Think about usage patterns, maybe I am wrong but no actual VM execution model adapts program execution at running/history characteristics.
Yep, I think you're wrong. Look up "value profiling" for instance. It means finding values that are effectively constant on a particular run of a program, and recompiling that program on the assumption that the value will indeed be constant.
For instance, imagine the UNIX "wc" (word count) program were written in Java. An advanced JIT compiler could tell, for instance, that you have specified the "-l" option, and therefore you only need to count lines. The portions of the program that count letters and words would get removed as dead code, which probably speeds up the inner loop a great deal.
Moden JIT compilers produce self-profiling code, and then re-compile with the profiling information to produce a specialized version of the code that will run faster under the current conditions.
If that's not the "introspection" you're talking about, then perhaps I have misunderstood. Can you give an example?
Why not spend our ever increasing computing power to create 'introspective' programs?
We do. That's what modern JVMs do.
Re:What's the point in Java bytecode anyway?
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JIT vs AOT Compilation
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· Score: 5, Informative
It is parse trees. It's stack-based, which is pretty much just a post-order traversal of expression trees. Think of bytecode as a file format for describing expression trees.
If you can show me a commercial JIT compiler that doesn't already do this, I'll eat my hat. What you call "dynamic compilation" is so routine and mundane that when people talk about "JIT compilers" these days, that is exactly what they are talking about. Nobody blindly compiles on the first invocation of a method any more.
What you have mentioned is not the crux of the problem. I can't say much more because I do confidential work on IBM's JIT compiler.
Were you planning to run your tractor on biodeisel too?
Yes.
It may turn out that the fuel used to plow a certain area of a field needs the same area's worth of produce to make the biodeisel that powers the tractor.
Perhaps that they are counting the crude oil removed from the ground. Thus, for every 0.81 gallons of gas we get, it costs us 0.19 gallons and it costs the ground 0.81 gallons.
The only thing I can imagine is that the input energy is not all in the form of gasoline. Otherwise, it seems absurd to pay 1 gallon of gas to get 0.81 gallons.
In a kernel, all the code needs to be transparent, and you definitely don't want to hide implementation and the usual abstractions.
This argument suffers from a common misconception: that "information hiding" means hiding information from developers. It doesn't. It means hiding information in one software module from another.
Abstractions are not inherently opposed to what you're referring to as "transparency". Good abstractions don't harm transparency, and actually make code clearer by clearly defining the interactions between modules.
Uh, that's total bullshit. Code can only say what it's doing. It can't describe why. It can't explain implementation limitations (eg. "this is an O(n^2) algorithm, but I have chosen it for simplicity because I don't expect n to be larger than 25"). It can't contain TODOs (Fred Brooks' "purple wires").
If you think you can get away with no comments in lisp or prolog, then you haven't written very large lisp or prolog programs.
My guess is that mere xenophobia would be eclipsed by the much more powerful strategy of joining the ongoing discussion about which agents can and can't be trusted.
The idea isn't to necessarily make the trip much faster - though that will happen over time with conventional air travel - but to improve the experience enough that passages won't mind a 20 hour flight so much.
Yes, that's why we all travel around in luxurious decadence in our fabulous 21st century horse-drawn carriages.
Besides, if flying in space becomes so commonplace that I can get to Australia - I might as well just go to the moon!
To make a statement like this requires a remarkable depth and breadth of ignorance of the laws of orbital mechanics. "If flying through the air becomes so commonplace that I can jump from my kitchen to my living room, then I might as well fly to work!"
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For instance, imagine the UNIX "wc" (word count) program were written in Java. An advanced JIT compiler could tell, for instance, that you have specified the "-l" option, and therefore you only need to count lines. The portions of the program that count letters and words would get removed as dead code, which probably speeds up the inner loop a great deal.
Moden JIT compilers produce self-profiling code, and then re-compile with the profiling information to produce a specialized version of the code that will run faster under the current conditions.
If that's not the "introspection" you're talking about, then perhaps I have misunderstood. Can you give an example?
It is parse trees. It's stack-based, which is pretty much just a post-order traversal of expression trees. Think of bytecode as a file format for describing expression trees.
What you have mentioned is not the crux of the problem. I can't say much more because I do confidential work on IBM's JIT compiler.
They want their idea back.
Perhaps that they are counting the crude oil removed from the ground. Thus, for every 0.81 gallons of gas we get, it costs us 0.19 gallons and it costs the ground 0.81 gallons.
The only thing I can imagine is that the input energy is not all in the form of gasoline. Otherwise, it seems absurd to pay 1 gallon of gas to get 0.81 gallons.
Yes, the video is total crap. This, on the other hand, is cool.
Abstractions are not inherently opposed to what you're referring to as "transparency". Good abstractions don't harm transparency, and actually make code clearer by clearly defining the interactions between modules.
If you think you can get away with no comments in lisp or prolog, then you haven't written very large lisp or prolog programs.
And mod this down.
...and not a single comment.
It's a lunar eclipse. Totality will be on the moon.
When will people learn that 300 million people can have more than one focus.
I just have to say that's the funniest "from the dept." line I have ever seen here. (Not that that's saying much.)
Parent is classic flamebait, and it's not even very well disguised.
Aryabhata was launched by the Russians. There's a big difference between building a satellite and having a space programme.
What you are missing is that nobody ever claimed TfT would never lose.
I bet you a beer that there will be no private orbital flights a year from now.
No, satellites require orbit. These flights are sub-orbital. Think pogo-stick versus jet plane.
It's for "Libre".