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Re: MS-DOS runs on Apple IIe

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Here's his earlier article with some info on the 8088 card:
https://sethkush.com/post/2026/03/12/ms-dos-2.0-on-the-apple-iie/

I’ve been porting MS-DOS 2.0 to the Apple IIe using the AD8088 Plus
coprocessor card. It’s an 8088 CPU on an expansion card with its own RAM and
ROM. The card shipped with CP/M-86, available from nanja.info. The original
ALF advertising materials suggest there may have been an MS-DOS port at some
point (they write about it in future tense, so I don’t know if it ever
actually happened), but the original OS disks aren’t shared to any of the
usual places. I decided to start my own port because I like directories and
object-oriented Turbo Pascal, neither of which CP/M-86 supports. Today I got
it to boot.

[Photo of The AD8088 Plus card]

The card has 64KB on-board RAM at 00000-0FFFF, another 64KB at 20000-2FFFF,
512KB at 40000-BFFFF, and a 256KB ROM at C0000-FFFFF (only 4KB of which is
used by the firmware). The Apple II’s main memory is visible to the 8088 at
10000-1FFFF, and the two processors talk through a shared memory protocol:
the 8088 writes a command byte, signals the Apple II through an I/O port,
and waits.


There are some constraints. This will never run CGA/EGA/VGA graphical
programs, and probably won’t ever run text programs that write directly to
VRAM. It does have full access to the 6502 address space though, so it could
in theory run MS-DOS programs with Apple II graphics. I’m pretty sure none
exist yet.

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Thread

MS-DOS runs on Apple IIe D Finnigan <dog_cow@macgui.com> - 2026-03-30 19:12 +0000
  Re: MS-DOS runs on Apple IIe D Finnigan <dog_cow@macgui.com> - 2026-03-30 19:14 +0000
  Re: MS-DOS runs on Apple IIe Steve Nickolas <usotsuki@buric.co> - 2026-03-31 17:08 -0400
    Re: MS-DOS runs on Apple IIe D Finnigan <dog_cow@macgui.com> - 2026-04-01 12:37 +0000
      Re: MS-DOS runs on Apple IIe Steve Nickolas <usotsuki@buric.co> - 2026-04-02 20:03 -0400

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