> The JVM is written in C, Python/Perl/Ruby/v8 etc. are written in C or C++. This is disingenuous - that's exactly like saying that ZetaC on the Lisp Machine w

> The JVM is written in C, Python/Perl/Ruby/v8 etc. are written in C or C++. This is disingenuous - that's exactly like saying that ZetaC on the Lisp Machine was written in Lisp and not in microcode, so Symbolics is a polyglot machine. The reason that a lot of dynamic programming language runtimes (like the JVM, SBCL, etc) use C is exactly because the only alternative on Unix is to hand-code system calls in assembly. The code generators are almost always self-hosting in these languages. > It's certainly nicer to write languages in C than in assembly. C is a bad language to target compilers and transpilers to if you need non-standard control flow because it forces you into a stack discipline. Doing things like continuations or restartable exceptions requires Rube Goldberg machine-level workarounds. > Treating everything as byte streams is another big reason that it is polyglot. This has obvious downsides, but if you stored everything as s-expressions, or C structs, then it would privilege one language over another. Traditional Unix utilities don't use architecture-dependent binary formats, and this is one of the main reasons why. Even the idea of byte streams is a C-ism. Bytes on the PDP-10 would "naturally" come out to 6 bits (out of a 36-bit word) - the instruction set was based around flexible bit fields. > But honestly, the only other solution would have been to define an RPC-like architecture-independent interface -- what operating systems do that? I don't know of any. That sounds like a microkernel. But I think the real takeaway here is that any operating system is going to come with baggage for language implementors, and it is important to recognize and make explicit what these assumptions are and why they were made (like for example I don't think many people ever think about the non-8-bit-bytes thing, but it is important if you want to provide a nice interface for bit-banging: http://clhs.lisp.se/Body/f_ldb.htm#ldb http://clhs.lisp.se/Body/f_ldb.htm#ldb)