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It's sad, but worse is better is so pervasive, that even many of you very smart people have difficulty conceiving of what the problem is, much less what would be a better way, not because it's particularly hard, but because of technology culture. It seems trivial. Just return an error, right? I've had to deal with the problems of EINTR for so long. SA_RESTART seems nice, but you can't rely on it, and it only begins to scratch the surface of what would actually be "better". How about you can call anything in a signal handler? How about any code, user or kernel, be safely re-entered? Of course you can't magically solve every concurrency and resource contention problem, but having functional style, and things like unwind-protect, language support for safety, etc. goes a surprisingly long way. How about you can have arbitrarily many signal handlers for any condition and have arbitrarily many places to continue on the stack, which can receive arbitrary data? How about I can call a system call from inside a signal handler, from inside the debugger, from inside a signal handler, inside a system call, and pop up a UI to ask the user what they want? How about every piece of code can be moved around and called from anywhere? How about you can pass around an objects that can resume a function or a system call in the middle? How about the thing reading trashy network packets doesn't have absolute power, while my user process doesn't have permission to close the lid or play audio? Not just Lisp code, but a large fraction of modern languages that have things like GC and bignums, have to make sure it's safe to do anything, even in the middle of adding a number. So why can't we have these things that have been well known for over 40 years? But I'm sure you're familiar with the relatively small set of crews that designed most the stuff we use. vmlinux, kernel32.dll, and even shabby xnu, might be cute, like the jerq is a cute joke on the perq, if we didn't have to actually rely on them for real stuff. Unfortunately, it's not hard to see that the worse-is-better culture is a result of larger human culture, which is pushed around by the same typical things. But the good thing is that culture being intangible, it only takes the mostly mental acts of skepticism, education, and personal communication, to change it. |