Table of Contents
Advertisement
Shadow
Software that resides in a read-only memory (ROM) chip on a
device is called firmware. The AwardBIOS permits shadowing of
firmware such as the system BIOS, video BIOS, and similar
operating instructions that come with some expansion peripherals,
such as, for example, a SCSI adaptor.
Shadowing copies firmware from ROM into system RAM, where
the CPU can read it through the 16-bit or 32-bit DRAM bus.
Firmware not shadowed must be read by the system through the 8-
bit X-bus. Shadowing improves the performance of the system
BIOS and similar ROM firmware for expansion peripherals, but it
also reduces the amount of high memory (640 KB to 1 MB)
available for loading device drivers, etc.
Enable shadowing into each section of memory separately. Many
system designers hardwire shadowing of the system BIOS and
eliminate a System BIOS Shadow option.
Video BIOS shadows into memory area C8000-DFFFF. The
remaining areas shown on the BIOS Features Setup screen may be
occupied by other expansion card firmware. If an expansion
peripheral in your system contains ROM-based firmware, you need
to know the address range the ROM occupies to shadow it into the
correct area of RAM.
58
MB-662 User Manual
Advertisement
Table of Contents
