NitrOS-9 is a real-time, process-based, multitasking, multi-user, Unix-like operating system for the TRS-80 Color Computer, Radio Shack Color Computer 2, Tandy Color Computer 3 and Dragon 64. The original OS-9 was created in 1979. NitrOS-9 is the modern equivalent of that OS, and includes advanced features like support for up to 2 MB RAM and 4 GB Hard drive partitions. It is still being developed, and support is available in many mailing lists and forums.

NitrOS-9 is a real-time, process-based, multitasking, multi-user, Unix-like operating system for the 6809 and 6309 processors. It runs on TRS-80 Color Computer, Radio Shack Color Computer 2, Tandy Color Computer 3 and Dragon 64. The original OS-9 was created in 1979. NitrOS-9 is the modern equivalent of that OS, and includes advanced features like support for up to 2 MB RAM and 4 GB Hard drive partitions. It is still being developed, and support is available in many mailing lists and forums.