Host InterfacesThe 2U library and the 4U library can be attached to servers using the followinginterfaces:v SCSI (LVD Ultrium 160)v Serial Attached SCSI (SAS)v Fibre ChannelTable 3-1. Host Drive Interface SupportDrive SCSI (LVD Ultra 160) SAS FCUltrium 3 FH X XUltrium 3 HH XUltrium 4 FH X* XUltrium 4 HH XNote: * = Dual Port SASSCSI InterfaceNote: Although the LVD hardware in the library is capable of operating insingle-ended (SE) mode, SE operation is not recommended.The library supports SCSI LVD attachments by using SCSI cables with 68-pin,HD-connectors. SCSI adapters must be properly terminated.Before installing the SCSI cables, inspect all cables for damage. Do not install acable if it is damaged. Report the damage immediately by contacting Dell customercare.The maximum allowable length of your bus cabling depends on the type of SCSIbus that you use (LVD).v For a server with an LVD SCSI bus:– Use a maximum system-to-device cable length of 10 m (33 ft) when attachingto the host interface board (SCSI) and one or two daisy-chained drives.– Use a maximum system-to-device cable length of 5 m (17 ft) when attachingto the host interface board (SCSI) and three to six daisy-chained drives.Note: For maximum performance, it is recommended to have a maximum ofone drive per SCSI bus.– Only use the maximum system-to-device cable length of 25 m (82 ft) whenattaching directly to one device (a point to point interconnection).Note: Daisy-chaining is NOT recommended due to potential issues with SCSIbus performance, SCSI cables/connectors, and host bus adapters.Physical Characteristics of the SCSI InterfaceThe library operates as a set of SCSI-3 devices. The Ultrium Tape Drives attach toservers using an LVD Ultra160 SCSI interface. Each SCSI drive sled uses shielded,HD68-pin connectors, and can attach directly to a 2-byte-wide SCSI cable.Any combination of up to two initiators (servers) and up to four targets (devices)is allowed on a single SCSI bus if the following conditions are met:Chapter 3. Installation Planning 3-7
