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Welcome to the Fiwix project
A UNIX-like kernel for the i386 architecture
Fiwix kernel


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 with only 35,000 lines of code, runs on the 32-bit x86 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 the Assembler the small needed parts. It follows the System V Application Binary Interface (or ABI) and is also Linux 2.0 System Call ABI mostly compatible.

Fiwix uses the Newlib v2.2.0 as its system C Library, and the Minix v2 as its primary file system.

The kernel, while completely functional and self-hosting capable, is in its early stage. That is, don't expect some features you would find in current (modern) kernels. So, no PCI devices, no USB support and no networking, to name the most impacting missing features.

Go to the Downloads page to know how to install the complete 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.