USU (operating system) of USU includes a very long list of educational apps, like as Celestia space simulator, MuseScore music score typesetter, Blender 3D rendering software, Kalgebra mathematical calculator, and much more. USU haves this approximate system requirements: USU (operating system) USU linux (Bulgarian: УСУ; Учи Свободен с Убунту) is Bulgarian open source desktop operating system built around the KDE desktop environment and based on the popular free Linux distribution, Ubuntu. Usu can be downloaded in three flavours, Desktop, Mini and Netbook, each one with its own features and target audience. All of them can be downloaded for free, as Live CD/DVD ISO
Cray Operating System 1.17 is available at archive.org. Cray Operating System The Cray Operating System (COS) succeeded Chippewa Operating System (shipped with earlier computer systems CDC 6000 series and CDC 7600) and is Cray Research's now discontinued proprietary operating system for its Cray-1 (1976) and Cray X-MP supercomputers, and those platforms' main OS until replaced by UNICOS in the late 1980s. COS was delivered with Cray Assembly Language (CAL), Cray FORTRAN (CFT), and Pascal. As COS was written by ex-Control Data employees, its command language and internal organization bore strong resemblance to the SCOPE operating system on the CDC 7600 and before that