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Micron Electronics, Inc.
Micron NetFRAME LV2000 Server System User’s Guide
Host Adapter SCSI ID—
Each device on the SCSI bus, including the adapter,
must have a unique ID. The ID defines the device, and the priority of the ID
determines which device controls the bus when two or more devices try to use
it at the same time. Each adapter on the bus, whether 8- or 16-bit, has a default
ID of 7, so the adapter always has the highest priority. This is the priority
model:
Device priority model
Highest priority ID
Lowest priority ID
8-bit devices (narrow SCSI) 7
0
16-bit devices (wide SCSI)
7 through 0
15 through 8
(In this case, ID 7 has the
highest priority and
ID 8 the lowest)
SCSI Parity Checking—
when enabled, the host adapter uses SCSI parity
checking to verify the accuracy of data transfer on the SCSI bus. If a device on
the bus does not support SCSI parity, the option must be disabled.
Host Adapter SCSI Termination—
the setting for this option is determined
by (1) the location of the host adapter on the bus and (2) whether the SCSI
devices connected to the bus are narrow, wide, or a combination. The bus
must have a set of resistors, called
terminators
, either installed in or enabled on
the first and last SCSI devices on the bus, or else data transfer may not be
accurate. The host adapter itself is the SCSI device at one end of the bus, and
termination on the adapter cannot be disabled. On a 16-bit adapter, termination
is enabled for both the low byte (bits 0-7) and the high byte (bits 8-15). If there
is no 8-bit adapter at the end of the bus, you must disable termination by using
the option in the SCSI
Select
Configuration menu. This is the termination model:
Host adapter location
SCSI devices
Host Adapter SCSI
connected to bus
Termination choice
Installed at end of bus
only
8-bit,
or
only
16-bit
Installed at end of bus
both
8-bit and 16-bit
Not at end of bus*
only
16-bit
Not at end of bus*
both
8-bit and 16-bit
*In this system, the host adapter on the system board is always at one end of the bus.
Low ON/High ON (default)
Low ON/High ON (same as
default)
Note:
Last device must be
16-bit and terminated.
Low OFF/High OFF
Low OFF/High On
