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    SubjectRe: Problems with to large of a kernel
    Followup to:  <>
    By author: "Richard B. Johnson" <>
    In newsgroup:
    > BzImage kernels use the BIOS INT 0x15 'memory copy' function to put
    > the kernel at its final resting place of offset 1 megabyte which
    > is unreachable in the 16-bit segment:offset world. Since this function
    > is enabled and tested by the BIOS as part of the memory check, it is
    > not too likely that it is broken. There was a problem with stuck
    > A-20 bits in early '386 machines that used the keyboard controller
    > to enable it. Basically, you had to wait a few microseconds to have
    > it take affect, since the keyboard controller is really its own CPU
    > with embeded software that takes time to do its thing. A BIOS would
    > certainly "know" the time to wait, so it would be embeded in the
    > INT 0x15 code. The problem occurs when a user program tries to enable
    > the bit and expects an instant response.

    Ah, yes; if the INT 15h memory copy function wasn't so bloody broken
    it might actually be usable. *Sigh* It was of course too much IQ
    required for anyone to have defined an A20 on/off BIOS function.

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