storage arrays (HSZ70 and HSZ80), or RA8000 or ESA12000 storage arrays (HSZ80 and HSG80). Older,
•UltraSCSI drives and fast wide drives can be mixed together in an UltraSCSI BA356 shelf (see Chapter 9).
•Differential UltraSCSI adapters may be connected to either (or both) a
•The HSZ70 and HSZ80 UltraSCSI RAID controllers have a wide differential UltraSCSI host bus with a Very High Density Cable Interconnect (VHDCI) connector. HSZ70 and HSZ80 controllers will work with fast and wide differential SCSI adapters (for example,
•Fast, wide SCSI drives (green StorageWorks building blocks (SBBs) with part numbers ending in
•Do not use fast, narrow SCSI drives (green SBBs with part numbers ending in
•The UltraSCSI BA356 requires a
•An older BA356 that has been retrofitted with a
3.2SCSI Bus Performance
Before you set up a SCSI bus, it is important that you understand a number of issues that affect the viability of a bus and how the devices connected to it operate. Specifically, bus performance is influenced by the following factors:
•Transmission method (Section 3.2.2)
•Data path (Section 3.2.3)
•Bus speed (Section 3.2.4)
3.2.1SCSI Bus Versus SCSI Bus Segments
An UltraSCSI bus may comprise multiple UltraSCSI bus segments. Each UltraSCSI bus segment comprises electrical conductors that may be in a
Shared SCSI Bus Requirements and Configurations Using UltraSCSI Hardware