Let's investigate CP/M on my RC2014 Z80 based computer.
CP/M was an operating system before MS-DOS existed, and it requires surprisingly few resources to run. This computer runs at 7MHz and has 64K of RAM. CP/M itself fits into just 8K!
If you want the code for the Pascal Mandelbrot program, it's on this pastebin URL https://pastebin.com/ALGdMnbs
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https://www.youtube.com/watch?v=PAEgnbD0Z6g