DC/OSx (DataCenter/OSx) is a discontinued Unix operating system for MIPS based systems developed by Pyramid Technology. It ran on its Nile series of SMP machines and was a port of AT&T System V Release 4 (SVR4). In 1995, Pyramid Technology was acquired by Siemens Nixdorf Informationssysteme (SNI), and DC/OSx was superseded by the SINIX operating system.

OS X (pronounced "o-ess-ten"; originally Mac OS X) is a series of Unix-based graphical interface  operating systems (OS) developed and marketed by Apple Inc. It is designed to run on Macintosh computers, having been pre-installed on all Macs since 2002. OS X is the fourth most popular general purpose OS; within the market of desktop, laptop and home computers, and by web usage, OS X is the second most widely used desktop OS after Windows.