[Datrix Solutions <datrix@is.co.za> writes:]
>What does the init_mem() function in /vsta/os/mach/init.c accomplish?
>What is IO Port 0x64?
When IBM made the AT, it had more address space. To make the machine more
backward compatible, they disabled the extended address by default. They
had a spare output on the keyboard controller, so they hooked the high
address enable onto it. Like the comment in the file says: brilliant.
>Can anyone recommend a good reference for these hardware tricks?
IBM published an AT hardware reference manual. I don't know if you can lay
hands on it any more. I actually wrote VSTa with just my XT technical
reference guide, plus hints from the 386bsd source.
Andy Valencia
Received on Thu Nov 23 09:20:24 1995
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