IBM PC XT/AT and memory holes

Discussion in 'IBM' started by Vimal, Aug 26, 2008.

  1. Vimal

    Vimal Guest

    I tried to find a copy of the original specifications document for the
    IBM PC XT/AT, but I wasn't able to. I wanted to know what was the
    memory map of the original IBM PC XT.

    I remember reading that the regions from 0xA000:0 till 0xFFFF:7FFF
    were reserved for something other than memory mapped IO.

    Did the concept of memory mapped IO exist in the PC XT at all?

    Thanks,
     
    Vimal, Aug 26, 2008
    #1
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  2. Vimal

    Cheers Guest

    Hi

    you might want to ask the question in comp.sys.ibm.pc.classic

    the memory hole you're referring too did exist , from memory, it was
    between 640k(base memory) -- (upper memory) 1024k, this address was
    reserved for other I/os such as mono graphic cards, bios, hd bios
    (rll,mfm)and others.....
     
    Cheers, Aug 28, 2008
    #2
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