RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open sourcereal-time operating system designed for embedded systems. It has been ported to various target processors (ARM, i386, m68k, MIPS, PowerPC, SH, etc). RTEMS is designed to support various open API like POSIX and uITRON. FreeBSDTCP/IP stack and various filesystem are also supported. OAR Corporation is currently managing the RTEMS project. RTEMS is used by some EPICS sites. Open source refers to projects that are open to the public and which draw on other projects that are freely available to the general public. ... A real-time operating system (RTOS) is an operating system that has been developed for real-time applications. ... An embedded system is a special-purpose computer system, which is completely encapsulated by the device it controls. ... FreeBSD is a Unix-like free software operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through 386BSD and 4. ... The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet runs. ... The Experimental Physics and Industrial Control System (EPICS) is a software environment used to develop and implement distributed control systems to operate devices such as particle accelerators, telescopes and other large experiments. ...