Glossary
GL-2 C141-E203-01EN
MTTR
Mean time to repair. The MTTR is the average time required for a service person
to diagnose and repair a faulty drive.
PIO (Programmed input-output)
Mode to transfer data under control of the host CPU
Positioning
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.
Status
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.
VCM
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.