Advantech RAID-800S, Installation Reference Manual

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Chapter 2 Functions 1 5
2.6 User to RAID-800S Interface
The user can communicate with the subsystem via (1) the key controls
and LCD screen located at the RAID disk array controller unit’s front
panel or (2) using a terminal or PC connected to the subsystem via the
serial monitor port.
2.7 SCSI Functions
The controller provides two Ultra Wide SCSI bus interfaces (40MB/s,
using 68-pin connector) to connect to the host system.
Besides, the controller unit also provides two SCSI disk device channels
as shown on page 6.
Each host channel must be assigned a unique SCSI ID ranging from 0 -
15. The default value is ID 0. You can specify a different SCSI ID for
each host channel.
2.8 Disk Drive Organization
The subsystem arranges the SCSI drives connected to it as a physical
drive group and logical unit (LUN).
2.8.1 Physical Drive Groups
The subsystem has up to a maximum of seven individual disk drives
which can be used to form a physical drive group. This drive group will
comprise the array’s logical unit capacity. Take note - if the capacity of
the three hard drives in a drive group are not identical, the capacity of
the drive group will be the multiple of the smallest capacity hard drive.
To calculate the total size of a particular drive group, multiply the size of
the smallest disk in the drive group by the number of disk in the group.
2.8.2 Logical Unit Number (LUNs)
A logical unit or the system drive is a drive group or a combination of
up to four drive groups read by the host system as a single logical
device. Each logical unit is given a unique logical number (LUN). A LUN
number system begins at 0, 1, 2, 3, and so on. The subsystem supports