I have used and taught Ada, for what that's worth. I also looked at Ada for writing OS kernel code, but the quality of the compilers forced me back to the C family.
Question for the proponents of Ada: how many operating system kernels do you know of which are written in Ada? Now answer the same question for C. For extra marks, explain why the discrepancy, paying particular attention to the strengths and weaknesses of each language in this particular usage. -- Christopher Vance
