Components

CPU

The MegaRAID controller uses the 64-bit Intel i960RN Intelligent I/O processor with an

 

embedded 32-bit 80960 Jx RISC processor that runs at 100 MHz. This processor directs all

 

functions of the controller including command processing, PCI and SCSI bus transfers, RAID

 

processing, drive rebuilding, cache management, and error recovery.

Cache Memory Cache memory resides in a single 64-bit DIMM socket that requires one X8 or X16 unbuffered 3.3V SDRAM single-sided or double-sided DIMM. Possible configurations are 16, 32, 64, or 128 MB.

MegaRAID supports write-through or write-back caching, which can be selected for each logical drive. MegaRAID does not use read-ahead caching for the current logical drive. The default setting for the read policy is Normal, meaning no read-ahead caching. You can disable read-ahead caching.

Warning!

Write caching is not recommended for the physical drives. When write cache is enabled,

loss of data can occur when power is interrupted.

MegaRAID BIOS The BIOS resides on a 1 MB or 2 MB × 8 flash ROM for easy upgrade. The MegaRAID BIOS supports INT 13h calls to boot DOS without special software or device drivers. The MegaRAID BIOS provides an extensive setup utility that can be accessed by pressing <Ctrl> <M> at BIOS initialization. MegaRAID Configuration Utility is described in the MegaRAID Configuration Software Guide.

Onboard Speaker MegaRAID has an onboard tone generator for audible warnings when system errors occur. Audible warnings can be generated through this speaker. The audible warnings are listed on page 125.

Serial Port MegaRAID includes a 9-pin RS232C-compatible serial port berg connector, which can connect to communications devices and external storage devices.

SCSI Bus MegaRAID Enterprise 1600 has four 160M Wide SCSI channels that support low voltage differential SCSI devices with active termination. Both synchronous and asynchronous devices are supported. MegaRAID provides automatic termination disable via cable detection. Each channel supports up to 15 wide or seven non-wide SCSI devices at speeds up to 160 MB/s per SCSI channel. MegaRAID supports up to six non-disk devices per controller. The SCSI bus mode defaults to LVD for each SCSI channel. If a single ended device is attached to a SCSI channel, MegaRAID automatically switches to SE mode for that SCSI channel.

SCSI Connectors MegaRAID has two types of SCSI connectors:

•two 68-pin high density internal SCSI connectors (Channels A and B only)

•four 68-pin external ultra-high-density external SCSI connectors (Channels A, B, C, and D) Cont’d

30MegaRAID Enterprise 1600 Hardware Guide