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Welcome to the Fiwix project
Your small UNIX-like kernel

What is FiwixOS?

FiwixOS 3.3 is a Fiwix distribution, an operating system made from a software collection that is based upon the Fiwix kernel. It basically comprises the Fiwix kernel, GNU Toolchain, libraries and additional software. All the included software is free and open-source software made available both as compiled binaries and in source code form.

FiwixOS 3.3 uses Newlib as its standard C library, and the Ext2 as its primary file system.

Fiwix is an operating system kernel written from scratch, based on the UNIX architecture and fully focused on being POSIX compatible. It is designed and developed mainly as a hobby OS and, since it serves also for educational purposes, the kernel code is kept as simple as possible for the benefit of students and OS enthusiasts. It is small in size (less than 50K lines of code), runs on the i386 hardware platform and is compatible with a good base of existing GNU applications.

It is based on the monolithic kernel design and it is written entirely in C language, leaving only for Assembly the small needed parts. It follows the System V Application Binary Interface (ABI) and it also aims for Linux 2.0 system call compatibility, while keeping the essence of UNIX as much as possible.

Go to the Downloads page to know how to install this operating system and start tinkering with the kernel source code.

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Just install the software and test it. If you encounter any error, please notify it. If you think there are some parts that could be improved, please share your ideas.

You can contribute in any of the following ways:

  • Submitting patches.
  • Adding new features.
  • Improving project documentation.
  • Sending suggestions and new ideas.
  • Porting packages.


Fiwix is an open source initiative and is released under the MIT License.