TS-UGOS 4 (codenamed Sydney) is a graphical operating system developed and released by Theorysonic. It was released on May 11, 1991.


The development of TS-UGOS 4 began on April 25, 1989, thirteen days after the release of TS-UGOS 3.

New featuresEdit

  • Rounded taskbar.


See alsoEdit

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