U s i n g t h e B I O S S e t u p U t i l i t y

ROM Shadowing

To shadow ROM means to copy its contents into the computer’s system or random-access memory (RAM). This is beneficial for two reasons: ROM has (relatively) long access times and the processor can access RAM faster than ROM; second, the contents of RAM can be cached for even greater performance. All of the computer’s system BIOS ROM is shadowed.

The ROM Shadowing option allows you to shadow video BIOS and up to three 32 Kbyte areas of expansion card ROM (that is, ROM fitted on ISA or PCI expansion cards) addressed between C8000h and EFFFFh.

See the chapter entitled “Adding Expansion Cards” for more information about addressing expansion card ROM.

Note that the two 32 Kbyte areas from E0000h to E7FFFh and E8000h to EFFFFh cannot be shadowed independently of the system BIOS ROM.

Caution

Shadowing is only appropriate for expansion card ROM. It must not be enabled for expansion card RAM.

PCI Settings

The only configurable PCI setting is Palette Snooping, which can be “Enabled” or “Disabled”. It should be enabled only for PCI video expansion cards that require it.

ISA Legacy Resources

After fitting an ISA expansion card in your computer, you should use this option to mark as “Not Available” those system resources that the card uses. This needs to be done because the BIOS cannot detect their being in use, but must know about them so as to automatically configure any “Plug and Play” devices and PCI cards to avoid resource conflicts.

There is a separate option for each resource: memory, I/O ports, DMA channels and interrupts. See the chapter entitled “Adding

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