9-4 Dell PowerEdge 6100/200 System Installation and Troubleshooting GuideMost interface connectors are keyed for correct insertion;that is, a notch or a raised tab on one connector matches atab or notch on the other connector. Keying ensures thatthe pin-1 wire in the cable (indicated by the colored stripalong one edge of the cable) goes to the pin-1 ends of theconnectors on both ends.DC Power CablesEach drive in the external drive bays must connect to a4-wire DC power cable from the system power supply orpower-supply paralleling board. The connectors on thiscable are labeled “FD1,” “FD2,” “FD3,” “FD4,” and“FD5.” Connectors FD1 through FD4 are used for5.25-inch devices, whereas connector FD5 is used for thestandard 3.5-inch diskette drive. Before connecting adrive to a power cable, refer to Figure 9-5 to identify thecorrect cable connector to use for the drive.Figure 9-5. DC Power Cable ConnectorsInstalling SCSI Devices in theExternal BaysSCSI devices in the external drive bay (such as CD-ROMdrives and tape drives) are controlled by the Ultra/WideSCSI controller on the system board.SCSI Configuration InformationAlthough SCSI devices are installed essentially the sameway as other devices, their configuration requirementsare different. To configure SCSI devices installed in theexternal bays, follow the guidelines in the followingsubsections.SCSI ID NumbersEach device attached to the Ultra/Wide SCSI host adaptermust have a unique SCSI identification (ID) numberfrom 0 to 7.When SCSI devices are shipped from Dell, the defaultSCSI ID numbers are assigned as follows:• The computer’s built-in Ultra/Wide SCSI hostadapter is configured through the basic input/outputsystem (BIOS) as SCSI ID 7.• A SCSI tape drive is configured as SCSI ID 6 (thedefault ID number for a tape drive).• A SCSI CD-ROM drive is usually configured asSCSI ID 5.NOTE: There is no requirement that SCSI ID numbers beassigned sequentially or that devices be attached to the cable inorder by ID number.Device TerminationSCSI logic requires that the two devices at opposite endsof the SCSI chain be terminated and that all devices inbetween be unterminated.Before installing SCSI devices in the computer, you mustconfigure the terminators on the SCSI device(s) to con-form to the following guidelines:• A single SCSI device (such as the standardCD-ROM drive) is terminated.CAUTION: When connecting an interface cable,do not reverse the interface cable (do not place thecolored strip away from pin 1 of the connector).Reversing the cable prevents the drive from oper-ating and could damage the controller, the drive,or both.system boardconnector5.25-inch driveconnector3.5-inch driveconnector
