In April, Microsoft published the code for its 1986 MS-DOS 4 operating system on GitHub. This is not the first release of DOS code, but this one seems to break some critical files.
As Michal Nekasek, a well-known developer and host of the OS/2 Museum blog, noted in his article «How not to open historical source code»The inability of git to save timestamps and conversion to UTF-8 breaks almost everything. Nekasek praised the code release, but criticized the bugs that arose in the process: «Please do not distort historical source code by shoving it into (stupid) git».
Of the two problems, the source files being converted to UTF-8 is the biggest. Older systems cannot parse UTF-8 and probably cannot be updated to do so either. The line length limit in bytes of MASM MS-DOS 4 was 512 bytes, and conversions to UTF-8 force strings to exceed this limit, making them unreadable.
The severity of the file errors varies, but the OS/2 Museum publication notes that the main system files are perfectly consistent with the original 4.00 release, which fixed several errors. It was not directly available, but it was shipped to computer manufacturers.
The original post recommended just releasing the raw files as an archive without UTF-8 conversion or anything like that. However, the story immediately continues in the comments, where MS-DOS 4 release co-developer Connor Hyde, aka Starfrost, acknowledges the problem and reveals the legal reasons for not including timestamps.
The discussion between Michal and Starfrost continues in the comments, and then they move it to emails. Despite Michal’s critical tone, it is noted that an indie developer like Starfrost is not to blame for the idiotic corporate policy of «obviously».
These problems are likely to be resolved in the near future so that MS-DOS 4 can work as before. However, MS-DOS 4 was not very popular because it used as much as 92 KB of RAM — a huge amount. Interestingly, at one time this led to the fact that the competitor DR-DOS completely skipped versions 4.0-4.99 in favor of moving from version 3.41 to version 5.0.
Source: Tom’s Hardware