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omazurov

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omazurov
·3 lata temu·discuss
No mature, sensible code allows for 10x performance improvement (let alone...). Every time I see a statement like this I take it as a confession.
omazurov
·3 lata temu·discuss
My personal recommendation for a Tarkovsky's first is his diploma film The Steamroller and the Violin (1960, 46 min, co-written with Andrei Konchalovsky). It was surprisingly watchable [for me] and I wish I had watched it first myself before I was exposed to the Mirror when I was 16.

[0] https://en.wikipedia.org/wiki/The_Steamroller_and_the_Violin
omazurov
·3 lata temu·discuss
You get JFR's precision but inherit its blind spots as described in [1]:

> demo1: ... JFR will not report anything useful at all, since it cannot traverse stack traces when JVM is running System.arraycopy()

I'd rather run jstack in a loop than lose System.arraycopy() (or, in fact, any native code be it JVM's or JNI).

[1] https://github.com/apangin/java-profiling-presentation
omazurov
·3 lata temu·discuss
>Profilers are not rocket science...

They are not. There are orders of magnitude more rocket scientists than good profiler writers. And no, bottle rockets with flight recorders do not count.
omazurov
·3 lata temu·discuss
>...retrocausal models also open avenues of exploring a “time-symmetric” view of our universe, in which the laws of physics are the same regardless of whether time runs forward or backward.

... or sideways!

If you want a visual model that may help to build some intuition about that, I have one at [1]. Retrocausality is not explicitly spelled out in that model but "it's uh... uh... it's down there somewhere".

[1] https://github.com/OlegMazurov/Janus
omazurov
·4 lata temu·discuss
Necessity is the mother of invention? (Голь на выдумки хитра? :( )
omazurov
·4 lata temu·discuss
I can only repeat my initial statement:

> Multi-dimensional RS codes are an easy way to get to an absurdly huge size for real.

"Multi-dimensional" may mean 3,4,..,10 dimensions. "Absurdly huge" means a petabyte and beyond. "For real" means practical recovery of swaths of lost or damaged data. "Fountain LDPC codes" are essentially one-dimensional. Extending them to the ability of recovering an annihilated data center would make them impractical. Making them multi-dimensional would make them inferior to RS (which is still MDS in every single dimension).
omazurov
·4 lata temu·discuss
I'm not talking about CD-ROMs or immediate availability in any form. How would you encode a petabyte (for a starter) with LDPC/Turbo? Not available right away but accumulated over months with no predefined upper limit? Computational cost remains an important factor but other requirements take over.
omazurov
·4 lata temu·discuss
> Larger and larger block sizes are important. LDPC probably is the more practical methodology today, though I admit that I'm ignorant about them. Still cool to see someone try to push Reed Solomon to such an absurdly huge size though.

Multi-dimensional RS codes are an easy way to get to an absurdly huge size for real (granted they stop being MDS). Long term archiving is an obvious application. One-way communication, like in deep space, is another. Though, speed requirements are less demanding there. That one tried to push the envelope for a one-dimensional RS code to those limits is a curiosity. Some techniques may be useful in other practical approaches. It's a pity the code representation had to depart from GF(2^n).