RTEMS - Growing article, with links to many related topics. Wikipedia. - http://en.wikipedia.org/wiki/RTEMS
Joel's World - Personal page of Joel Sherrill, one of original authors, and current maintainer, of RTEMS; and R&D Director at OAR Corp. Much interesting material, useful links. - http://www.rtems.com/~joel/
Engineer's Office for Microcomputer Technology - Development, training, support services for embedded hardware and software, especially based on RTEMS RTOS; founded 1987. English, Deutsch. - http://www.imd-systems.de/
OAR: On-Line Applications Research Corp. - Parent firm for RTEMS RTOS, open source, free, no royalty, full source code; and GNAT/RTEMS Ada95 compiler system useful for cross development. Support, training, custom development; founded 1978. Alabama, USA. - http://www.oarcorp.com/
WebRing: RTEMS - Ring for this free real-time OS. Linked sites are somehow related to the OS, can be pages showing applications or products, research projects, and libraries ported to it. - http://d.webring.com/hub?ring=rtems
RTEMS Home - Real-Time Executive for Multiprocessor Systems. Runs on: AMD 29K; Hitachi SH; HP PA-RISC; ix86, i960; m683x0, m680x0, mPPC, mColdfire; MIPS R46x0, SPARC. Multiple APIs: RTEMS, POSIX-Unix, uITRON. Written in Ada, C/C++. [Open Source] - http://www.rtems.com/