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Linux/RT 1.1 adds priority inheritance support

May 31, 2000 — by LinuxDevices Staff — from the LinuxDevices Archive — views

Pittsburgh, PA — (press release) — TimeSys Corporation today announced an upgrade to the real-time features of TimeSys Linux/RT, a real-time version of the Linux Operating System. The additional features include: priority inheritance support within the kernel; TimeTrace support for detailed visualization of operating system internal events; and Rate-Monotonic Analysis-based (RMA) mathematical analysis… and simulation of real-time architectures via TimeWiz.

Linux/RT is an open-source Linux solution in which the Linux kernel has been extended to provide predictable real-time response, without adding a proprietary non-Linux RTOS as an abstraction layer between Linux and the system hardware. This approach eliminates the need for specialized real-time drivers or modifications to application software.

Priority inheritance avoids the unbounded priority inversion problem that frequently occurs in real-time system designs, and which leads to timing glitches in fielded products. For example, the NASA's Mars Pathfinder Rover mission in 1997 nearly failed due to unbounded priority inversion, but was saved by a single-bit correction uploaded to its software to enable priority inheritance. The story of the Mars Pathfinder has been widely distributed on the Internet and is available here. The original contributors of the techniques to address this problem include Dr. Raj Rajkumar, cofounder and chairman of TimeSys, and Dr. Douglass Locke, vice president of technology of TimeSys.

“TimeWiz offers both Rate-Monotonic Analysis and discrete-event simulation, which provide a balanced and disciplined approach to system design. TimeTrace offers the detailed view of the time-critical operating system events and metrics that are necessary for successful application deployment,” said Locke.

The enhanced product is available for download or purchase from the company's Web site.

Related stories:
TimeSys announces availability of Linux/RT 1.0
New real-time Linux distribution breaks the mold

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