Scsi Cabling Requirements; Setting Scsi Ids; Scsi Connector Pin-Number Assignments - IBM eserver xSeries 350 User Reference Manual

SCSI cabling requirements

If you plan to attach external SCSI devices, you must order additional SCSI cables. To
select and order the correct cables for use with external devices, contact your IBM
reseller or IBM marketing representative.
For information about the maximum length of SCSI cable between the terminated
ends of the cable, refer to the ANSI SCSI standards. Adhering to these standards will
help ensure that your server operates properly.

Setting 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. The following table lists the SCSI IDs for devices that are connected to one
channel. Note that the hot-swap hard disk drive bay numbers are from bottom to top.
The hot-swap-drive backplane controls the SCSI IDs for the internal hot-swap drive
bays. However, when you attach a SCSI device to the external SCSI connector, you
must set a unique ID for the device. Refer to the information that is provided with the
device for instructions to set its SCSI ID.

SCSI connector pin-number assignments

The following table shows the pin-number assignments for the 68-pin SCSI
connectors.
Pin
1 +Data 12
2 +Data 13
3 +Data 14
4 +Data 15
68
IBM® xSeries 350: User's Reference
Standard
Drive bay 1: Drive bay 4:
SCSI ID 0 SCSI ID 12
Drive bay 2: Drive bay 5:
SCSI ID 1 SCSI ID 13
Drive bay 3: Drive bay 6:
SCSI ID 2 SCSI ID 14
Backplane: SCSI Backplane: SCSI
ID 8 ID 9
34
68
Table 11. 68-pin SCSI connector pin-number assignments.
Signal Pin
35
36
37
38
Table 10. SCSI IDs for hot-swap hard disk
drives and backplanes.
Optional
1
35
Signal
-Data 12
-Data 13
-Data 14
-Data 15