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Comment: Re:Seized? (Score 1) 162

by gwern (#45247287) Attached to: FBI Seized 144,000 Bitcoins ($28.5 Million) From Silk Road Bust
If you can beat the general network for 120 days (and increasing, and also the difficulty is generally increasing as well, making 120 days even more of a lower bound), then I don't see how that is meaningfully different from being able to do so indefinitely. A third of a year is a pretty long time.

Comment: Re:Seized? (Score 1) 162

by gwern (#45247079) Attached to: FBI Seized 144,000 Bitcoins ($28.5 Million) From Silk Road Bust
You are not talking about the 51% attack as generally understood. You can't, because then you are talking about requiring far more than 51% of power for a few blocks: you need 51% of the network indefinitely to build a longer blockchain *and* you also need to defeat the checkpoints used by most clients & miners *and* defeat whatever community-based mechanisms happen.

Comment: Re:Seized? (Score 1) 162

by gwern (#45245627) Attached to: FBI Seized 144,000 Bitcoins ($28.5 Million) From Silk Road Bust
No, you can't 'rewrite history'. What the 51% attack lets you do is block any additional transactions by refusing to produce blocks with those transactions in them, which lets you do double-spends. However, you cannot spend someone else's coins because you cannot create valid signatures without their private keys.

Comment: Re:...Or an arms race (Score 1) 646

by gwern (#31589116) Attached to: SSD Price Drops Signaling End of Spinning Media?

Excess capacity summons its own uses.

You assume that your movies and videos cost only their storage space. But what if you switch to a finegrained snapshotting filesystem? That could use up a great deal of space depending on how much you download, modify, and delete.(With space no longer an issue, longevity becomes an issue. I'd rather lose half the space on an oversized hard disk if that means that 20 years from now I will still have my files.)

You assume you'll only store what sort of things you currently do. But what if you scan all your books to save space? High resolution book scans can easily consume hundreds of megabytes a piece. I was thinking of scanning an art book at best resolution, and calculated that its ~500 pages would use up around 20 gigabytes in TIFFs.

And what of new electronic stuff? Lifelogging (http://en.wikipedia.org/wiki/Lifelogging) is currently the stuff of experiments and early tentative ventures by the likes of Gordon Bell. But just yesterday the NY Times covered a small camcorder which uses 2GB for 72 minutes of video and costs ~$200; not useful, no, but useful in a few more years/cranks of Moore's law. Lifelogging is easily a gigabyte a day. That's peanuts, of course, and ever cheaper - but the point is that it will soon burst the seams of your 500GB drive.

And so on. Right now you think your needs are met. But there's always something more one could store, and needs change. Maybe, just maybe, you *are* right and 500GB is all you'll ever need; but for the rest of us, that's as sensible as Gates's mythical '540k is enough for anyone'.

Comment: Re:An easier plan (Score 1) 555

by gwern (#31484886) Attached to: US Intelligence Planned To Destroy WikiLeaks

> Though my idea would be to have the justices only review secrets that specifically pertain to legal cases.

And what is to stop regulatory capture*? Your court is akin to the FISC authorizing wiretaps, and it is famous for rarely ever rejecting requests:

* http://en.wikipedia.org/wiki/Regulatory_capture

Comment: Re:Here's A Tip, Folks (Score 2, Funny) 313

by gwern (#30912752) Attached to: Darwinian Evolution Considered As a Phase

> Evolution requires that there be variation in individuals, and that there be selection.

That's odd. My vague memories of reading people like Dawkins keep whispering things like 'evolution is changes in allele frequency in a gene pool', which is obviously nonsense because that says nothing about 'individuals'.

Comment: Re:A case of the pundays (Score 1) 376

by gwern (#30578418) Attached to: Happy Birthday, Linus
There are many cases where unilateral movement to a desired equilibrium is worse than useless; it's stupid to suggest that *obviously* copyright is not one of them. It's like saying 'if South Korea really wants peace, why isn't it disbanding its military and kicking out the US?' Because that only helps the other guy, does nothing to bring about the desired outcome, and will screw you the heck up.

Comment: Re:Why do we sleep? (Score 1) 164

by gwern (#29693647) Attached to: Alzheimer's Disease Possibly Linked To Sleep Deprivation
Healthy old folks may be useful for humans. That would be a great explanation - if humans were the only things to sleep. Why do all sorts of animals which don't even have social groups, much less the ability to learn from each other (or anything to learn), sleep? Further, what sort of incredibly massive advantage are 'we' deriving from old people that in exchange we are willing to piss away at least a third of our life and render ourselves incredibly vulnerable?

Gee, Toto, I don't think we're in Kansas anymore.