Apertos
Object-oriented reflective OS, from Sony Computer Science Lab.

Object-Orientation in Operating Systems
By Rutgers University student. Concise introductory paper defines objects; OO OSs, filesystems, memory management; action-oriented versus OO programming; garbage collection in OO OSs in realtime context; some references, links.

ShagOS
Portable object-oriented microkernel OS, dynamically loaded device drivers, fully redesigned and rewritten many times in C++, runs on VAX, x86. Ongoing experiment in using O-O paradigm as framework for full OS, with distributed computing as main aspect in most design decisions.

Athene
Next generation, commercial, kernel independent, all object and component based computing environment and OS that users can design to their specifications. Backend is built to run in almost any environment. You Would also find info related to athene, object, oriented, open source, playstation, linux, amiga, windows, x11, alternative, xfree86, component, os, operating, system, multimedia and much more.

Iguana Project
Investigating use of object-orientation, computational reflection, and metaobject protocols (MOPs) to support dynamic customizing of (system) software.

Object-Oriented Operating Systems
Short, annotated, alphabetically sorted list and links, part of larger system.

QubeOS
Multiplatform desktop environment, supports 3 most common desktop OSs: DOS, Linux, Windows. Applications based and compiled for Qube run with no need to recompile on supported platforms, as machine code. Uses Object Routing (OR) methods; between object-oriented and structured programming.

Renaissance
Multiprocessor OO OS purely designed and implemented in object-oriented techniques, to give application programs transparent access to system and remote objects distributed in a network of machines. OO programming is an ideal approach for building distributed systems. Runs on Sun SPARC, Encore Multimax multiprocessor.

SOS: SOMIW Object-Oriented Operating System
Most interesting research results: simple, generic, powerful object model; the concept of Fragmented Objects to structure distributed abstractions; developed flexible naming service, dynamic linking package, library of application oriented communication protocols. You Would also find info related to SOS and much more.