MHW2080AT, MHW2060AT, MHW2040AT DISK DRIVES

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MHW2080AT, MHW2060AT, MHW2040AT DISK DRIVES | Manualzz

Glossary

Actuator

Head positioning assembly. The actuator consists of a voice coil motor and head arm. If positions the read-write (R-W) head.

AT bus

A bus between the host CPU and adapter board

ATA (AT Attachment) standard

The ATA standard is for a PC AT interface regulated to establish compatibility between products manufactured by different vendors. Interfaces based on this standard are called ATA interfaces.

BIOS standard for drives

The BIOS standard collectively refers to the parameters defined by the host, which, for example, include the number of cylinders, the number of heads, and the number of sectors per track in the drive. The physical specifications of the drive do not always correspond to these parameters.

The BIOS of a PC AT cannot make full use of the physical specifications of these drivers. To make the best use of these drives, a BIOS that can handle the standard parameters of these drives is required.

Command

Commands are instructions to input data to and output data from a drive.

Commands are written in command registers.

Data block

A data block is the unit used to transfer data. A data block normally indicates a single sector.

DE

Disk enclosure. The DE includes the disks, built-in spindle motor, actuator, heads, and air filter. The DE is sealed to protect these components from dust.

Master (Device 0)

The master is the first drive that can operate on the AT bus. The master is daisychained with the second drive which can operate in conformity with the ATA standard.

C141-E250 GL-1

Glossary

MTBF

Mean time between failures. The MTBF is calculated by dividing the total operation time (total power-on time) by the number of failures in the disk drive during operation.

MTTR

PIO (Programmed input-output)

Mode to transfer data under control of the host CPU

Positioning

Mean time to repair. The MTTR is the average time required for a service person to diagnose and repair a faulty drive.

Sum of the seek time and mean rotational delay

Power save mode

The power save modes are idle mode, standby mode, and sleep mode.

In idle mode, the drive is neither reading, writing, nor seeking data. In standby mode, the spindle motor is stopped and circuits other than the interface control circuit are sleeping. The drive enters sleep mode when the host issues the SLEEP command.

Reserved

Reserved bits, bytes, and fields are set to zero and unusable because they are reserved for future standards.

Rotational delay

Time delay due to disk rotation. The mean delay is the time required for half a disk rotation. The mean delay is the average time required for a head to reach a sector after the head is positioned on a track.

Seek time

The seek time is the time required for a head to move from the current track to another track. The seek time does not include the mean rotational delay.

Slave (Device 1)

The slave is a second drive that can operate on the AT bus. The slave is daisychained with the first drive operating in conformity with the ATA standard.

GL-2 C141-E250

Status

VCM

Glossary

The status is a piece of one-byte information posted from the drive to the host when command execution is ended. The status indicates the command termination state.

Voice coil motor. The voice coil motor is excited by one or more magnets. In this drive, the VCM is used to position the heads accurately and quickly.

C141-E250 GL-3

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