44 PCA-6157/6157L User's Manual
a maximum of eight SCSI hard disks via INT13. The number
controlled by the SCSI BIOS depends on the number of
non-SDMS controlled disk drives in the system. For more infor-
mation on SCSI BIOS control of hard disk drives, see Device
Drivers for Windows Section.
SCSI Device Drivers
The SCSI device drivers translate an operating system I/O request
into a data structure, and transport the structure to the SCSI BIOS
(see above figure). An NCR SCSI device driver is operating
system specific, but completely hardware independent. The
hardware specifics are addressed by the SCSI BIOS.
Although a driverless solution exists for the DOS operating
system, and provides adequate support for many applications,
loading a driver (or drivers in some cases) will provide additional
features. Connecting peripherals other than hard disk drives, for
example, requires loading the appropriate driver(s).
The following Sections provide information on the use and
installation of these drivers within each operating system.
SDMS Information Flow
Operating System
SCSI Bus
SCSI Peripherals
NCR Controller or Processor
SDMS SCSI BIOS
SDMS Driver
