Arx - A full, stand-alone RTOS: fully preemptive realtime kernel, POSIX thread library, multithread-safe standard I/O libraries, TCP/IP suite, VFAT file system, X11 R6 window system, user-level IO. By Real-Time OSs Lab, Seoul National University.

Chimera - Multitasking, multiprocessor OS with features of commercial realtime OSs; as fast as VxWorks, OS-9, VRTX, LynxOS; 10 times faster in some cases: interprocessor communication. VMEbus-based, supports C/C++, goal: support developing dynamically reconfigurable software for robotic and automation systems.

E.R.I.K.A. - Microkernel RTOSs and set of integrated tools to develop embedded realtime applications, made to support all architectures used in power train controllers in automotive industry. Kernels have 2 main layers: Kernel Layer, Hardware Abstraction Layer, HAL. [Open Source, GPL]

MaRTE OS - Realtime kernel for embedded uses, follows Minimal Real-Time POSIX.13 subset. Most code is Ada, but some C, assembly. Hardware access via Abstract Hardware Interface (HAL). Runs in cross development environment: PC Linux Host, bare 386 PC Target, Ethernet LAN link. [Open Source, GPL]

Mälardalen Real-Time Research Center - At the IDt (CS) Department, Mälardalen University, Sweden. Fine lists of projects, publications, and other documents. Home of Asterix Project: the real-time kernel for the final frontier.
Meta Description: [ Real-time systems, Safety-critical systems, Software engineering, Data communication, Embedded systems, Electonics, Mechatronics, Intelligent systems, Monitoring and Testing, Programming languages, Biomedicine ]

Ptolemy Project - Studies modeling, simulation, and design of concurrent, real-time, embedded systems. Focus: assembly of concurrent components. Key underlying principle: use of well-defined computation models that govern interaction between components.

Real-Time Mach - By Real-Time and Multimedia Laboratory, Department of Computer Science, Carnegie Mellon University. RT-Mach is a resource kernel, a kernel provides resource-centric services, which can then be used to satisfy end-to-end QoS needs.

Real-Time Mach NTT - Another version of Real-Time Mach, by NTT Laboratories. Contains RT-Mach kernel, FreeBSD 2.2.8 server, real-time shell, RT-Java, Hurd loader. Site has fine 'Getting Started' section: readme, release notes, installation, hardware, compatibility, troubles QA, contacts.

ReTiS Lab - Real-Time Systems Lab, St. Anna's School of Advanced Studies, Pisa, Italy; researches innovative algorithms, methods, tools to deal with time-dependent applications. Projects: E.R.I.K.A., HARTIK HArd Real TIme Kernel, S.Ha.R.K.
Meta Description: [ RETIS - Real-Time Systems Laboratory ]

RTG: Real Time Systems Group - University of Pennsylvania, Philadelphia. Goal: develop methods, tools, systems to facilitate designing and implementing reliable distributed RT systems. Current projects: developing specification and analysis methods for RT systems, probabilistic modeling and analysis, schedulability analysis, run-time monitoring/checking, RT wireless communication and hybrid systems.

RTOS-UH - Hard RTOS, by University of Hannover: mature (usable in real-world systems), compact, scalable from small embedded uses to big development workstations; Motorola-based (MC, MP); uses ISO 9001-2 (software development) as internal guideline, mostly programmed via RT high-level language PEARL90, DIN 66253-2.
Meta Description: [ Information server of the realtime operating system RTOS-UH ]

S.Ha.R.K. - Dynamic configurable kernel architecture to support hard/soft/non realtime use with interchangeable scheduling algorithms: fully modular in scheduling policies, aperiodic servers, concurrency control protocols; all not modular in most traditional OSs. Derived from HARTIK: HArd Real TIme Kernel. [Open Source, GPL]

Spring Project - Realtime microkernel and integrated environment, designed and implemented to support/provide predictability, guarantees (on-line dynamic, atomic), end-to-end scheduling, resource reservations; supports call/task admission model; and multiprocessors.

SUMO - SUpport for Multimedia in Operating systems, Lancaster University: microkernel OS with facilities to support distributed realtime and multimedia applications and ODP-based multimedia distributed application platforms.

XOberon - Hard realtime OS for mechatronics, newest version for PowerPC; loosely based on Oberon OS, coded in Oberon-2. Goal: create framework for non-computer-scientists needing rapid application development (RAD) tool to program embedded systems.