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operating-systemkernelosdev

For kernel/OS is C still it?

I like operating systems and would eventually like to become a OS developer mostly working on kernels. In the future will C still be the language of choice and what else should I be trying to learn?

Solution

  • I think it's safe to say that low-level parts of operating systems (e.g. the kernel) will continue to be written in C because of its speed. Like mentioned elsewhere, you will need to know assembler for certain parts of the kernel (something needs to load the kernel into memory). But you can work on the kernel with little or no assembly knowledge. A good example would be if you're implementing a file system.

    Don't worry about what language the operating system is implemented in. What's important is how an operating systems are used, and what can be done to improve them. A good example is when Unix first came out. The file system had the inodes at the front of the disk, and data in the remaining space. This didn't perform very well as you were seeking to different parts of the disk for all files. Then the Berkeley Fast File System was created to make a disk aware file system. This means having inodes near their corresponding data. I'm leaving out a lot of details, but I hope this illustrates that it's more important to think about how an operating system can be improved rather than what language it will be programmed in.

    Some recent trends in operating systems are virtualization and distributed computing (see Google's paper on MapReduce). File systems, security, scheduling (especially with multi-core processors), etc are continually areas of interest even though these problems are not new.

    Here are some resources if you want to learn more about kernel development:

    • Linux Kernel Newbies - Resource for those who want to get started on modifying the Linux kernel.
    • xv6 source - x86 port of Unix version 6. Used by MIT to teach an operating systems class. Simple, and easy to extend (more info).
    • Linux Kernel Map - Call chain of system calls in Linux. Useful in visualizing what a system call does.

    Bottom line: Start getting familiar with the kernel and read papers on what researchers are writing about (USENIX is useful for this). This knowledge is much more valuable than learning a new language, as most concepts from one language can easily be transferred to another if there does happen to be a shift in what operating systems are written. Hope this helps!