IBM Eserver 345 Series, Руководство по установке опций

Страница: 53 / 70

Serial connector
Use a serial connector to connect a serial device. The following illustration shows a
serial connector.
1 5
6 9
Ultra320 SCSI controller system-board connectors
The integrated dual channel small computer system interface (SCSI) controller with
RAID capabilities 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 4 lists the SCSI IDs for the hard disk drives and
backplanes that are connected to one channel.
Table 4. SCSI IDs for standard hot-swap hard disk drives, 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
Chapter 3. Input/output connectors
41