FemtoLinux is a new Linux flavor optimized for real-time embedded systems. With FemtoLinux, critical Linux applications run in kernel mode. This results a low system call and interrupt-to-application latency and overhead. FemtoLinux also simplifies RTOS-to-Linux porting significantly — RTOS applications can be ported to embedded Linux without drastic changes to the software architecture. FemtoLinux is available now for the ARM architecture. MIPS and PowerPC ports are in the works.
FemtoLinux kernel mode processes are similar to VxWorks 5.x tasks. They run in the same address space as the kernel and can access kernel and hardware resources directly, reducing system call overhead to a simple function call. This approach also enables the creation zero-copy applications, which is important for services that transfer large bulks of data to/from kernel, such as many networking applications.
FemtoLinux tasks offer performance and latency improvements compared to regular Linux applications, especially for system call intensive applications. FemtoLinux can also help in porting legacy RTOS applications to Linux, allowing to keep the same monolithic driver and application architecture on both operating systems.
FemtoLinux extends embedded Linux to new areas such as cellular baseband processors, which are currently dominated by operating systems such as ThreadX and Nucleus.
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