M-Saunders writes: Fancy writing your own OS? The first official version of MikeOS has been released. It's a 16-bit PC OS written in assembly, released under a BSD-like license. It boots from floppy or CD, has 30+ system calls and features basic DOS
.COM program compatibility. Moreover, it's designed to teach to teach basic OS design and x86 assembly language, and the new Handbook includes a whole section on writing your own OS. Sure, you wouldn't write an OS in 16-bit asm today, but hopefully it's a useful starting point for novices.