IBM 847651U Handbook - Page 144

Installing or removing internal drives SCSI drives (if your server model comes with a SCSI adapter) Note: If your server model comes with a SCSI adapter, the adapter is an IBM UltraSCSI adapter. The information in this SCSI section applies to an UltraSCSI adapter. If your server model does not come with a SCSI adapter and you or your dealer have installed a SCSI adapter, consult the documentation that comes with that adapter for information on SCSI devices. Then, proceed to "Preinstallation steps (all bays)" on page 112. Some drives have a special design called small computer system interface (SCSI). This design allows you to attach multiple drives to a single connector. Note: Any information about SCSI drives also applies to other SCSI devices, such as scanners and printers. Your Netfinity 3000 server supports drives that comply with American National Standards Institute (ANSI) SCSI Standards X3.131-1986 (SCSI), X3.131-1994, (SCSI-2), X3.277-1996 (SCSI-3 Fast-20 parallel interface), and X3.253-1995 (SCSI-3 parallel interface). For a complete list of the SCSI devices that your server supports, go to http://www.ibm.com/netfinity/ on the World Wide Web. SCSI physical unit numbers (PUNs) When more than one physical device is connected to the same UltraSCSI adapter, the devices compete for support from the UltraSCSI adapter. Because the UltraSCSI adapter communicates with only one device at a time, the priority of a device is based on its SCSI identification (ID). The highest priority IDs are 7 to 0; the lowest priority IDs are 15 to 8. If you install additional SCSI devices, you must set a unique ID for each SCSI device that you connect to the integrated SCSI-2 connector. This unique ID enables the UltraSCSI adapter to identify the devices and to prevent two devices from sending or receiving data on the SCSI bus at the same time. SCSI devices use a variety 110 Netfinity 3000 User's Handbook