https://www.hanselman.com/blog/open-sourcing-dos-4 Scott Hanselman * about * blog * podcast * youtube * speaking [ ] [Search] browse by category or date Open Sourcing DOS 4 April 25, 2024 Comment on this post [12] Posted in Open Source Sponsored By Beta DOS DisksSee the canonical version of this blog post at the Microsoft Open Source Blog! Ten years ago, Microsoft released the source for MS-DOS 1.25 and 2.0 to the Computer History Museum, and then later republished them for reference purposes. This code holds an important place in history and is a fascinating read of an operating system that was written entirely in 8086 assembly code nearly 45 years ago. Today, in partnership with IBM and in the spirit of open innovation, we're releasing the source code to MS-DOS 4.00 under the MIT license. There's a somewhat complex and fascinating history behind the 4.0 versions of DOS, as Microsoft partnered with IBM for portions of the code but also created a branch of DOS called Multitasking DOS that did not see a wide release. https://github.com/microsoft/MS-DOS A young English researcher named Connor "Starfrost" Hyde recently corresponded with former Microsoft Chief Technical Officer Ray Ozzie about some of the software in his collection. Amongst the floppies, Ray found unreleased beta binaries of DOS 4.0 that he was sent while he was at Lotus. Starfrost reached out to the Microsoft Open Source Programs Office (OSPO) to explore releasing DOS 4 source, as he is working on documenting the relationship between DOS 4, MT-DOS, and what would eventually become OS/2. Some later versions of these Multitasking DOS binaries can be found around the internet, but these new Ozzie beta binaries appear to be much earlier, unreleased, and also include the ibmbio.com source. Scott Hanselman, with the help of internet archivist and enthusiast Jeff Sponaugle, has imaged these original disks and carefully scanned the original printed documents from this "Ozzie Drop". Microsoft, along with our friends at IBM, think this is a fascinating piece of operating system history worth sharing. Jeff Wilcox and OSPO went to the Microsoft Archives, and while they were unable to find the full source code for MT-DOS, they did find MS DOS 4.00, which we're releasing today, alongside these additional beta binaries, PDFs of the documentation, and disk images. We will continue to explore the archives and may update this release if more is discovered. Thank you to Ray Ozzie, Starfrost, Jeff Sponaugle, Larry Osterman, our friends at the IBM OSPO, as well as the makers of such digital archeology software including, but not limited to Greaseweazle, Fluxengine, Aaru Data Preservation Suite, and the HxC Floppy Emulator. Above all, thank you to the original authors of this code, some of whom still work at Microsoft and IBM today! If you'd like to run this software yourself and explore, we have successfully run it directly on an original IBM PC XT, a newer Pentium, and within the open source PCem and 86box emulators. About Scott Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author. facebook twitter subscribe About Newsletter Hosting By Hosted in an Azure App Service Comment on this post [12] Share on Twitter or Facebook or use the Permalink April 26, 2024 1:04 Did I miss it because I'm on my phone e, or is there no link to the source and downloads? [707d0fff7e] Paul April 26, 2024 1:13 https://github.com/Microsoft/MS-DOS here it is [61b2a0143b] starfrost April 26, 2024 1:59 This is wonderful stuff. I hope we can eventually get DOS 5 released - this was the first of the modern DOS's (DOS 5, 6.x being very similar), well getting the last ones would be good, I guess the drivespace thing may complicate things from the 6 side though. [177f75fab3] Stu April 26, 2024 3:04 @Stu The entire MS-DOS 6.22 source (along Windows 2000, NT, and bits of XP) were leaked a few years ago. They're still floating around the torrents and some websites. [5797e84418] Nobody April 26, 2024 4:39 @Nobody Actually it was an incomplete unbuildable 6.0 beta, not 6.22 [f66a4ff908] anonymous April 26, 2024 12:13 Why not simply release all MS-DOS source code up to the latest ones included with Windows 9x? Especially if 6.22 has leaked as a previous comment says. [3bebf09cb4] Hotdog April 26, 2024 13:52 wow.. but the problem is most of the developers are not able to understand source codes as they are written by GOD like developers. Is there any way to understand these codes what like what happens if I write a command and press enter? Sujit https://techsujit.com https://kaizen-apps.com [b9c63b2bc2] sujit Singh April 26, 2024 18:09 Learn! https://www.os2museum.com/wp/how-not-to-release-historic-source-code/ Read three times, maybe THEN you'll get it! [723e75e210] Steven April 26, 2024 18:46 Hello. Do you think that in the same open spirit, can the OS/2 source code be released? There is a small but still active OS/2 community that will benefit of that. On the other side the education value of an open source hybrid kernel like OS/2 with an important API set is also interesting. Regards [e34083be65] Martin Iturbide April 26, 2024 18:50 Thanks, Nobody - while I realise DOS and Windows code has been leaked I contribute to Free Software. Since I may one day contribute to Dosbox, DosEmu or Wine if I were to look at unofficially released source for DOS or Windows then that could influence me and I could end up contributing code I don't have the rights to, and cause a legal mess for those projects. I can look at the officially released code, and since DOS 4 is under MIT license, take that code and contribute it or things I find out by reading it to projects with compatible licenses. [177f75fab3] Stu April 26, 2024 18:59 Martini, are you stupid? While Arca Noae exploits that "OS/2 community" and produces ArcaOS, OS/2 source will be never released. [d79fb3392b] AlexT April 26, 2024 21:26 this is so funny. Scott praises archiving community, yet itself fails even to preserve timestamps and in the end ruins source code too. go back to school, "professor" [26014f97db] gray * Name [ ] Email [ ] (will show your gravatar icon) Home page [ ] (optional) 5+1=? 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