4.10.6 SCSI Bus

The MegaRAID SCSI 320-2 controller has two Ultra320 Wide SCSI channels that support low voltage differential SCSI devices with active termination. Both synchronous and asynchronous devices are supported. The MegaRAID controller provides automatic termination disable via cable detection. Each channel supports up to 15 wide or seven non-wide SCSI devices at speeds up to 320 Mbytes/s per SCSI channel. The MegaRAID controller 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, the MegaRAID controller automatically switches to SE mode for that SCSI channel.

4.10.7 SCSI Connectors

The MegaRAID SCSI 320-2 has two types of SCSI connectors:

•Two 68-pin high density internal connectors

•Two 68-pin very-high-density external connectors

4.10.8SCSI Termination

The MegaRAID SCSI 320-2 uses active termination on the SCSI bus, conforming to Alternative 2 of the SCSI-2 specifications. Termination enable/disable is automatic through cable detection.

4.10.9 SCSI Firmware

The MegaRAID SCSI 320-2 firmware handles all RAID and SCSI command processing and also supports the features listed in Table 4.7.

Table 4.7 SCSI Firmware

Feature

Description

 

 

Disconnect/

Optimizes SCSI bus seek

reconnect

 

 

 

Tagged command

Multiple tags to improve random access

queuing

 

 

 

Scatter/gather

Multiple address/count pairs

 

 

4-10Features

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