3 ms·

I spent a lot of time trying to understand what you were saying, and because it was unclear to me I asked very specific questions, none of which you answered:

I spent a lot of time trying to understand what you were saying, and because it was unclear to me I asked very specific questions, none of which you answered: - what will people write language implementations in, if not C? - why don't you consider my JIT an innovation worth supporting? - if C is a barrier to innovation, why is the JavaScript landscape so thriving? My point about Brainfuck (that's a language by the way, not a slur, in case that wasn't clear) is that Turing-completeness says almost nothing about the systems-level capabilities of the language. Turning completeness means that a language can calculate Pi: it doesn't mean that it can open a file or send data over a network, and it says nothing about efficiency. So when you argue that Turing-completeness is what makes it possible to run lots of different kinds of VMs on the same machine, it's hard to take such an argument seriously.

jerf 16y ago
"So when you argue that Turing-completeness is what makes it possible to run lots of different kinds of VMs on the same machine, it's hard to take such an argument seriously." Turing completeness is why you can run a JVM on top of a C environment. It means that any computation that C could do, the JVM could do. It means that I can run a JVM on top of any Turing Complete environment. The JVM could be ported to a modern day Lisp machine. The JVM could run on a Russian ternary machine. C does not get "credit" for enabling the existence of the JVM, because the JVM could run on any Turing complete substrate. You have the causality backwards. "- what will people write language implementations in, if not C?" The new systems languages will be written in themselves! What do you think C is written in? "Bootstrapping." "- if C is a barrier to innovation, why is the JavaScript landscape so thriving?" Wrong question for what I'm talking about. Javascript has no innovation of interest to systems level programming, it's just a thin layer over C. I'm talking more like something like Go, which is hampered by the fact that it can't really use C libraries properly because Go can't grab and schedule C routines properly. Or how E [1] is really hampered by the fact that it basically can't work properly in a C environment, its whole schtick really only works if it's down to the OS level. The entire point is that I want to replace the foundation, so it can do things that C basically can't. Like, write a secure operating system, which C is incapable of, despite immense amounts of effort. Basically, why is UNIX still the preeminent OS? Yes, it was good, I know that, there's a reason why it's the only survivor of its time period, but where's the capabilities-based system? Where's the thing we can't even think of because we're too stuck on C? Why is one of the preeminent kernels of the day, the Linux kernel, still adding an average of two security vulnerabilities a week, the same ones, over and over? Why are buffer overflows still coming out in 2011? Why do I still get segmentation faults in 2011? Why are we building the very foundations of our system on a language that all but mandates such failures, when we know how to not do that? C. As for any response you might have as to why C is still worth it, my reply in advance is that every one of those things is room for "innovation", much of which has already been done. [1]: http://www.erights.org/ http://www.erights.org/
- haberman 16y ago
  > Turing completeness is why you can run a JVM on top of a C environment. It means that any computation that C could do, the JVM could do. I'm genuinely confused: I thought this was the argument you called a strawman when I argued against it before. I've already rebutted this argument twice: Brainfuck (http://en.wikipedia.org/wiki/Brainfuck http://en.wikipedia.org/wiki/Brainfuck) is a Turing-complete programming language, and yet you categorically could not implement the Java class libraries on top of it. For example, the java.io.FileReader class could not be implemented on top of it, because Brainfuck does not have any API for opening a file. Even in cases where you can implement one language on top of another, it may not be efficient to do so. For example, Adobe Alchemy runs C/C++ code on top of Flash/ActionScript at a 2-10x slowdown compared with running the C/C++ directly on the hardware. Implementing a JVM on top of Java appears to be 4-9x slower than implementing it in C/C++ [0] (and that's only comparing two interpreters: the difference is far greater when the C/C++ implementation generates machine code directly). C gets credit for efficiently supporting a whole host of different VMs with divergent GC schemes and synchronization primitives. That is what makes C special, and why it continues to dominate in system space. [0] http://portal.acm.org/citation.cfm?id=1294345 http://portal.acm.org/citation.cfm?id=1294345

jerf 16y ago

"So when you argue that Turing-completeness is what makes it possible to run lots of different kinds of VMs on the same machine, it's hard to take such an argument seriously." Turing completeness is why you can run a JVM on top of a C environment. It means that any computation that C could do, the JVM could do. It means that I can run a JVM on top of any Turing Complete environment. The JVM could be ported to a modern day Lisp machine. The JVM could run on a Russian ternary machine. C does not get "credit" for enabling the existence of the JVM, because the JVM could run on any Turing complete substrate. You have the causality backwards. "- what will people write language implementations in, if not C?" The new systems languages will be written in themselves! What do you think C is written in? "Bootstrapping." "- if C is a barrier to innovation, why is the JavaScript landscape so thriving?" Wrong question for what I'm talking about. Javascript has no innovation of interest to systems level programming, it's just a thin layer over C. I'm talking more like something like Go, which is hampered by the fact that it can't really use C libraries properly because Go can't grab and schedule C routines properly. Or how E [1] is really hampered by the fact that it basically can't work properly in a C environment, its whole schtick really only works if it's down to the OS level. The entire point is that I want to replace the foundation, so it can do things that C basically can't. Like, write a secure operating system, which C is incapable of, despite immense amounts of effort. Basically, why is UNIX still the preeminent OS? Yes, it was good, I know that, there's a reason why it's the only survivor of its time period, but where's the capabilities-based system? Where's the thing we can't even think of because we're too stuck on C? Why is one of the preeminent kernels of the day, the Linux kernel, still adding an average of two security vulnerabilities a week, the same ones, over and over? Why are buffer overflows still coming out in 2011? Why do I still get segmentation faults in 2011? Why are we building the very foundations of our system on a language that all but mandates such failures, when we know how to not do that? C. As for any response you might have as to why C is still worth it, my reply in advance is that every one of those things is room for "innovation", much of which has already been done. [1]: http://www.erights.org/ http://www.erights.org/

haberman 16y ago
> Turing completeness is why you can run a JVM on top of a C environment. It means that any computation that C could do, the JVM could do. I'm genuinely confused: I thought this was the argument you called a strawman when I argued against it before. I've already rebutted this argument twice: Brainfuck (http://en.wikipedia.org/wiki/Brainfuck http://en.wikipedia.org/wiki/Brainfuck) is a Turing-complete programming language, and yet you categorically could not implement the Java class libraries on top of it. For example, the java.io.FileReader class could not be implemented on top of it, because Brainfuck does not have any API for opening a file. Even in cases where you can implement one language on top of another, it may not be efficient to do so. For example, Adobe Alchemy runs C/C++ code on top of Flash/ActionScript at a 2-10x slowdown compared with running the C/C++ directly on the hardware. Implementing a JVM on top of Java appears to be 4-9x slower than implementing it in C/C++ [0] (and that's only comparing two interpreters: the difference is far greater when the C/C++ implementation generates machine code directly). C gets credit for efficiently supporting a whole host of different VMs with divergent GC schemes and synchronization primitives. That is what makes C special, and why it continues to dominate in system space. [0] http://portal.acm.org/citation.cfm?id=1294345 http://portal.acm.org/citation.cfm?id=1294345