Chapter 3 – SCSI Installation
3-9
BIOS Location Address
The BIOS requires 16K bytes in memory. This may be mapped in six loca-
tions from C8000H through DFFFFH. Define a location which does not con-
flict with other system devices.
Hardware Interrupt Enable
The hardware interrupts may be enabled or disabled. There is an incompati-
bility among the module's BIOS, DOS 4.0.1, and some CPU's BIOS. This
incompatibility causes the system to stop running during a SCSI boot opera-
tion. However, this is not a problem when the SCSI drive is not the boot de-
vice or when a DOS version other than 4.0.1 is being used. In situations
where DOS 4.0.1 has to be used and the SCSI drive has to be the boot de-
vice, interrupts may be disabled and the system will boot correctly.
BIOS Functionality
The BIOS will only support SCSI disk drives and will support a maximum of
two drives. The BIOS only recognizes target:LUN values of 0:0 and 1:0. If
there is one SCSI drive, assign its target number to 0:0. If there are two
SCSI drives, assign their target numbers to 0:0 and 1:0. The BIOS will not
recognize any drives with target numbers 2:0 and higher.
If there are two standard drives, the BIOS will not connect any SCSI drives.
However, if there is one standard drive, a maximum of one SCSI drive will
be connected by the BIOS. If there are no standard drives, the BIOS will
connect a maximum of two SCSI drives. Use the drivers to overcome these
limitations.
The BIOS will assign SCSI drives sequentially after the standard hard drive.
That is, if there is one standard drive and a SCSI drive, the standard drive
will be assigned to C: and the SCSI drive (0:0) will be assigned to D:. If
there are no standard drives and one SCSI drive, the SCSI drive (0:0) will be
assigned to C:. If there are no standard drives and two SCSI drives, the SCSI
drive (0:0) will be assigned to C: and the SCSI drive (1:0) will be assigned to
D:.
BIOS Booting Contentions
When a SCSI drive is assigned to C: and there is no floppy diskette installed
in A:, the BIOS will attempt to boot from the SCSI drive 0:0 assigned to C:.
If there is a diskette in A:, the system BIOS will attempt to boot from A:.
If a standard drive is assigned to C:, then the system BIOS will attempt to
boot from the standard drive and no attempt will be made to boot from the
SCSI drive.
Summary of Contents for XVME-976/202
Page 48: ......
Page 50: ...XVME 976 Adapter Module 4 4 2 Figure 4 1 Connector and Jumper Locations...
Page 72: ......
Page 84: ......