Comment by haberman | Hacker News Reader

Comment by haberman | Hacker News Reader

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> As for the GC, I can give the Squawk example which has a GC done in Java, targets embedded systems, with C/C++ only being used for hardware integration part.

I didn't say it was impossible, just slow, and it is:

"My third reservation is Squawk's performance, which is roughly that of the J2ME-derived Java KVM introduced a few years ago, an interpreted JVM that is written in C. From everything I have learned about it, the developers are assuming that most applications for the SPOT platform will include processors of sufficient power and that large amounts of memory will be available for garbage collection, pointer safety, exception handling and a mature thread library for thread sleep, yield and synchronization. That is not true in many cases, and if SPOT is limited to only sensor applications that are not performance-constrained, the platform is interesting but not all that important in the long run."

http://www.embedded.com/electronics-blogs/cole-bin/4025677/S...

It just needs to be fast enough to fulfill the required tasks, not a blazing thunder.

This is how C replaced Assembly in many use cases, C++ replaced C in many use cases, ...

A large part of the asm => C and C => C++ moves is that C and C++ very ,very strictly follow the principle that you pay only for what you use, and that pretty much all C and C++ environments makes inline assembler quite easy to do.

In other words: You can write C++ that is no slower than C, and you can write C that is only rarely slower than ASM, and in both cases, in the few situations where the performance difference is large enough to be noticeable and matter, you can still easily write asm.

This is also why C and C++ keeps being used in the face of so many higher level languages.

And I say this as someone who spends most of his time writing Ruby, and who haven't even bothered upgrading to MRI 2.x despite the performance improvements available.

In other words: I agree with your first line. But moving to C/C++ is a totally different tradeoff than moving to most higher level languages, most of which at the very least makes the performance characteristics much harder to predict.

There are higher level languages like Modula-2 and Ada that offer type safety and once upon a time, had compilers with comparable performance to C, back when C was UNIX only.

Of course, 30 years of industry investment into C compiler backends changed this relation.

Unfortunately, thanks to Sun and Microsoft VM über alles attitude in the past decade, young developers tend to equate higher level languages with VMs and think C and C++ are the only languages with proper native code compilers.

> you pay only for what you use

In assembly and C, but not C++, at least if you use exceptions:

http://yosefk.com/c++fqa/exceptions.html#fqa-17.1

Of course you can pare down C++ further and further, but then you have C with slightly different type-checking semantics and you might as well move to a language where 'new' isn't a reserved word.

> you pay only for what you use

This is only half of the equation. The other half is what are the costs of the things you do use. E.g. costs of exceptions, virtual calls, dynamic linking, dynamic memory allocation, concurrency, etc. Java is like an all-inclusive offer - you get more at a higher cost, probably with something you don't need, but often it is cheaper than to buy every service one by one.

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