I was more referring to the historical perspective of how C became popular, many have fallen by the wayside. Though there are certainly current alternatives to C besides those on TIOBE.
Also there are real-time extensions to current GC'd languages like Java.
(Though standard C isn't very predictable timing-wise either, or suited to real-time work)
And, with the exception of Ada and Pascal, most of those language have been dead for at least 20 years--for various good reasons.
And, please do remember that Apple switched away from Pascal when writing its operating systems in spite of an enormous code base. That's pretty damning--apparently C's "undefined behavior" didn't seem to matter.
So, we're back to: the only alternative to C is Ada.
> Though there are certainly current alternatives to C besides those on TIOBE.
Let me make it easy. Give me a list of languages that have been used to build an operating system in a product in the last 20 years. It doesn't have to be Linux, even a small RTOS counts.
I'll start the list:
C family--C, C++, ObjC/Swift
Forth(?)--probably counts as it runs on pretty bare metal
Ada--not sure anybody has used it to build an OS, but I don't debate that they could
Rust--has a feature set of articles about this
Pascal--the original Lisa and Macintosh OS (probably stretching that 20 year limit a bit).
I am happy with your list of languages to write an OS in, maybe add D and Oberon. I'd point out that you can also use managed languages, see MS Singularity, or the various Lisp and Smalltalk operating systems, or the UCSD P-system, etc - there is a list at https://en.m.wikipedia.org/wiki/Language-based_system .
Counting new commercial operating systems is not a useful benchmark as they are very rare, and we already agreed that the alternatives are not popular.
I'd love to have a nice language alternative to C.