IBM EXP15 Hardware Maintenance Manual

Also see for EXP15: Installation and User Handbook

SCSI bus and ID settings: When you install adrive CRU in the expansion unit, the drive tray plugs into aprinted circuit board called the midplane. The midplanesets the SCSI bus number and ID automatically, based onthe setting of Option Switch 1 and the physical location(bay) of the drive CRU.Your expansion unit supports up to two external SCSIbuses and up to two internal SCSI buses. Each internalSCSI bus uses five SCSI IDs. When you install theexpansion unit, you can set Option Switch 1 on the ESMboard to create two separate five drive SCSI buses, or youcan leave it set as one, daisy-chained ten drive SCSI bus.Option Switch 1 set to Off:With this default setting, all 10 disk drive bays are ona single SCSI bus. The midplane will assign theSCSI IDs for the drive bays in ascending order fromleft to right (rack mode) or from top to bottom (towermode) as follows:, 1, 2, 3, 4, 8, 9, 1 , 11, 12. Thesystem-management SCSI accessed fault tolerantenclosure (SAF-TE) processor uses SCSI ID 15.When Option Switch 1 is set to the Off position, youcan use either external cable connector.Option Switch 1 set to On:When Option Switch 1 is set to the On position, twoindependent internal five drive SCSI buses arecreated. External SCSI Bus 1 maps to internal SCSIBus 1 and external SCSI Bus 2 maps to internal SCSIBus 2. The midplane assigns the five internal Bus-1bays SCSI IDs , 1, 2, 3, and 4; and the fiveinternal Bus-2 bays SCSI IDs , 1, 2, 3, and 4. Oneach SCSI bus, the system-management processoruses SCSI ID 15.Important information:If you are using a ServeRAID software version earlierthan Version 3.50, the View Configuration screensmight show SCSI IDs or bay numbers. If the datashown on the View Configuration screen begins with'0', it denotes SCSI IDs. If the data shown on theView Configuration screen begins with '1', it denotesbay numbers.Rack and tower mode settings: Option Switch5 on the ESM board is the rack and tower mode switch.Switch 5 must be in the Off position when the unit isplaced in a rack and in the On position if the unit is placedin a tower. When shipped, Option Switch 5 is set to therack (Off) position.When Option Switch 5 is in the On position, two changesto your expansion unit will occur. First, the SCSI IDNetfinity EXP200 Type 3530 49