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How to Make a Computer Operating System

Operating systems allow people to interact with computer hardware; they're made out of hundreds of thousands of lines of code. They are usually made with C#, C, C++, and assembly. Operating systems allow you to navigate through a computer while creating storage and executing commands. It isn't easy to make one and requires a lot of knowledge.


  1. 1
    Learn programming before you begin. Assembly language is essential; another supplementary high level language such as C is strongly recommended.
  2. 2
    Decide what media you want to load your OS on. It can be a CD drive, DVD drive, flash drive, a hard disk, a floppy disk, or another PC.
  3. 3
    Decide on your core idea of an OS. In Windows, for instance, an easy-to-use GUI and plenty of security is the core idea.
  4. 4
    Target what processor platform your operating system will support. IA-32, ARM, and x86_64 are the most common for personal computers so they're your best bet.
  5. 5
    Decide if you would rather do it all yourself from the ground up, or if there is an existing kernel you would like to build on top of. Linux from scratch is a project for those that would like to build their own Linux distro, for example.
  6. 6
    Decide if you're going to use your own boot-loader or a pre-created one such as Grand Unified Bootloader (GRUB). Since coding your own bootloader will require extensive knowledge of the hardware and the BIOS, it may push back the schedule for programming of the actual kernel.
  7. 7
    Decide what programming language to use. While it is possible to create an operating system in a language such as Pascal or BASIC, you will be better off using C or Assembly. Assembly is absolutely necessary, as some vital parts of an operating system require it. C++, on the other hand, contains keywords that need another fully-built OS to run.
    • In order to compile an operating system from C or C++ code, you will, of course, be using one compiler or another. You should, therefore, read the user guide/manuals/documentation for your chosen C/C++ compiler, whether it comes packaged with the software or is available on the distributor's website. You will need to know many intricate things about your compiler and, for C++ development, you should know about the compiler's mangling scheme and its ABI. You are expected to understand the various executable formats (ELF, PE, COFF, plain binary, etc.), and understand that the Windows proprietary format, PE (.exe), has been copyrighted.
  8. 8
    Decide on your application programming interface (API). One good API to choose is POSIX, since it is well documented. All Unix systems have at least partial support for POSIX, so it would be trivial to port Unix programs to your OS.
  9. 9
    Decide on your design. There are monolithic kernels and micro kernels. Monolithic kernels implement all the services in the kernel, while microkernels have a small kernel combined with user daemons implementing services. In general, monolithic kernels are faster, but microkernels have better fault isolation and reliability.
  10. 10
    Consider developing and working in a team. That way, less time is required to solve more problems, which may produce a better OS more quickly.
  11. 11
    Do not wipe your hard drive completely. Remember, wiping your drive will irreversibly clear out all your data! Use GRUB or another boot manager to dual-boot your system with another OS until yours is fully functional.
  12. 12
    Start small. Begin with small things such as displaying text and interrupts before moving on to things such as memory management and multitasking. You can also try making a simple 16-bit Operating System, instead of taking a big leap.
  13. 13
    Keep a backup of the last working source. This provides a measure of protection in case something goes terribly wrong with the current version of your OS or your development. If your computer crashes and is unable to boot, it is an excellent idea to have a second copy to work with so you can troubleshoot.
    • (If you need keep a backup, make sure there are 2 - 3 disk partition. 1 OS as an OS will develop another one, and 1 backup of old version(older, not oldest), and 1 partition for current version)
  14. 14
    Consider testing your new operating system with a virtual machine. Rather than rebooting your computer each time you make changes or having to transfer the files from your development computer to your test machine, you can use a virtual machine application to run your OS while your current OS is still running. VM applications include VMWare (which also has a freely available server product), the open-source alternative, Bochs, Microsoft Virtual PC (not compatible with Linux), and Oracle VirtualBox.
  15. 15
    Release a "release candidate." This will allow users to tell you about potential problems with your operating system, or the rating about your operating system.
  16. 16
    An operating system can be user friendly too, so make sure to add user friendly features, making these an integral part of your design.