The Programming Languages Behind Linux: C, C and Assembly
Linux, the popular open-source operating system, is not simply a monolithic program. It is a multi-layered entity, with various components written in different programming languages. The core of Linux, the kernel, is primarily written in C, complemented by some assembly language. Let's delve into the details of how Linux is constructed.
Is Linux Written in C or C ?
The Linux kernel is indeed written in C, using certain non-standard extensions available in the GNU Compiler Collection (GCC). While C is the primary language, it is not strictly ISO C. Additionally, there is a small portion of the kernel written in assembly language for hardware-specific optimizations and performance gains.
C Extensions in GCC
Regrettably, sometimes the standard C language adopts features from GCC, but not all the time. Linus Torvalds, the creator of Linux, is known to have a keen eye for detail and often expresses distaste for C, though whether that could be classified as true hate is debated. Despite his feelings, the majority of the kernel is still written in C, taking advantage of GCC's extensions.
Why Does the Linux Kernel Use C?
Initially, the development of the Linux kernel occurred before the C language had an ISO standard. This, combined with Torvalds' personal preferences, led to the decision to use C. While the core design is based on C, the language offers a balance between performance, ease of use, and maintainability.
Other Programming Languages in Linux
Beyond the core kernel, the Linux ecosystem includes various tools and utilities. These are often written in C, as is the case with many GNU project components. However, you may encounter programs written in other languages such as Bash, Python, or Perl, depending on the specific distribution and utilities installed.
Understanding the Linux Kernel
To truly understand how Linux is structured, you can download and examine its source code. This is accessible via open-source repositories, and most distributions offer the option to install developer versions of libraries alongside the standard versions. Provided below is a video that offers a detailed explanation of the kernel's composition:
Furthermore, there are numerous resources available to help you learn, including online tutorials, books, and academic courses. Many computer science programs have mandatory operating systems courses that cover the fundamentals of how an OS works and how to write efficient software that interacts directly with it.
Real-World Application
For instance, several years ago, a student in my class wanted to optimize the Linux kernel for a multiplayer online game. This involved a deep dive into how operating system schedulers work and resulted in performance improvements. This project not only provided practical experience but also reinforced the importance of kernel-level programming for specialized applications.
In conclusion, Linux is a diverse and complex system, utilizing C as its primary language for the kernel, with assembly for hardware-specific optimizations. The entire ecosystem is built on the foundation of open-source code, inviting developers and enthusiasts alike to explore and contribute to its evolution.