Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror
Power

Giving Up Alternating Current 357

An anonymous reader writes: Yesterday we discussed Soylent, the artificial food substitute created by Rob Rhinehart and his team. As it turns out, this isn't Rhinehart's only unusual sustainability project. In a new post, he explains how he gave up on alternating current — a tough proposition for anyone living in the U.S. and still interested in using all sorts of modern technology. Rhinehart says, "Most power in the US is generated by burning coal, immediately squandering 67% of its energy, then run through a steam turbine, losing another 50%, then sent across transmission lines, losing another 5%, then to charge a DC device like a cell phone another 50% is lost in conversion. This means for 100 watts of coal or oil burned my phone gets a mere 16."

The biggest hindrance was the kitchen. As you might expect for the creator of Soylent, he doesn't cook, and was able to get rid of almost all kitchen appliances because of that. He uses a butane stove for hot beverages. He powers a small computer off batteries, which get their energy from solar panels. For intensive tasks, he remotes to more powerful machines. He re-wired his apartment's LED lighting to run off direct current. Have any of you made similar changes? How much of an effect does this really have?

Comment Re:It's unfortunate they have to shut down (Score 1) 177

Seriously, this is an intermediate subject in crypto and filesystem design. I can only give you hints. If you really want to understand this, some study on your part is required.

For example, one thing you do to prevent crafted collisions when you do not control the input to a hashing-scheme is to add a "salt" that is not accessible to the attacker. This makes even broken crypto hashes exceptionally resistant against crafted collisions. It is a well-known technique and also used in conventional hash-tables with non-cryptographic hash-functions to prevent algorithmic complexity attacks. As to random collisions, they do not happen in practice even with weaker crypto-hashes, as long as the hash-length is tailored to the maximum filesystem size.

Some level of understanding is rightfully required to make claims in this space. I do not see that level in Valery, and hence I call here "not so smart". If you take exception with that, come right out with it and do not hide behind technicalities.

Comment Re:It's unfortunate they have to shut down (Score 1) 177

You do not write a "meh" paper on an important design aspect in an area you are currently working if you are smart. Instead you try to understand the subject better and then write a good paper. As to wrong, it needs a bit more than a first glance and it needs some understanding of the crypto and computer hardware involved. The paper, as it is, shows "ego". It does not show "smart", but the absence of it. It is also not the only indicator of that problem in her person. This being /. I am not going to do more research for you.

Comment Re:It's unfortunate they have to shut down (Score 1) 177

It seems like she does understand this, but is saying that the comparison of collision rates to hardware failures is not appropriate.

That is one of the criticisms I have, because the comparison is appropriate. You do need to understand how to do it right, but she does not. Her explanation is bogus. She does not understand the statistics. Given that she was working as a file-system developer at that time, this is not acceptable and clearly shows that she has no understanding of her own limits.

Comment Re:Why children should NOT be taught to code (Score 1) 116

Hmm. Difficult question. I learned PASCAL in school (and knew BASIC and some assembler before), but it was taught by an enthusiast teacher and we were all there in our spare time, no grades or anything. And I self-learned C from a book not long after, because PASCAL back then was limited to 64k data and I needed more.

Still, I do not think COBOL is a good idea. A combination of PYTHON and C may serve the same goal (just require real understanding for most of what is taught), without putting off the ones with the talent to learn.

Comment Re:It's unfortunate they have to shut down (Score 1) 177

On example is her writing on compare-by-hash. It has been a while and I am currently not finding the original text anymore, but at a quick glance this paper seems to be the same thing: http://valerieaurora.org/revie... I have no idea (and currently no time to check) whether the emotional arguments and faulty statistics I found in the text I read are also in the PDF.

Now, compare by hash is perfectly fine if you do it right. In that case the computer producing bit-errors and the like while you do the hashing for a comparison is more likely than getting a hash collision. Yet for some reason Valery seems to not understand that, or at least did not back then.

Comment Re:"save environment for women" (Score 1) 177

Add neck- and back-problems to that. But getting your work criticized in clear language? Being able to take that is called "professionalism". And nobody will put porn into a presentation, unless it was on-topic. It is more likely that these women cannot stand that about 100% of men like porn (and not so few women), and they want to fight that preemptively.

Comment Re:It's unfortunate they have to shut down (Score 2) 177

I read some of Valerie's technical texts a while back. Driven, focuses, maybe, but smart, not so much. She even gets intermediary technical things wrong that are quite obvious to any precise thinker. Then she uses emotional appeal to cover up her lack of arguments and to convince the reader anyways. That is a real problem, as physical reality is quite unforgiving to those that do not understand it.

"Well, it don't make the sun shine, but at least it don't deepen the shit." -- Straiter Empy, in _Riddley_Walker_ by Russell Hoban

Working...