227 pointsby DamnInteresting8 hours ago19 comments
  • jmward016 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].

    [1] https://opensource.microsoft.com/blog/2025/09/03/microsoft-o...

  • gnabgib8 hours ago
    Discussion, on the source, at the time (79 points, 24 days ago, 19 comments) https://news.ycombinator.com/item?id=47957494

    Or on the GitHub clone (162 points, 15 comments) https://news.ycombinator.com/item?id=47946813

  • okandship3 minutes ago
    readable plain text plus boring metadata still ages better than most clever archival systems
  • locusofself6 hours ago
    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.

    • FarmerPotato6 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.

    • WalterBrightan hour ago
      I've recovered some ancient software I wrote via scanning in listings I found among my dad's papers.
    • SoftTalker6 hours ago
      Yet another case where text printed on paper outlived any digital storage.
      • jshier6 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.
        • SoftTalker6 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.
          • debesyla2 hours ago
            unless they used punch cards
            • WalterBrightan hour ago
              I threw out all my punch cards. Wish I'd kept at least a listing!
            • andsoitis2 hours ago
              > unless they used punch cards

              For MS-DOS?

              • WalterBrightan hour ago
                Not likely. Punch cards disappeared around the end of 1976.
        • onion2k2 hours ago
          Early versions of some things, MS Basic being one example I think, were baked into ROM. One of the best innovations that Paul Allen came up with was adding software hooks to the code so bugs that were found later could still be patched.
        • zargon5 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.)
          • WalterBrightan hour ago
            Having printouts were necessary when:

            1. you were using a DECwriter dot matrix printer as a terminal

            2. using an ASR-33 teletype as a terminal

            3. using punch cards or paper tape

            4. using a glass tty that could only display 24 lines

            5. when you did not have a remote terminal, and wanted to spread your code out on a table and debug it

            • tankenmatean hour ago
              Brings back memories of desk checking
          • fc417fc8024 hours ago
            > a time when programs were/could realistically be printed

            Really depends on the program. Source code is often quite manageable. Even artifacts aren't always as large as you might expect. Busybox on my system weighs in at 1.9 MiB or alternatively 928 KiB with zstd maxed out.

            But I don't really see a point to printing any of it. A situation that might require the printouts is likely to largely preclude the continued existence of modern electronics, the ability to replace batteries, or even a connection to a reliable electrical grid.

            • zargon3 hours ago
              Yeah, that's why I tried to include both categories. Even for programs that are small enough to be printed, we just don't do it any more. I could have worded that part better myself.
        • irishcoffee4 hours ago
          How did they print it then, I wonder?
          • bryanrasmussen3 hours ago
            They had some old German guy with a big beard, and two interns, running some sort of big contraption that looked like a medieval torture instrument, and the interns would run and put letters in a row and then the old guy move a massive letter and in the end out came a bit of paper with source code on it.
      • petcat6 hours ago
        > struggled with the quality of the decades-old printout.

        barely

        It sounds like this printout has deteriorated badly and was barely readable.

  • dang8 hours ago
    Recent and related:

    Microsoft open sources DOS 1.00 on 45th anniversary - https://news.ycombinator.com/item?id=47957494 - April 2026 (19 comments)

  • userbinator7 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.
    • GaryBluto5 hours 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.
      • NitpickLawyer3 hours ago
        Wasn't there a 2000 source leak a while ago? I remember some exploits coming out after the leak.
      • optymizer4 hours ago
        Agreed. It's still my favorite Windows version.
      • londons_explore4 hours ago
        There is a mostly complete leak of it...
    • WalterBrightan hour ago
      It shouldn't be hard to disassemble it.
    • protocolture4 hours ago
      I imagine its not far off. I get the impression they are almost done with windows as a platform.
    • teamsolid7 hours ago
      I am sure that there is a lot good material to take inspiration and learning even from the early Windows 3.11.
      • mycall6 hours ago
        Do a deep dive into how OS/360 formalized to having DOS.
      • SoftTalker6 hours ago
        /s ?
        • AlecSchueler4 hours ago
          Pretty sure it's a bot or simple karma farming operation.
    • throwaway274486 hours ago
      They waited a couple decades too long for this to be of interest.
  • theanonymousonean hour ago
    I'm wondering whether ReactOS can exploit Claude et. al. to their fullest and "recreate" Windows 2000/95. I may donate some tokens for that cause.
    • leobuskin43 minutes ago
      I've used Claude to fix/reconstruct & build leaked Win2k3 on Linux with original toolchain via Wine. This approach included full gdi sources reconstruction. I just don't know what to do with this, it's kinda difficult to "wash" on this scale
    • CursedSiliconan hour ago
      That sounds like a terrifying legal minefield that they would not want to tread
  • teamsolid7 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.
    • dhosek6 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.
      • WalterBrightan hour ago
        While I did a few 10 line programs in BASIC in high school on punch cards, when things really started was a freshman class on semiconductors. The class started with diodes and quantum mechanics, then onto transistors, then flip flops, then registers, then ALUs. Then it was on to designing/building a digital clock (which never worked right), and later designing/building/programming single board computers (6802 chip).

        It was fun knowing everything about a computer. That's long gone!

      • stevesimmons2 hours ago
        And mine is a Commodore Vic-20 circa 1981, with 3583 bytes of free RAM. Programmed in 6502 assembler. Can't get much closer to the CPU than that.
    • aenis3 hours ago
      For a very long while now, we had programmers who never understood any low level concepts at all. They have started with js or python, and never looked 'down'. There are no limits to monstrosities they will consider normal.

      Linus Torvalds, a few months ago, said something to this effect when discussing AI coding tools. That his (also, mine) generation was lucky to have started with low level stuff and managed to retain the understanding of the whole stack - and kids these days don't get that. Good luck acquiring this level of feel for computers, algorithms, data structures today, when a kid's first experience with coding will be a seemingly genius chatbot.

      • charcircuit2 minutes ago
        >and managed to retain the understanding of the whole stack

        No one understands the whole stack. There is too much specialized information.

  • gnarlousean hour ago
    How about Microsoft fixes npm, github, and vscode
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  • imoverclocked6 hours ago
    Time to find vulnerabilities!

    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?

    • yjftsjthsd-h2 hours ago
      It's a single user OS that runs everything in ring zero by design. I'm not sure, definitionally, that it can have security vulnerabilities. I... guess maybe code execution on exposure to an untrusted floppy disk filesystem?
    • FarmerPotato6 hours ago
      To see what decisions they made. Like any historical document. Aim to understand the people of the time.
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  • froyooh7 hours ago
    Back when it was all written by hand and optimized well.
  • dooosss5 hours ago
    Too little, too late.
  • xuzhenpeng6 hours ago
    [flagged]
  • Tanayk074 hours ago
    [flagged]
  • signa117 hours ago
    in the words of mr. mitch-hedburg “here, you throw this away“
    • TedDoesntTalk4 hours ago
      He could have sold those printouts instead of giving them away.