(1) SCSI bus configuration
Up to eight SCSI devices operating as an initiator or a target can be connected to the SCSI bus for
the 8-bit SCSI and up to 16 SCSI devices operating as an initiator or a target can be connected to
the SCSI bus for the 16-bit SCSI in any combination.
For example, the system can be configured as multi-host system on which multiple host computers
that operate as initiator or connected through the SCSI bus.
Using disconnect/reconnect function, concurrent input/output processing is possible on multi-
SCSI devices.
(2) Addressing of peripheral device
Each SCSI device on the bus has its own unique address (SCSI ID:#n in Figure 1.1). For
input/output operation, a peripheral device attached to the SCSI bus that operates as target is
addressed in unit called as logical unit. A unique address (LUN: logical unit number) is assigned
for each logical unit.
The initiator selects one SCSI device by specifying that SCSI ID, then specifies the LUN to select
the peripheral device for input/output operation.
The HDD is constructed so that the whole volume of disk drive is a single logical unit, the
selectable number of SCSI ID and LUN are as follows:
• SCSI ID: 8-bit SCSI:Selectable from 0 to 7 (option for NP model, switch selectable)
16-bit SCSI:Selectable from 0 to 15 (switch selectable)
• LUN: 0 (fixed)
20 C141-E270
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