Microsoft today announced that the MS-DOS 1.25 and 2.0 source code is available on GitHub, giving devs the chance to easily explore the early days of operating systems.

This is the second time the company rolls out the MS-DOS source code, after back in March 2014, Microsoft open-sourced the OS via the Computer History Museum.

However, this time Microsoft uses GitHub, the service that it purchased earlier this year, and which according to the software giant itself, should provide interested devs with a series of benefits, including easy access for existing GitHub users.

“Today, we're re-open-sourcing MS-DOS on GitHub. Why? Because it's much easier to find, read, and refer to MS-DOS source files if they're in a GitHub repo than in the original downloadable compressed archive file,” Microsoft’s Rich Turner explains.

Sama files as the 2014 version

The files published on GitHub are thus the same with the ones that were originally shared at the Computer History Museum. No modifications would be made, the company explains.

“The source files in this repo are for historical reference and will be kept static, so please don’t send Pull Requests suggesting any modifications to the source files, but feel free to fork this repo and experiment,” the repo readme notes.

“If, however, you’d like to submit additional non-source content or modifications to non-source files (e.g., this README), please submit via PR, and we’ll review and consider,” Microsoft further adds on GitHub.

Today’s announcement, which you can read here, also includes five different facts about MS-DOS, including stats about how the first versions of the operating system came to life. “The source code for the initial release of 86-DOS dates from around December 29th 1980,” one of them reveals – you can read the rest of them in the linked article.