GNU’s Not Unix (GNU)
GNU is an extensive collection of free software, which can be used as an operating system or can be used in parts with other operating systems.
Components
The GNU Arm Embedded toolchain contains integrated and validated packages featuring the GCC compiler, libraries, and other tools necessary for bare-metal software development. These toolchains target devices that are based on 32-bit Arm Cortex-A, Cortex-R and Cortex-M processors.