (logical unit), R (target routine), x (either L or R), Q (queue tag), and x_y (either an x or a Q)

O

OVERHEAD – Command overhead refers to the processing time required by the controller, host adapter, or drive prior to the execution of a command. Lower command overhead yields higher drive performance. Disk overhead refers to the space required for non-data information such as location and timing. Disk overhead often accounts for about ten percent of drive capacity. Lower disk overhead yields greater disk capacity.

OVERWRITE – To write data on top of existing data, erasing it.

OXIDE – A metal-oxygen compound. Most magnetic coatings are combinations of iron or other metal oxides, and the term has become a general one for the magnetic coating on tape or disk.

P

PARITY – An error checking technique wherein the sum of the bits in a data byte is used to set or reset an extra parity bit, depending on whether the sum is an odd or an even number. A second parity check after the data is transferred to a new location checks that the new parity bit matches the transferred bit. Parity checking can only detect an odd number of bit errors (1,3,5, etc.). Parity is defined as odd or even, depending on which condition (odd or even) is used to set the parity bit.

PARKING ZONE – A position in a non-data area on a disk platter reserved for resting the heads when power is off. Using this area prevents the heads from touching the surface in data areas upon power down, adding to the data integrity and reliability of the disk drive. The parking zone is most often inside the disk's inner-most cylinder.

PARTITION – A portion of a hard disk dedicated to a particular operating system and application and accessed as a single logical volume.

PERFORMANCE – A measure of the speed of the drive during normal operation. Factors affecting performance are seek times, transfer rate and command overhead.

Maxtor Atlas 10K V G-7