Please create an account to participate in the Slashdot moderation system

 



Forgot your password?
typodupeerror
×

Comment Mysterious "Aurora" attack not so mysterious. (Score 1) 50

There's nothing mysterious about this. The problem is that if someone gets control of circuit breakers for large rotating equipment, they may be able to disconnect it, let it get out of sync, and reconnect it. This causes huge stresses on motor and generator windings and may damage larger equipment. This is a classic problem in AC electrical systems. A more technical analysis of the Aurora vulnerability is here.

The attack involves taking over control of a power breaker in the transmission system, one that isn't protected by a device that checks for an in-phase condition. Breakers that are intended to be used during synchronization (such as the ones nearest generators) have such protections, but not all breakers do.

Protective relaying in power systems is complicated, because big transient events occur now and then. A lightning strike is a normal event in transmission systems. The system can tolerate many disruptive events, and you don't want to shut everything down and go to full blackout because the fault detection is overly sensitive. A big inductive load joining the grid looks much like an Aurora attack for the first few cycle or two.

There's a problem with someone reprogramming the setpoints on protective relays. This is the classic "let's make it remotely updatable" problem. It's so much easier today to make things remotely updatable than to send someone to adjust a setting. The Aurora attack requires some of this. There's a lot to be said for hard-wired limits that can't be updated remotely, such as "reclosing beyond 20 degrees of phase error is not allowed, no matter what parameters are downloaded."

Comment Web programming sucks. (Score 1) 608

Ignoring the racist whining, he has a point. Web programming really sucks. Even web design sucks.

HTML started as a straightforward declarative layout language. Remember Dreamweaver? Macromedia's WYSIWYG editor for web pages. It was like using a word processor. You laid out a page, and it generated the page in HTML. It understood HTML, and you could read the page back in and edit it. Very straightforward. You didn't even have to look at the HTML. Back then, Netscape Navigator came with an HTML editor, too.

Then came CSS. DIV with float and clear as a primary formatting tool (a 1D concept and a huge step backwards from 2D tables), Javascript to patch the formatting problems of CSS, absolute positioning, Javascript to manage absolute positioning... The reaction to this mess was to layer "content management systems" on top of HTML, introducing another level of complexity and security holes. (Wordpress template attacks...)

It's as bad, if not worse, on the back end. No need to go into the details.

All this is being dumped on programmers, with the demand for "full-stack developers" who understand all the layers. Cheap full-stack developers. Usually for rather banal web sites.

Not only is this stuff unreasonably hard, it's boring. It's a turn-off for anyone with a life.

Comment Being a quant in the early years. (Score 4, Interesting) 96

His fund has an impressive trading record. He had the big advantage of starting early, in 1982, when almost nobody was doing automated trading or using advanced statistical methods. Their best years were 1982-1999. Now everybody grinds on vast amounts of data, and it's much tougher to find an edge. Performance for the last few years has been very poor, below the S&P 500. That's before fees.

The fees on his funds are insane. 5% of capital each year, and 45% of profits. Most hedge funds charge 2% and 20%, and even that's starting to slip due to competitive pressure.

Simons retired in 2009. You have to know when to quit.

Comment Re:What happened to Scheme? (Score 1) 415

Abelson and Sussman is a delightful book for programming theorists. Scheme is a big improvement over Common LISP. Learning Scheme from Abelson and Sussman is straightforward for people who can get into MIT.

This is not most of the programming population. As someone else pointed out, programming today is mostly the creation of glue code to tie together a number of (usually buggy) components. Neither the webcrap crowd nor the appcrap crowd needs Scheme. In fact, if you have that strong a theoretical background, you tend to overdesign simple programs.

Comment Re:Bah humbug. (Score 1) 415

a bad intermediate language

It, like COBOL, is only bad if you make it bad. (Shelly & Cashman -- may their non-existent souls burn in non-existent Hell for all eternity! -- made COBOL bad. Real experts in the language showed me how good and capable it (even the much maligned COBOL-74) the language. -85 was even better.)

Comment Good idea (Score 5, Insightful) 415

Python isn't a bad first language. It has all the important advanced concepts - objects, dictionaries, closures, and threads. The syntax is reasonable. Some people are bothered by the forced indentation, but for new programmers, it will seem natural.

Most of the problems with Python are performance related. They come from obscure features of the language, such as the ability to do "getattr" and "setattr" on almost anything, including objects running in another thread. So everything has to be a dictionary. (This is sometimes called the Guido von Rossum Memorial Boat Anchor.) PyPy is struggling hard to overcome that, with some success. (The optimization approach is "oh, no, program did Obscure Awful Thing which could invalidate running code" - abandon compiled JIT code, shift to backup interpreter, flush JIT code cache, execute Obscure Awful Thing, wait for control to leave area of Obscure Awful Thing while in backup interpreter, rerun JIT compiler, resume running compiled code.)

Comment Bah humbug. (Score 1) 415

I like Python, but BASIC on a C-64 VM is what they should first learn.

No need to become an expert in it; maybe just 1/2 of a semester. But with line numbers analogous to memory addresses, GOTO essentially a branch, and GOSUB like subr, they'd get a better sense of what is actually happening in the "h/w", before going to a super-HLL like Python.

Comment no rest no peace (Score 1) 65

These 3D whizmos, like for example LEAP motion (incredibly cool), all work great.... for about 20 minutes. Then you put them in the drawer because they require too much muscle coordination and energy to operate. in contrast when you REST your finger on a scroll wheel or REST your hand on a mouse it is not merely not moving, it is at rest in 3 dimensions. it only takes a small effort to move it, but you are not having to run a whole lot of muscles in coordination to keep the hand or finger in a constant position. it's hard to poise your hand in empty space. In the old days, good typists could do this with hands poised over the KB and fingers hovering above the keys. Most people now days use palm rests or put pressure on the keys. those old time secretarial pool typists had to sit up straight and brace their feet on the floor to pull that off. Girdles probably helped!

the first successful mouse replacement will have that feature. Perhaps something with haptic feedback to support your finger a little till you really want to move it.

personally I suspect the some sort of eye motion or maybe a joystick like thing will be the first 3D controller that people can use for long periods.

Slashdot Top Deals

What this country needs is a good five dollar plasma weapon.

Working...