On Tue, 1 Oct 2002, Voyager wrote:
> Please correct me if I am wrong, but on the IBM PC motherboard there should
> be some jumpers or a dip switch array. Am I wrong? could anybody provide me
> with the functionality of these jumpers or switches?
On the PC, there are TWO switch packs. One for memory size, and one for
various option, including number of drives, 8087 installed, etc.
On the XT, there is ONE switch pack, and memory is determined during POST.
Int 11h maps the switches into AX.
Int 12h reports the amount of RAM.
1, 7, 8 are the number of drives
2 is co-processor (half are set wrong)
3, 4 is RAM on motherboard
5, 6 is monitor type
--
Grumpy Ol' Fred cisin_at_xenosoft.com
Received on Tue Oct 01 2002 - 15:39:01 BST