4 ms·

Beyond the 1 MB barrier in DOS

• dang 3y ago
  Recent and related: How DOS was able to use most of the 1 MB address space of the 8086 - https://news.ycombinator.com/item?id=39031369 https://news.ycombinator.com/item?id=39031369 - Jan 2024 (71 comments)
  • jmmv 3y ago
    Yep! That one was the precursor to this other article... and there is one more in the pipeline :) I've tried to keep the scope of each one contained enough to keep the discussions more-or-less focused.
    • helf 3y ago
      [dead]
• hyperman1 3y ago
  I was hoping to learn some more of the digferences between VCPI and DPMI. My limited and probably wrong understanding was: EMM386 provided VCPI, while windows or a dos extender layered DPMI on top of that. I got the impression VCPI wanted to talk about individual 4K pages, and bigger memory allocations needed a for loop to modify each page individually, hence the multi second startup time of dos extenders: Give me 4k. Give me another 4k. And another 4k. And ...