DolphinSamuel A. Falvo II's Dolphin is an OS for PC and compatibles; the project has been going for some time and has undergone several conceptual changes. Samuel has adopted a virtual machine scheme, where only a VM runs in ring 0 and all the rest of the system is implemented as ring 3 shared libraries (much like AmigaOS). These libraries use VM calls in order to access the underlying hardware. There is actual code floating around for this project, such as a bootsector that you can tune to boot your own protected mode OS. There seems to be actual progress this summer. Check all of that out from their homepage.
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