kurlberg

On a whim I gave w3m (or w3m-el to be precise) a try on this page, and it worked - I found a new adblocker-blocker-blocker, and I'm quite happy I did got to read this gem of a summary at the end of the article:

>In short, the mathematics of self-organizing lists suggests >something radical: the big pile of papers on your desk, far >from being a guilt-inducing fester of chaos, is actually one >of the most well-designed and efficient structures >available. What might appear to others to be an unorganized >mess is, in fact, a self-organizing mess. Tossing things >back on the top of the pile is the very best you can do, shy >of knowing the future. You don’t need to organize that >unsorted pile of paper. > >You already have.

A case of life imitating AI koans:

Uncarved block

In the days when Sussman was a novice, Minsky once came to him as he sat hacking at the PDP-6. "What are you doing?", asked Minsky. "I am training a randomly wired neural net to play Tic-tac-toe", Sussman replied. "Why is the net wired randomly?", asked Minsky. "I do not want it to have any preconceptions of how to play", Sussman said. Minsky then shut his eyes. "Why do you close your eyes?" Sussman asked his teacher. "So that the room will be empty." At that moment, Sussman was enlightened.

(It seems based on a true story https://en.wikipedia.org/wiki/Hacker_koan )

The main point is not about generating skewed distributions, it's about "universality" - the same distribution starts popping up in seemingly unrelated settings. E.g., (large) eigenvalues of random matrices is connected to the length of the longest increasing subsequence of permutations. In a sense it's the discovery of a new kind of central limit theorem.

If you know emacs I recommend taking a look at org-mode. It's an emacs mode that let's you write in "markdown" (but including tex-syntax for math) and then lets you export to html or pdf (via tex/latex.)

Scary scenarios regarding "faulty ram destroys volume" can be found in various places, e.g.,

https://pthree.org/2013/12/10/zfs-administration-appendix-c-...

However, for a refutation of this scenario see XorNot's comment (and perhaps the surrounding discussion) at

https://news.ycombinator.com/item?id=8294434

This is indeed where I read it. When googling to find it again I found a similar story at:

https://pthree.org/2013/12/10/zfs-administration-appendix-c-...

Any good ideas on how one might fix this incorrect "common wisdom"?

Thank you! I was always a bit puzzled why the Sun engineers would not verify against the on disk checksum, but it made some sense that in a server setting ECC can be assumed.

By the way, the above "insane" scenario comes from the freenas forums

http://forums.freenas.org/index.php?threads/ecc-vs-non-ecc-r...

and is used to motivate why ZFS should have ECC ram. I am glad to hear that is much less of an issue than it's made out to be.

As far as I've understood, the gist of the "ZFS without ECC is scary"-mantra is that one bad memory location (say a flaw that results in a word always getting zeroed) might corrupt all your on disk data due to scrubbing ("read data, compute checksum, write data, repeat") Is this in fact a non-issue with ZFS?

>The root of both bugs was a design flaw: the decision that >git.kde.org was always to be considered the trusted, >canonical source.

It seems that an even bigger design flaw is that they (still) aren't doing regular backups. The mirroring of course provides some redundancy, similar to what raid does, but as they say: "raid is not a backup solution".

I don't know if you want a hint, but... If you do it the right way, no tweaking is needed at all. (The puzzle can be viewed as a very nice illustration of ergodic trajectories.)

The answer to "Who's fastest when?" is a bit complicated - you can find a nice picture of the "champion algorithm" for different ranges at

http://gmplib.org/devel/log.i7.1024.png

More context and explanation can be found at: http://gmplib.org/devel/

Short summary: Toom-Cook is nice because you have many parameters to play with.