TS-OS 3

TS-OS 3 is a graphical operating system developed and released by Theorysonic. It was released in 1977. When the TS-OS 3, along with TS-OS 4 and TS-OS 5 are unsupported by Theorysonic in 1996, TS-OS 3 was supported for 19 years by the time of the discontinuation, making it the longest-supporting operating system in Theorysonic computer industry.