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jmward01 2 hours ago [-]
It is rare that I say this but, thanks MS! Arguably just as, if not more, important is the BASIC that they wrote. That was what they actually wanted to do. DOS just got them the contract with IBM. For decades MS was really a developer tools company with a side biz of writing operating systems and other misc software. They also open sourced that BASIC code too [1].
wow, they had to OCR it back in from paper printouts
> This source code is old enough that it hadn’t been stored digitally. “A dedicated team of historians and preservationists led by Yufeng Gao and Rich Cini,” calling itself the “DOS Disassembly Group,” painstakingly transcribed and scanned in code from paper printouts provided by Paterson. This process was made even more difficult because modern OCR software struggled with the quality of the decades-old printout.
FarmerPotato 2 hours ago [-]
I'd like to hear more about what works in OCR of dot-matrix fonts.
I've been able to OCR letter-quality printer output to 97% (mostly Os and Xs problems).
But it seems that machine-learning text-recognition is also now biased to reject computer code because it doesn't look like human language.
SoftTalker 3 hours ago [-]
Yet another case where text printed on paper outlived any digital storage.
jshier 2 hours ago [-]
Seems like it was never digitally stored in the first place, and the printed text was barely readable due to age. Not really a big win for paper.
SoftTalker 2 hours ago [-]
Well it had to have been on disk or tape at some point. It wasn't all typed in by hand every time they needed to build a new version.
zargon 2 hours ago [-]
The idea that it never existed digitally is obviously untrue. Likely poor wording in the author's part. They probably meant something like, so old that a printout is all that survived (which sounds vaguely like not being digital to someone in an era so far removed from a time when programs were/could realistically be printed.)
petcat 2 hours ago [-]
> struggled with the quality of the decades-old printout.
barely
It sounds like this printout has deteriorated badly and was barely readable.
I remember in the naughts, coming across a dos machine that was quite out of time… even for the university basement it was living in next to a pile of lead brick. Its only job was to run an instrument via an home-built ISA card and write data out to 5.25” floppies.
What uses would this code have in 2026?
FarmerPotato 2 hours ago [-]
To see what decisions they made.
Like any historical document. Aim to understand the people of the time.
userbinator 3 hours ago [-]
I wonder how long it'll be before they release the source for the earliest Windows versions. The fact that they still have the source for this very old DOS at least gives hope that they also do for old Windows.
protocolture 6 minutes ago [-]
I imagine its not far off. I get the impression they are almost done with windows as a platform.
GaryBluto 56 minutes ago [-]
The day they would make Windows 2000 codebase open source (or source available) would be the day I could die happy (although I'd probably be long dead anyways by the time there's a glimmerof chance of it happening). What a beautiful, smooth-running operating system it was.
londons_explore 41 minutes ago [-]
There is a mostly complete leak of it...
optymizer 28 minutes ago [-]
Agreed. It's still my favorite Windows version.
teamsolid 3 hours ago [-]
I am sure that there is a lot good material to take inspiration and learning even from the early Windows 3.11.
mycall 2 hours ago [-]
Do a deep dive into how OS/360 formalized to having DOS.
SoftTalker 3 hours ago [-]
/s ?
throwaway27448 2 hours ago [-]
They waited a couple decades too long for this to be of interest.
teamsolid 3 hours ago [-]
It is wonderful how early years of modern computing was brilliant. We treated machines as they really are: machines. Performance, creativity, science..., all possible to make a 386 machine work. Nowadays is all about libraries, virtualization, [bad] code over [bad] code over [bad] code..., I dont like it.
dhosek 2 hours ago [-]
I sometimes think that my mental model of a computer is still an Apple ][+ with 48K of RAM leads to my writing better code.
dooosss 2 hours ago [-]
Too little, too late.
signa11 3 hours ago [-]
in the words of mr. mitch-hedburg “here, you throw this away“
TedDoesntTalk 44 minutes ago [-]
He could have sold those printouts instead of giving them away.
froyooh 3 hours ago [-]
Back when it was all written by hand and optimized well.
[1] https://opensource.microsoft.com/blog/2025/09/03/microsoft-o...
Or on the GitHub clone (162 points, 15 comments) https://news.ycombinator.com/item?id=47946813
> This source code is old enough that it hadn’t been stored digitally. “A dedicated team of historians and preservationists led by Yufeng Gao and Rich Cini,” calling itself the “DOS Disassembly Group,” painstakingly transcribed and scanned in code from paper printouts provided by Paterson. This process was made even more difficult because modern OCR software struggled with the quality of the decades-old printout.
I've been able to OCR letter-quality printer output to 97% (mostly Os and Xs problems).
But it seems that machine-learning text-recognition is also now biased to reject computer code because it doesn't look like human language.
barely
It sounds like this printout has deteriorated badly and was barely readable.
Microsoft open sources DOS 1.00 on 45th anniversary - https://news.ycombinator.com/item?id=47957494 - April 2026 (19 comments)
I remember in the naughts, coming across a dos machine that was quite out of time… even for the university basement it was living in next to a pile of lead brick. Its only job was to run an instrument via an home-built ISA card and write data out to 5.25” floppies.
What uses would this code have in 2026?