These are a few sites I've come across in my travels. The quality level
varies a lot. In most cases,
the descriptions are provided from the webmaster from the specific site.
BOS is a 32 Bit OS written in assembler in 2001. No recent updates, but still available.
Assembler-only OS for 32-bit x86 processors.
of Operating Systems
A Review of Operating Systems, stressing on free, original, actively
Rocky Coast Free Board
Free Software tools for programmers, along with
all the links to other OS and programming Web sites.
Plurix Distributed Operating System
Plurix is a native high-speed OS for PC clusters. Java objects are kept
in a Distributed Shared Memory space (DSM) and are easily accessible
from authorized workstations. An optimistic transaction scheme coupled
with restartable transaction guarantees consistency of shared data structures.
- A Teachable Operating System
Topsy is a small (~20k machine code) multi-threaded micro kernel. It
is written in ANSI C and protects kernel threads from user programs.
It supports memory management, thread/process control and an IO and
driver subsystem. Communication and synchronization is implemented with
messages. Topsy runs on MIPS R3000 and i386 based machines. A simulator
written in Java is available.