SINIX is a discontinued variant of the Unix operating system from Siemens Nixdorf Informationssysteme.
SINIX supersedes SIRM OS and Pyramid Technology's DC/OSx.
Following X/Open's acceptance that its requirements for the use of the UNIX trademark were met, version 5.44 and subsequent releases were published as Reliant UNIX by Fujitsu Siemens Computers.
Each universe had its own command set, libraries and header files.
The original SINIX was a modified version of Xenix and ran on Intel 80186 processors.