KateOS is a free multitasking operating system targeted toward intermediate Unix users. It combines the most popular Open Source software with its own original solutions. KateOS has a simple yet fully functional and fully-featured TGZex package system which makes system administration and updating a breeze. KateOS also has a set of text-mode and graphical tools for system configuration, user-friendly text-mode and graphical installation systems, a unified PAM authorization system, and many more solutions which make system maintenance a lot easier while preserving the classical Unix structure of the system. The main foci of KateOS are efficiency, security, reliability, and low system requirements. Support for common multimedia is also included.