For years, the Linux operating system has piqued the interest of embedded designers in virtually all areas, except those that require hard real-time performance.
Now that may be changing. The growing throngs of Linux faithful say that Linux's v2.6 kernel has all the real-time capabilities a designer could need, for applications from machine tools to telecom equipment.
"There's a reason why the adoption rate for Linux is growing so incredibly high," notes Larry Weidman, chief executive officer of TimeSys Corp., which distributes the Linux 2.6 kernel. "It's because everything you once wanted from your proprietary embedded operating system can now be obtained from Linux."
Still, there is disagreement in the Linux camp over how best to achieve real-time. While companies such as TimeSys employ the 2.6 kernel as their foundation, some competitors have employed other means. The following three companies offer real-time, open-source solutions.
LynuxWorks LynxOS alternative
A cornerstone philosophy at LynuxWorks, Inc. is that Linux is inherently non-real-time. The company therefore developed LynxOS, a real-time open-source operating system that conforms to the Linux standard and uses open application programming interfaces (APIs). The company says that each component in LynxOS is designed for "absolute determinism," meaning that the system unfailingly responds in a prescribed time period. LynxOS has been employed on the Army's Future Combat System. For moreinformation, go tohttp://rbi.ims.ca/4397-533.
TimeSys 'build-it-yourself' technique
The TimeSys Component Repository and Embedded Linux Platform Builder help developers build their own operating system atop a 2.6 Linux distribution. The Repository allows designers to select a version of Linux for their particular processor, and the Platform Builder directs them to real-time components that enable them to build, test, and certify their systems. In that sense, it's an improvement on the publicly-available Linux kernel because it optimizes the OS for the processor family and application. Notes Weidman of Timesys: "We provide developers with the ability, and believe that 90 percent of those developers want to build their own (system)." TimeSys' Linux RTOS has been employed on a Mars Exploration Rover vehicle designed by the Jet Propulsion Laboratory. For more information, go tohttp://rbi.ims.ca/4397-531.
FSMLabs dual-kernel approach
The FSMLabs RTLinuxPro 2.2 dual-kernel approach runs Linux as a thread of a real-time operating system. The company's engineers claim that the dual-kernel approach combines the best features of Linux with hard real-time performance. "Linux provides some very sophisticated features and our design enables us to get hard real-time without sacrificing performance," notes Victor Yodaiken, CEO of FSMLabs. Yodaiken adds that RTLinuxPro offers "low-microsecond interrupt latency and scheduling jitter" along with full access to a 2.6 Linux kernel for non-real-time programs. Pratt & Whitney employed RTLinuxPro in afterburner tests of the F135 engine. For more information, go tohttp://rbi.ims.ca/4397-532.