Minor nitpick from what you’ve posted above (I’m sure you know this and perhaps had a brain fart when you posted):
GEM was DRs GUI so an alternative to Windows. Their DOS equivalent (in fact the predecessor to DOS technically speaking) was CP/M.
I do take your larger point though and thank you for the links. It was very informative. However that example aside, it’s still worth noting that Pascal was a popular language that fell out of favour in the 90s as C its derivatives swept through the industry. Now it seems uncool to have ALGOL-like syntax with languages either opting for C-braces or being whitespace driven like Python. And I see that as a loss in terms of readability.
I’m probably just sound old now though — moaning about “the good old days” lol
Windows 1.0 in 1985 was written in C Language and assembly. The x86 alternative os to MS-DOS such as Digital Research GEM was also written in C and assembly.
The Windows 16-bit ABI did have Pascal-style calling-convention for the stack but the OS was not written in Pascal: https://en.wikipedia.org/wiki/X86_calling_conventions#pascal....