KURT: KU Real Time Linux
by University of Kansas (KU) Center for Research, Inc. Between a hard and soft real-time OS.

RTLinux: An Interview with Victor Yodaiken
RTLinux's main architect gives advice for budding computer scientists. [ACM Crossroads]

Finite State Machine Labs, Inc.: FSMLabs
Makes dual kernel RTLinux and RTCore/BSD, and OpenRTLinux RTOSs, realtime networking, protected memory, XML/RPC controls, embedded Linux developer kit; has RT developer tutorials and white papers; second tier support for Linux product vendors; software development, consulting (embedded, cluster, SMP).

Real Time Linux: Applications and Use
Brief treatment of embedded Linux uses. [LinuxWorld Today]

RTLinux.org
Hard realtime OS, runs Linux as its lowest priority execution thread, on Alpha, some MIPS, PPC, x86. News, downloads, applications, documents, mail list, projects.

TimeSys Corp.
Real-Time, Real Solutions. Home of TimeSys Linux/RT. Also Rate-Monotonic Analysis (RMA) based timing analysis and simulation. End-to-end real-time solutions.

RTLinux.com
Commercial home of this hard realtime OS, runs Linux as its lowest priority execution thread; for Alpha, some MIPS, PPC, x86; limited only by hardware. Contract work, custom development, board ports.

LinuxDevices.com: KURT: The KU Real-Time Linux
KURT introduction and analysis.

Team Takes Different Path to Real-time Linux
RTLinux doesn't try to change Linux into an RTOS, it instead provides a new RT kernel incorporating Linux as a low-priority thread, so the RTOS stays small, streamlined and keeps Linux as a base for common applications. [EE Times]

RTAI group
Real Time Application Interface: hard realtime support for Linux. Originally an RTLinux spinoff, but since redesigned and reimplemented from scratch. Intel only.

Linux, Real-Time Linux, & IPC
When dealing with realtime systems, IPC overhead becomes important; examines two of the best IPC mechanisms available for Linux: FIFO, shared memory. [Dr. Dobb's Journal]