The ARM® Toolchain is a collection of tools/libraries used to create applications for ARM microcontrollers. This collection includes compiler, assembler, linker and Standard C and math libraries.
Most of these tools are based on efforts from GNU (www.gnu.org), and some are developed by Microchip. For more information please refer to the release notes.
The Atmel AVR GNU Toolchain is also available as part of Atmel Studio. Only those users who wish to run the Atmel AVR GNU Toolchain as standalone tools from the command line need to download and install this package. There are two sets of downloads, one for Windows® and one for Linux® operating systems.