Western Digital WDE2170 - Manual (Page 32)

Advanced Product Features WD Enterprise WDE2170/WDE4360
RELEASED 04-08-97 4079-001045 Rev. B 24
3.16. Option Block Functions
The firmware uses several pins on the option block to modify the drive characteristics.
The definitions for the jumpers follow:
SCSI ID: Four jumpers are used to identify the default SCSI ID for the drive.
Disable Auto Start: Use of this jumper disables Auto Start, meaning the drive does
not spin-up until a START UNIT command is issued. Without this jumper, the
drive will spin-up and prepare itself at power on without having to receive a
START UNIT command.
Auto Start Delay: Use of this jumper allows the Auto Start to incorporate a delay.
The delay time equals the SCSI ID multiplied by 4 seconds.
Disable Target Initiated Synchronous/Wide Negotiation: Use of this jumper
dictates that the drive cannot initiate either synchronous negotiation or wide
negotiation. Without this jumper the drive will initiate synchronous and wide
negotiation when appropriate.
Disable Unit Attention: This controls whether a CHECK CONDITION status is
reported following a Power On or Reset sequence. A REQUEST SENSE command
following one of those conditions still yields the correct sense data for the UNIT
ATTENTION condition, as sense data is generated regardless of the jumper setting.
A jumper on this pin disables the generation of a CHECK CONDITION for the
Power On and Reset UNIT ATTENTION conditions. With no jumper attached, a
CHECK CONDITION status is reported in these situations.
SCSI Configure Automagically (SCAM): The drive is SCAM levels 1 and 2
compliant, which eases user configuration of SCSI IDs and allows for hot plugging
on single and multiple drive systems. Use of this jumper allows the drive to function
as a SCAM level 2 device. Without the jumper the drive is not a SCAM device.
Active SCSI Termination: To ensure reliable communication, the SCSI bus must
be properly terminated. Use of this jumper enables active termination on the drive.
Without this jumper, active termination is disabled.
Note: For more information on the option block, refer to section 5.