Linux kernel development started in 1991, and it is also written in C. Although Windows source code is not publicly available, it’s been stated that its kernel is mostly written in C, with some parts in assembly. It became one of the most popular databases in the world. Oracle database development started in 1977, and its code was rewritten from assembly to C in 1983.
The C language was actually created to move the UNIX kernel code from assembly to a higher level language, which would do the same tasks with fewer lines of code. The UNIX operating system’s development started in 1969, and its code was rewritten in C in 1972. Many of the C projects that exist today were started decades ago.
