Web site: sourceforge.net/projects/dolphin (not active)
Desktop environment: CLI
Based on: independent
The last version | Released: 1999 ?
Dolphin – an operating system for PC and compatibles, created by Samuel A. Falvo.
The project has been going for some time and has undergone several conceptual changes. The developer 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.