Microsoft Just Released MS-DOS Source Code!

I love that they specify that they're not accepting pull requests.

The MS-DOS v1.25 and v2.0 files were originally shared at the Computer History Museum on March 25th, 2014 and are being (re)published in this repo to make them easier to find[.]

Ignore them. Send a pull request with the full source of Arch Linux.

LOL, some of the comments in the source are gold.

https://github.com/microsoft/MS-DOS/blob/main/v4.0/src/DOS/ABORT.ASM

Note:  We do need to explicitly close FCBs.  Reasons are as follows:  If we
; are running in the no-sharing no-network environment, we are simulating the
; 2.0 world and thus if the user doesn't close the file, that is his problem
; BUT...  the cache remains in a state with garbage that may be reused by the
; next process.  We scan the set and blast the ref counts of the FCBs we own.
;
; If sharing is loaded, then the following call to close process will
; correctly close all FCBs.  We will then need to walk the list AFTER here.
;
; Finally, the following call to NET_Abort will cause an EOP to be sent to all
; known network resources.  These resources are then responsible for cleaning
; up after this process.
;
; Sleazy, eh?~

i remember writing .bat files and pretending they were really fancy update scripts when i was like ten they did nothing but it was still fun :)

I guess we now have a timeframe in which to expect the release of Windows.

FreeDos is better anyways

MS-DOS, Source public available on March 25 2014 with MS Research License, released with as Free Software MIT license in 2018, this yer released as Open Source MS-DOS 4.0. Anyway, the Source code was available since 2014, only different licenses since then.

Take that FreeDOS!

Permanently Deleted

What's the use case that would upset Microsoft the most?

Look at them, embracing open source like this, how wonderful.

So cool, thanks. As a kid I spent so much time in DEBUG, stepping through DOS's executables, and especially the Interrupt handlers. It's so neat to see the actual source code-- way easier to read and follow. I didn't know it was all written in assembly, from within Debug it sometimes seemed so messy and convoluted that I just assumed more was written in C.

when rust

Where is the ctrl+alt+del function defined? I just want to see what made that sequence work. I'd also be interested in where ctrl+break is defined.

Woah MIT license. That’s a lot more permissive than I expected.

!remind 10 years when they will release the source code of Windows 3.0 for non-commercial use

(3.11 will take another 10 years)

Wake me up when they open source Windows 10/11.

Would this have Bill’s code in it ? Or was he off the shop floor by then ??

https://github.com/microsoft/MS-DOS/blob/main/v4.0/src/DOS/CTRLC.ASM
; The user has returned to us.
So ominous.
; Well... time to abort the user.
Goodbye

6.22 or foff

How much you wanna bet that a select few turbo-nerds are racing to debug it or something.

Is this useful for hobbyists besides poking around and seeking the design philosophy at work back then?

Like would there be any advantage or reason to implement this in a home project? For example maybe that it's lightweight and has some rare compatibility or anything like that?

MS-DOS 1.25, 2.0 were release years ago, your title should specify 4.0

Wake me when they release DOS 6.x source code.

Cough

If you want something actually useful

Did they use source control of any kind back then?

Ah, the Quick and Dirty Operating System.... we meet again.

So not 3? Why not, because it was the most successful or something? 🤷

Plus I never even heard of 4 before. I'm going to have to look that up.

Bah, I was thinking of windows. I need to get some sleep.

Too late.

https://en.wikipedia.org/wiki/ReactOS already exists

wasn't it leaked already

reminds me of the last time I had to remember that dir/copy/move with backslashes. dad's insurance 'software'. always amazed me how computer users get stuck in a way of doing things. print mail

not making money. make windows a gui on top of linux. like osX. silly microsoft

Who the hell writes stuff like this in asm, honestly? Hasn't C been around since like the 70s