Apex

Apex is a real-time operating system (RTOS) designed for use in small to medium scale embedded systems. It aims to be a bridge between traditional RTOSes for small microcontrollers and Linux for larger embedded systems. Apex provides a Linux-compatible environment, making it easier for developers familiar with Linux. The RTOS is currently under heavy development and is not considered stable.

Features

• Implements a subset of the Linux syscall interface.
• Uses the musl C library.
• Monolithic architecture (as opposed to microkernel).
• Open source & royalty-free.
• Secure & reliable.
• Small, efficient, and easy to understand.
• Binary compatibility with Linux (using musl libc).
• Development can focus on the kernel as userspace tools & libraries are provided by external projects.

Components

• Boot Loader: Responsible for initializing the system and loading the kernel.
• CPU: Contains CPU-specific configurations and sources.
• Libc: C library for the bootloader and kernel.
• Libc++: C++ library for the bootloader and kernel.
• Machine: Contains machine/board support files.
• MK: Build system.
• Sys: Apex kernel which includes:
  • Architecture support.
  • Device drivers.
  • File systems.
  • Kernel core.
  • Memory management.
  • Synchronization primitives.