---
title: "Microsoft Open-Sources MS-DOS 4.0 Under MIT License"
url: https://daily.dev/posts/microsoft-open-sources-ms-dos-4-0-under-mit-license-f33a6akq1
source_url: https://daily.dev/posts/microsoft-open-sources-ms-dos-4-0-under-mit-license-f33a6akq1
type: collection
source: "Collections"
published: 2024-04-26T10:19:21.769Z
updated: 2025-09-03T02:13:04.498Z
tags: ["computing-history", "microsoft", "open-source"]
reading_time: 2
upvotes: 5
comments: 1
language: en
---

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# Microsoft Open-Sources MS-DOS 4.0 Under MIT License

**[Collections](https://daily.dev/sources/collections)** · 2 min read · 5 upvotes · 1 comments

## Summary

Microsoft and IBM have released the source code for MS-DOS 4.00, a historic milestone in computer history. The release allows developers and enthusiasts to explore the inner workings of this pioneering operating system. It also explores the relationship between MS-DOS 4.00 and IBM's OS/2 operating system. However, challenges may arise when using modern version control systems to manage historic source code.

## Content

Microsoft and IBM have recently released the source code for MS-DOS 4.00, one of the most significant milestones in computer history. This collaboration, made possible by the MIT license, allows developers and enthusiasts alike to delve into the inner workings of this pioneering operating system.

The release includes not only the source code itself but also binary files and original documentation, offering a comprehensive look into the development of MS-DOS 4.00. Written entirely in 8086 assembly code almost 45 years ago, this codebase holds immense historical value.

One of the interesting aspects explored in the release is the relationship between MS-DOS 4.00 and IBM's OS/2 operating system. This sheds light on the evolution of operating systems and their influence on each other.

However, it's important to note that the release of historic source code can come with challenges. Using git, a modern version control system, for managing such code may lead to complications. In this case, DOS 4.0 and DOS 5.0 are highlighted as important milestones.

Overall, the open-sourcing of MS-DOS 4.00 is a significant development for the tech community. It provides an opportunity for developers and history enthusiasts to explore the origins of modern computing and gain valuable insights into the evolution of operating systems.

## Community discussion

Top comments from developers on daily.dev.

**@rashidulhasan** · 1 upvotes

> Repository URL: https://github.com/microsoft/MS-DOS

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---

Tags: [#computing-history](https://daily.dev/tags/computing-history), [#microsoft](https://daily.dev/tags/microsoft), [#open-source](https://daily.dev/tags/open-source)

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