Grass Valley PRS 250 RAID Storage System - Manual (Page 14)

Chapter 1 Introduction
1-4 RAID Instructions
Storage-control Processor (SP)
The SP consists of a printed circuit board with two or four memory modules (DIMMs)
and a bezel with status lights, and latches to secure the SP in place. The memory
modules provide 32 Mbytes of SP memory. The SP uses 4Mbytes of this memory for
system buffers. The remaining memory is available for system use.
Two status lights on the SP indicate the following:
Ready light (green) — Lights while the SP is powered on and operating normally.
Service light (amber) — Lights when the SP is not working properly.
The SPs are visible when you swing the fan module down from the back of the RAID
Storage chassis.
The SP processes data written to or read from the disk drive modules, and controls the
disk modules in the storage chassis through a synchronous SCSI bus. It has five
internal SCSI buses, each supporting four disk drive modules for a total of 20 disk
drive modules. The Disk Array Storage System Manager (dassmgr) uses an RS-232
connection to the RAID Storage chassis to communicate with an SP. Using the
dassmgr, you can set up RAID Storage memory, bind disk modules into logical units
(LUNs), update the RAID Storage Licensed Internal Code, and check RAID Storage
status.
A second SP increases the RAID chassis bandwidth for improved performance,
provided the two SPs are connected to separate SCSI busses. Do not connect both SPs
to the same SCSI bus.
IMPORTANT You should never attempt to replace any of the SP’s
components, except the memory modules.
Ready light
(green)
Service light
(amber)
Bezel
Printed-circuit
board Memory modules
Latch