I personely collect weird, crazy and curious operating systems and here you can finde some of them. Not all of them are real and some are total hoaxes but some are important for the history of operating systems and personal computers.
So let’s dive in into the Rabbit Hole!
| OS | NFO | Link |
| Red Star OS | National OS of North-Korea | 1 |
| JesOS™ | Unknown OS – no informations | 1 |
| TempleOS | Kind of religion OS by Terry A. Davis | 1, 2 |
| Muslim-OS | Linux based OS for muslim users. Similar to SabilyOS | 1 |
| UOS | National OS supported by Chinese authority | 1 |
| Kylin | OS developed by National University of Defense Technology China | 1 |
| Nova | National OS supported by Cuba’s authority | 1 |
| MOS | Soviet clone of Unix System | 1 |
| Astra Linux | National OS supported by Russian authority | 1 |
| AmigaOS | Native OS for the Commodore Amiga | 1 |
| Zamin OS | Not verified – National OS of Iran | 1 |
| NeXTSTEP | Hybrid OS from the 1980s and 1990s | 1 |
| UniOS | Fake/Hoax OS from a german student | 1 |
| MenuetOS | Lightweight OS written in assembly – It fits on a single floppy | 1, 2 |
| OpenVMS | Early OS from 1977 for VAX computers | 1 |
| Rodos | Real-time OS developed and used by the DLR | 1, 2 |
| VxWorks | Real-time OS used by NASA for the Pathfinder-Mission | 1, 2 |
| COS | Chinese national mobile OS developed by ISCAS | 1 |
| COS | Mysterious OS as an alternative for the Apple Mac | 1, 2 |
| COS | Native OS for supercomputer from Cray Research | 1 |
| BeOS | Also known as Media OS by Be Incorporated – 2001 sold to Palm, Inc. | 1 |
| OS/2 | Developed by IBM and Microsoft – original successor for DOS | 1 |
| Domain/OS | Native OS for Apollo/Domain workstations by Apollo Computer | 1 |
| Buddha OS | Unknown OS – no informations | 1 |
| Symbian-OS | Native OS for Nokia Phones and PDAs | 1 |
| Lisa OS | Native OS on Apple Lisa in 1983 | 1 |
Here is also a list of all Robotron operating systems. Unfortunately, there are too many of them.