Advantech RAID-800S, Installation Reference Manual

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1 4 RAID-800S User's Manual
2.3.1 486DX Processor
The subsystem’s CPU is an Intel 486DX microprocessor. Its function is
to control all controller functions such as SCSI bus transfers, RAID
operation and configuration, data stripping, error recovery, and drive
rebuild.
2.3.2 Memory Subsystem and DRAM Cache
The subsystem can support up to a maximum of 128MB cache memory.
Its main function is to control the memory and addresses. Unless
otherwise requested, the subsystem is supplied with a 8MB DRAM. The
memory control unit provides a fast interface between the 486DX CPU
and the cache memory DRAM.
Important: Although the subsystem supports cache memory
expansion, we do not recommend users to perform this
on their own. This is because the subsystem requires
further testing after each memory expansion to ensure
reliability.
2.4 Controller Firmware
The subsystem’s firmware contains various programs executed by the
486DX microprocessor. This firmware, which resides in the onboard flash
EPROM, stores information even after power-off. It can be upgraded by
simply overwriting the previous information, thus there is no need for
any hardware replacement.
2.5 SCSI Bus Interface
The SCSI bus interface allows the controller to communicate with the
respective host system, as well as read or write data on several drives.
Each SCSI channel can connect up to 7 disk drives (15 drives for Ultra
Wide). The subsystem can work with all SCSI platforms.