Compaq AA-RHGWC-TE Server User Manual


 
9.1 Using SCSI Bus Signal Converters
A SCSI bus signal converter allows you to couple a differential bus segment
to a single-ended bus segment, allowing the mixing of differential and
single-ended devices on the same SCSI bus to isolate bus segments for
maintenance purposes.
Each SCSI signal converter has a single-ended side and a differential side as
follows:
DWZZA 8-bit data path
DWZZB 16-bit data path
DS-BA35X-DA 16-bit personality module
______________________ Note _______________________
Some UltraSCSI documentation uses the UltraSCSI "bus
expander" term when referring to the DWZZB and UltraSCSI
signal converters. Other UltraSCSI documentation refers to some
UltraSCSI products as bus extender/converters.
For TruCluster Server there are no supported standalone
UltraSCSI bus expanders (DWZZC).
In this manual, any device that converts a differential signal to
a single-ended signal is referred to as a signal converter (the
DS-BA35X-DA personality module contains a DWZZA-on-a-chip
or DOC chip).
A SCSI signal converter is required when you want to connect devices with
different transmission modes.
9.1.1 Types of SCSI Bus Signal Converters
Signal converters can be standalone units or StorageWorks building blocks
(SBBs) that are installed in a storage shelf disk slot. You must use the signal
converter module that is appropriate for your hardware configuration.
For example, use a DWZZA-VA signal converter to connect a wide,
differential host bus adapter to a BA350 (single-ended and narrow) storage
shelf, but use a DWZZB-VW signal converter to connect a wide, differential
host bus adapter to a non-UltraSCSI BA356 (single-ended and wide) storage
shelf. The DS-BA35X-DA personality module is used in an UltraSCSI BA356
to connect an UltraSCSI host bus adapter to the single-ended disks in the
UltraSCSI BA356. You could install a DWZZB-VW in an UltraSCSI BA356,
92 Configurations Using External Termination or Radial Connections to Non-UltraSCSI Devices