Specifications

Getting Started

Page 23

Memory Shadow Sub-menu

The term “shadowing” refers to the technique of copying BIOS

extensions from ROM into DRAM and accessing them from

DRAM. This allows the CPU to access the BIOS extensions much

more quickly and generally increases system performance if many

calls to the BIOS extensions are made. The Memory Shadow Sub-

menu is shown below.

Item Specific Help

F1 Help Select Item -/+ Change Values F9 Setup Defaults

ESC Exit Select Menu Enter Select Sub-Menu F10 Previous Values

<Tab>, <Shift-Tab>, or

<Enter> selects field.

Memory Shadow

System Shadow: Enabled

Video Shadow: [Disabled]

Shadow Memory Regions:

D000-D3FF: [Disabled]

DC00-DFFF: [Disabled]

D800-DBFF: [Disabled]

D400-D7FF: [Disabled]

C800-CBFF: [Disabled]

CC00-CFFF: [Disabled]

Figure 2-5. Memory Shadow Sub-menu.

The shadow regions should be used only if an ISABus card is

installed in the system that contains a BIOS extension (ROM)

although there is no effect on the system if a region is shadowed

that does not contain a BIOS extension. Note that each shadow

region in the setup menu is 16KB in size. Multiple shadow regions

may have to be enabled if the BIOS extension to be shadowed is

larger than 16KB.

Note: when shadowing a BIOS extension contained in the FBD, the

user must ensure that the same region is not shadowed in this menu.

The region selected in the BIOS extension shadowing menu

supersedes the region selected in this menu.