Some related stuff:<p>In 2004, Gavin Barraclough’s mini-OS [0] won the IOCCC, packing a 32-bit multitasking operating system for x86 computers, with GUI and filesystem, support for loading and executing user applications in ELF binary format, with PS/2 mouse and keyboard drivers, VESA graphics, a command shell, and an application into 3.5 KB of highly obfuscated C code.<p>In 2021, Justine Tunney wrote SectorLISP [1], a Lisp implementation that fits into a bootsector and is able to run McCarthy’s metacircular evaluator.<p>[0]: <a href="https://www.ioccc.org/2004/gavin/index.html" rel="nofollow">https://www.ioccc.org/2004/gavin/index.html</a>
[1]: <a href="https://github.com/jart/sectorlisp">https://github.com/jart/sectorlisp</a>