This may just be a minor curiosity, considering how old and limited these old versions are, but I find it to be a neat little bit of historical domain to release the code for such.

Thoughts?

My first thought is that the link is wrong. I think you meant to use the following URL:
https://blogs.msdn.microsoft.com/commandline/2018/09/28/re-open-sourcing-ms-dos-1-25-and-2-0/

Anyway, I think this is great for those interested in computer history. It may not be something you would want to run in production, but it can be a good way to see how things evolved from the early days.

One fact that one might find interesting: DOS 1.x did not support subdirectories; everything had to be in the file system root. Subdirectories were not implemented until DOS 2.x.

It might be interesting if the source code for MSX-DOS (the DOS variant that the MSX used) could be released as well. (I note that the source code for Nextor, which is based off MSX-DOS was released earlier this year.) This way, one could compare the two similar operating systems, and would help people get a glimpse unto an often-forgotten (especially for those living in the US) piece of computer history. (Also, MSX-DOS 1 lacked subdirectories; testing with an emulator, I found that the DIR command would recognize them, but there was no way to access them. Maybe I could now try this with MS-DOS 1.25, and see if I get the same behavior.)

By the way, that brings up a question: If I want to try these old versions of MS-DOS out in an emulator, what emulator would be best for this purpose?

DosBox?

Or Bochs?

Or... VirtualBox?

Thank you, edit implemented.

My first thought was: "The used a 3½" disc medium?"
That's pretty radical for 1986. I guess they were looking to the future! (Poor B:\ drive, RIP. :)

edit: Oops, I was talking about MSX-DOS!
===
I was just trying to find some reference to the Microsoft DOS development blow-out. (Pretty sure it was DOS, not Windows, but I may have that wrong.) When they added 1000 developers to try to hurry it along, and the extra people made it take longer (coördinating the teams and managing the kernel to prevent regression errors, etc.)

.
Or PCem

That's great. Much like the recent browser discussions, I am sure there are people here still using msdos 1 and expecting gog to support it....

Well, of course. GoG is an official partner in computer archaeology. :)

PC DOS 2.0 was released on March 1983.
5¼" disk is much much more common at that time.
Early 3½" disk have very low volume and have various different standards.

Note: The word disk usually used as magnetic storage media, the word disc usually used as optical storage media.

Floppy, we called them.

This was news, like, thirty months ago. And I'm still waiting for open sourced MS-DOS 6.22 or no dice.

It was, but then they shelved it, and now they've unshelved it recently.

Quite. :) Your correction of my English is unnecessary, considering I was there at the time. I had twin 135mm (5¼") floppy drives on my Apple //e. ;)

In Australia, where I was then, and now again, we call them discs. Americans use the spelling based on the Classical Greek, terming them disks, whereas most of the rest of the world spelt it disc.*

When I was at university, my friends and I were toying with a PDP-11, which had 11-inch floppies. (I'm not sure what version of the PDP-11 that was, because DEC re-used the label a couple of times, IIRC.)

I remember we thought the Lisa was pretty impressive (probably because we couldn't afford one :/). It was ludicrously unrealistic, though, considering I also remember that Apple made their OS so large that it wouldn't fit on a single floppy — one had to swap out the first floppy to insert the second. (Hard discs were not cheap.)

* Classical Latin influenced spelling, reaching English via Norman French.

"Recently" still means a lot of weeks ago...

Should be 8-inch floppies.