Reset; Reset Sources; Reset Actions - IBM Ultrastar 36LZX Specifications

11.16 Reset

The Reset condition is used to clear all SCSI devices from the bus. This condition takes precedence over
all other phases and conditions. After a reset condition is detected and the reset actions completed, the
target returns to a 'SCSI bus enabled' state that allows the target to accept SCSI commands.
This device uses the Hard reset option as defined in the SCSI-3 standard.

11.16.1 Reset Sources

There are four sources of resets detected by the target:
Reset Name
Power-On Reset
Self-Initiated reset
SCSI Bus Reset
SCSI Bus Device
Reset Message

11.16.2 Reset Actions

The action taken by the drive following a reset is dependent on the source of the reset.
11.16.2 .1 Power-On reset and Self-Initiated reset
These two reset conditions cause the following to be performed in the order shown:
1. A power-up sequence
2. A startup sequence is necessary to put the drive in a ready state
11.16.2 .2 SCSI Bus reset and SCSI Bus Device Reset message
These two reset conditions cause the following to be performed.
- If reset goes active while the power-up sequence is in progress, the power-up sequence is started
over.
- If the Auto Start pin is grounded and a startup sequence has not yet completed, a startup sequence
will be re-attempted from the beginning.
Note: The power-up sequence, having already completed, is not rerun.
- If reset occurs while a physical sector is being written, the write operation is disabled after the
current physical sector is written. Data is not lost as long as power stays valid until the physical
sector being written is completed.
Reset Source
This is the signal generated by the hardware at initial power-on
This is a software-generated reset that occurs when a catastrophic error is
detected by the microcode.
This is a reset generated when the SCSI bus control line RST goes active.
This is the reset generated by the SCSI Bus Device Reset Message(0Ch).
Ultrastar 36LZX hard disk drive specifications
229