

A collection of disassembled and commented source of parts of MS-DOS 1.0 - Audiophilip
https://github.com/mist64/msdos1

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WalterBright
DOS looks trivial to me these days. I kick myself for not going into business
making a workalike clone back then.

On a related note, I've kept most of my old machines, except (sadly) my H11.
They're just piled up in the basement. Last year I wondered what I had on
those old drives, and tried to turn on the computers. None of them would boot.
One made a popping sound and smoke came out.

My next attempt was to read the hard drives. My 286 drive wouldn't fit
anything modern. The oldest drive I could hook up was in the 486 box, and had
to try plugging it into many machines before the old IDE drive was recognized.
I was anxious to see what was on it.

Like opening old safes, turns out there was nothing much on it. I was
surprised at how simple my old programs were, and how small.

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mseepgood
Why disassemble when the original source code is available?
[http://www.computerhistory.org/atchm/microsoft-ms-dos-
early-...](http://www.computerhistory.org/atchm/microsoft-ms-dos-early-source-
code/)

~~~
jonsen
It is a tremendously giving exercise. I practically learned programming doing
that. Disassembling an entire MSDOS like operating system and then amending it
with print spooling, RAM disk, and the ability to run two tasks simultaneously
on special RAM bank switching hardware a.o. (But then we realised that the PC
with MSDOS would win and went on doing other more specialised things.)

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dezgeg
If you're interested in this kind of stuff, be sure to check the author's
(Michael Steil) blog: [http://www.pagetable.com/](http://www.pagetable.com/)
\- he has written all kinds of juicy blog posts about low level programming.

------
yuhong
PC-DOS 1.0.

