It's part of the legacy of an educational operating system from 1987 that initially targeted 8086 systems with 640 KiB memory and two 360 KiB floppy drives. The

It's part of the legacy of an educational operating system from 1987 that initially targeted 8086 systems with 640 KiB memory and two 360 KiB floppy drives. The teaching focus was deemphasized after the release of MINIX 3.1.0, so the system did gain features like VFS and paged virtual memory after that. There was an early version in the 3.1.x era that had experimental SMP support in the form of a BKL, but it has bit-rotten a long time ago. Alas, the microkernel never received the rewrite it needed to bring it into the 21st century. That is not to say that MINIX ever was just a toy OS, it was self-hosted from the first publicly released version if I'm not mistaken. But it takes much, much more than that to be a daily use OS nowadays.