Datasheet

Hot-Swap SCSI Backplane 1U Server Chassis SR1300

Revision 1.2

Intel order number A94544-004

6.3.6 SCSI Termination

Passive SE termination is used for the single-ended extension of the SCSI bus on which the

53C80S resides.

LVD/SE multi-mode terminators provide SPI-4 compliant active termination for the backplane

end of the SCSI bus. It is assumed that the other end of the SCSI segment is properly

terminated as required by the SPI-4 specification. Multi-mode termination is implemented on the

SR1300 hot-swap SCSI backplane using two Unitrode* UCC5638 multi-mode SCSI 15-line

terminators.

6.3.7 Power Control

Power control on the SR1300 hot-swap SCSI backplane supports the following features:

• Power-down of a drive when a failure is detected and reported (using enclosure services

messages) via the SCSI bus. This decreases the likelihood that the drive, which may be

under warranty, is damaged during removal from the hot-swap drive bay. When a new

drive is inserted, the power control waits a small amount of time for the drive to be fully

seated, and then applies power to the drive in preparation for operation.

• If system power is on, the hot-swap SCSI backplane immediately powers off a drive slot

when it detects that a drive has been removed. This prevents possible damage to the

drive when it is partially removed and re-inserted while full power is available, and

disruption of the entire SCSI array from possible sags in supply voltage and resultant

current spikes.

• Hot-spare drive support. Spare drives are kept in the hot-swap bay, but are left un-

powered until a drive is determined to have failed. In this case, the hot spare can be

powered up and put into service automatically without requiring immediate operator

intervention to replace the drive.

• The hot-swap SCSI backplane will automatically bypass the power control circuitry if a

shorted drive is inserted or if a drive develops a short during operation. This prevents

the hot-swap SCSI backplane from being damaged by a drive that draws excessive

current.

6.3.8 Drive Activity/Fault LEDs

Next to each hard drive connector is an Activity/Fault LED. The LEDs are activated by the

micro-controller and indicate either drive activity or a drive failure. The LEDs can be seen from

the front of the chassis by means of a light pipe mounted inside each hard drive carrier. During

initialization the micro-controller flashes the LEDs for one second as part of POST.

6.3.9 Internal Management Bus (IMB)

The IMB bus is a system-wide server management bus, based on the Phillips I

C bus

specification. It provides a way for various system components to communicate independently

with the standard system interfaces (e.g., PCI bus or processor/memory bus). The I

C bus

controller is integrated into the micro-controller. IMB connectivity is provided to the SCSI

backplane via the front panel connector.