AT&T 3B2 Maintenance Reference Manual page 71

SCSI Bus Peripherals
Software
The SCSI Release 3 Host Adapter Utilities contain one software driver for both versions of the
host adapter cards. However, two pump files, scsil, and scsi2, are installed for the HAI
and HA2 cards, respectively. A new command, haversion(lM), can determine which type
of host adapter is in a particular
I/0
slot. The prtconf(lM) command can also distinguish
between the two types of host adapters.
A new feature of the software allows for shared peripherals when multiple hosts share a SCSI
bus (supported on HA2 only). 3B2 computers, as well as 3B4000 computers, may share
peripherals on a differential bus. For more information on shared peripherals, see Release 2 of
the SCSI Operations Manual, 305-012.
Disk Controller Module
The disk controller module (DCM) does the interface conversion between the SCSI bus and the
enhanced small disk interface (ESDI) bus of the disk modules. The DCM contains a SCSI
target controller, that supports up to four disk modules. The DCM is supported by the AT&T
3B2 SCSI disk Controller Utilities Software (described in the "Software" section of this chapter).
382 Peripheral Overview 3-11