IBM eServer xSeries 345 Type 8670, Maintenance Manual

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Ultra320 SCSI controller system-board connectors
Your server has an integrated dual channel small computer system interface (SCSI)
controller with RAID capabilities. This controller supports two independent Ultra320
SCSI channels: one external and one internal. Each channel supports up to 15
SCSI devices. You can use the external LVD SCSI channel connector on the rear of
your server to connect different types of SCSI devices, such as drives or printers.
This controller uses:
v
Double-transition clocking to achieve up to 320 MB-per-second data-transfer
rates
v Domain name validation to negotiate compatible data-transfer speeds with each
device
v Cyclic redundancy checking (CRC), instead of the usual parity checking, to
improve data reliability
v An active terminator for SCSI bus termination
The server comes with one SCSI cable, which connects the internal connector on
the system board to the standard hot-swap-drive backplane. If you plan to attach
external SCSI devices, you must order additional cables. To select and order the
correct cables for use with external devices, contact your IBM reseller or IBM
marketing representative.
SCSI cabling requirements
For information about the maximum length of SCSI cable, go to the American
National Standards Institute (ANSI) SCSI standards on the ANSI Web site at
http://www.ansi.org/ on the World Wide Web. Adhering to these standards will help
to ensure that your server operates properly.
SCSI IDs
Each SCSI device that is connected to a SCSI controller must have a unique SCSI
ID. This ID enables the SCSI controller to identify the device and ensure that
different devices on the same SCSI channel do not attempt to transfer data
simultaneously. SCSI devices that are connected to different SCSI channels can
have duplicate SCSI IDs. Table 9 lists the SCSI IDs for the hard disk drives and
backplanes that are connected to one channel.
Table 9. SCSI IDs for standard hot-swap hard disk drives, SCSI controller, and backplane
Device SCSI ID
Drive bay 1 0
Drive bay 2 1
Drive bay 3 2
Drive bay 4 3
Drive bay 5 4
Drive bay 6 5
SCSI controller 7
Backplane 8
The hot-swap-drive backplane controls the SCSI IDs for the internal hot-swap drive
bays. However, when you attach an external SCSI device to an optional SCSI
adapter, you must set a unique ID for the device. See the information that comes
with the device for instructions to set its SCSI ID.
Chapter 4. Customer replaceable units
75