Small but mighty, 9Front's 'Humanbiologics' is here
Plan 9 is what the original creators of Unix, Ken Thompson and the late Dennis Ritchie, did next – abetted by Golang creator Rob Pike. Plan 9 builds upon Unix and C, but extends both in new directions. While Unix was originally written in assembly language on a PDP-7 minicomputer with 8k of memory and a Graphic II display, it was later rewritten in C for the PDP-11 with a huge 12k of RAM. (It used half of it for a RAMdisk.)
Generally known as just Plan 9, the OS first escaped from Bell Labs in 1992. While Unix was built on 1960s minicomputers with plain-text terminals, Plan 9 was designed for networked graphical workstations, and both are deeply embedded into its design. Its developers invented Unix's "everything is a file" mantra, but this time around they really leaned into it. In Plan 9's filesystem, you'll find lots of plain text files that in Unix and Linux are either special in some way, or aren't files at all. Instead of cryptic text editors and keystrokes, its much simpler shell assumes you can copy and paste with your mouse. (Although with the best will in the world, it is abundantly cryptic in its own right.)