IBM 847651U Handbook - Page 168

Connecting external options Notes: If you plan to install both internal and external SCSI devices, you must follow the instructions given in "Installing or removing internal drives" on page 102 in addition to the instructions in this section. Read "Installing or removing internal drives"; then, return here. For additional information about SCSI configurations supported, see http://www.ibm.com/netfinity/ If your server comes with a SCSI adapter, it also comes with a wide (16-bit) SCSI cable that supports 16-bit devices. If you want to attach narrow (8-bit) devices to your server, you must purchase a SCSI 68-pin to 50-Pin Converter that will enable the connection of the device to the cable that comes with your server. It is good practice not to exceed the following cable-length guidelines: - If you connect one or more UltraSCSI devices to the UltraSCSI adapter, do not exceed 1.5 meters (5 feet) total length for all cables (internal and external). - If you connect only Fast SCSI devices to the UltraSCSI adapter, do not exceed 3 meters (10 feet) total length for all cables (internal and external). Attention: In addition to cable length and the number of installed devices, you must consider other factors that limit the performance of the SCSI subsystem. For example, if you install UltraSCSI devices in an external expansion enclosure that is limited to Fast transfer rates, or if you exceed the previously described cable-length guidelines, the transfer rate to all SCSI devices must be limited to Fast or standard transfer rates. You accomplish this by using the SCSISelect Utility program. See "Using the SCSISelect Utility program" on page 62 for additional information. If you plan to attach an external SCSI device, you must order an additional SCSI cable. That is, to use an external device with the Netfinity 3000 server, you must connect it to the external SCSI 134 Netfinity 3000 User's Handbook