MS-DOS has been Open-Sourced! We Build and Run it!
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Microsoft has released the code to MS-DOS 4.00 on GitHub; Dave takes you a tour of the code, builds it, and runs it on original hardware. For my book on lif...
  • TimeSquirrel@kbin.social
    0·
    5 months ago

    Wonder what the reason was for so much being in raw assembly when C existed. A basic library/API would be one of the first things I’d tackle in an OS. Move on to a higher level as soon as you’re able.

    • AggressivelyPassive@feddit.deEnglish
      0·
      5 months ago

      Because Ryan wrote it like this 10 years ago and nobody bothered to rewrite it in C.

      Back then, I’d guess most developers were relatively fluent in assembly, so if there’s only a small change to make, they’d just change the assembly and move on.

    • davidgro@lemmy.worldEnglish
      0·
      5 months ago

      C compilers (at least on personal computers) weren’t great at optimization back then and every kilobyte mattered - the user only got 640 of them, going beyond that required jumping through hoops.
      Similar for MHz, hand optimization was important for performance since there was so little CPU time to go around.

    • palordrolap@kbin.social
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      5 months ago

      Compilers were much less complex back then and didn’t do a great deal of optimisation. Also hardware was slow, so your compiled code, which wasn’t necessarily optimal either before or after the compilation phase, was at least half as fast as you wanted it to be.

      If you wanted speed, you hand-rolled assembly.

  • ConfusedPossum@kbin.social
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    5 months ago

    What are the consequences of this

    Like does this mean they could develop an app where you just have a library with all those nostalgic legacy games

    • moody@lemmings.worldEnglish
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      5 months ago

      Very little. Older versions had already been open-sourced previously. This is specifically version 4.0, and the last version released was 8.0.

      • davidgro@lemmy.worldEnglish
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        5 months ago

        Technically correct, but 7 and 8 were part of Windows 9x.
        The last standalone version was 6.22

    • lemmyvore@feddit.nlEnglish
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      5 months ago

      DOS wasn’t a very complex OS and has already been reverse engineered more or less completely. Apps like DosBox already exist. It might cause a couple of minor revelations if/when the source is finally opened but I doubt it will have a big impact.