Code For Microsoft's 1981 MS-DOS Now Available On GitHub

Microsoft has released the code for MS-DOS v1.25 v2.0, an operating system for x86-based personal computers and initially released in 1981 to GitHub. The reason is said to be to allow exploration and experimentation and to know about the history and rise of coding and developing.
Microsoft, MS-DOS 
Source- Github
One of the most interesting features of the version was that its way smaller than a typical web page, taking up only about 12KB of memory while still having ancillary files used by Seattle Computer Products (SCP), which made the original OS that Microsoft purchased and rebranded as MS-DOS meaning the actual operating system would be even smaller. It is also in assemble language and has clearly stated functions making it easy to read.
It is also a few million times shorter in terms of the number of the number of lines of codes than any recent Windows OS. The version is also written in a very low-level language, obviously, being written 35 years ago when the performance of systems along with memory and speed was way less developed.
Developers can go through the code on GitHub.