Follow Slashdot blog updates by subscribing to our blog RSS feed


Forgot your password?

Comment Re:Just delete it (Score 2, Insightful) 189 189

This. Links in email are dead to me. I don't follow them, my mail client doesn't follow them, it's just so many wasted bytes. And that includes e-cards from friends/relatives. You want to send me something, send it to me, don't ask a third-party to.

(Sure, I make an exception for links I'm expecting (have asked for) but even then I'll copy them to my browser. HTML in my email is turned off.)

Comment Re:Would have saved itself (Score 2) 220 220

Actually, it would have been super cool if the first successful recovery of the first stage had been an emergency abort!

Something like this actually happened on the fourth or fifth flight of the DC-X test vehicle. It had made several successful launches, hovers, and vertical landings and the test profile had it going to higher and higher altitudes and doing some interesting maneuvers. Anyway, on the nearly fatal flight, due to wind conditions in the launch area, hydrogen gas (it was LH2/LO2 fueled) collected near the base of the rocket and ignited in a mild explosion at launch, with the shockwave blowing off some of the DC-X's airshell. The rocket continued climb-out, shedding more pieces as it went, as the observers watched. Pete Conrad (the astronaut, who as part of the DC-X team was controlling the flight from the ground) calmly clicked the "abort" sequence on the control computer. The DC-X stopped its ascent, hovered to burn off fuel (to lighten the load on the landing gear) and then landed safely.

Try that with any other rocket. (The DC-X's engines were modified RL-10s, much more deeply throttleable than Falcon's Merlin engines.)

Comment Re:Holy Jebus (Score 4, Informative) 220 220

And the depressing thing is that every one of them is there to prevent recurrence of a dishonesty that actually took place in the past.

And sometimes it's not even dishonesty, just stupidity. This was probably more true in the earlier days of aerospace. In a book about the design and construction of the Lunar Module (I think it's Chariots for Apollo, but could be wrong) there's a section on how many of the subcontractors had to be taught clean-room and quality techniques. There's one episode where one of the Grumman managers goes out to some paint pigment company who happened to get the contract for the silver-zinc LM batteries (because they had supplies of the right materials) and sees the batteries being assembled -- in a dirty shed by people who are smoking cigarettes while doing the assembly. (They threw out the entire batch, trained everyone how to do things the aerospace way, and set up a clean room, and AFAIK there was never a problem with the LM batteries.)

On the other hand the ladies sewing space suit pressure garments at the Playtex Girdle factory knew the astronauts' lives depended on what they were doing, and did it right the first time.

Comment Re:Potholes? (Score 1) 183 183

Having to heat the road itself completely negates that, as there's a LOT of road out there.

Actually heating the road is easy, with a little creativity. I was going to suggest adding plutonium to the road mix, but the same end could likely be achieved more cheaply by just using nuclear waste. Solves the waste problem at the same time.

Of course, there may be some undesirable side effects....

Comment Re:MUMPS criticism (Score 1) 166 166

but it was invented in the 1970s, before the concept of OOP had even been invented.

If it really was the 1970s, then it came some years after SIMULA-67, aka "ALGOL with objects". (I.e., SIMULA-67 was to ALGOL more or less as early C++ was to C.)

Everything in CS is (probably) older than you think. Including many of its practitioners ;-)


New Letters Added To the Genetic Alphabet 74 74

An anonymous reader writes with this excerpt from Quanta Magazine: [A]fter decades of work, [organic chemist Steven] Benner's team has synthesized artificially enhanced DNA that functions much like ordinary DNA, if not better. In two papers published in the Journal of the American Chemical Society last month, the researchers have shown that two synthetic nucleotides called P and Z fit seamlessly into DNA's helical structure, maintaining the natural shape of DNA. Moreover, DNA sequences incorporating these letters can evolve just like traditional DNA, a first for an expanded genetic alphabet. In fact, the article continues, these new nucleotides can actually outperform their natural counterparts: "When challenged to evolve a segment that selectively binds to cancer cells, DNA sequences using P and Z did better than those without."

Comment Re:Probably an overreaction, but... (Score 2) 431 431

In Canada, a teen couldn't just go into a store and buy it, and even getting hold of large quantities of potassium nitrate was challenging.

Don't know how old you are, but when I was a kid in Toronto in the mid-1960s we could (and did) go down to the local drug store and buy potassium nitrate in 1-pound containers. Ditto sulphur, so long as you weren't stupid enough to try to buy both at the same time. (At least we never tried that, we just assumed that the cashier would be at least as knowledgeable as us and figure it out. Maybe not.)

Our sixth grade teacher did admonish us (not directly, but the class as a whole) about the dangers of such homebrew, with a few anecdotes of kids who had lost various body parts through doing stupid things like using metal implements to mix the stuff (sparks!), or treating it a bit too cavalierly.

Comment Re:Paranoia (Score 3, Informative) 431 431

Don't you know that most explosives work via a reaction with oxygen in the air?

Actually no, most don't, unless you're talking about fuel-air explosions (which can be bloody huge!). Most solid or liquid explosives use an oxidizer that's part of the mix -- or don't use an oxidizer as such at all, but rather their rather unstable molecular configuration degenerates to a lower energy state with much release of energy and component parts (most high explosives).

Comment Re:Microsoft loves Unix (Score 1) 265 265

"They ported the Unix for a Radio Shack system"


Xenix was based on a source license from AT&T (the original, not the renamed Southern Bell) of Bell Labs' Version 7 Unix. Microsoft also made Xenix ports available for a number of other systems.

Plenty of other companies also made licensed ports of V7, which they couldn't call Unix (or UNIX) because AT&T wouldn't license the trademark. For example, Amdahl made UTS which ran on their IBM 370 clones (as well as on IBM hardware).

Comment Re:Why do I get the funny feeling that (Score 2) 265 265

It probably comes from reading the licenses, which you should try sometime. Note also the word forked.

You take some BSD-licensed code, make changes to it (creating a derivative version), then GPL-license the derivative. Anyone is still free to find the original BSD sources and make their own derivative, but they can't do anything with the GPL-licensed fork without following the GPL -- which includes GPL'ing any work derived from that.

Of course unless the changes introduced by the fork are particularly compelling, nobody is going to care. But it's still a possibility. The BSD licence allows it, just as it allows someone to make totally proprietary derivatives.

Comment Re:Idiotic Question! Answer: Price, Range, and .. (Score 1) 688 688

Well, it's still a better car in most ways. People don't only buy the cheapest car.

Is your car already air conditioned when you get into it? The Leaf lets you set that. You're literally more comfortable in a Leaf than you would be in most cars. And the difference in running costs is not extreme. And yes, the equation in the UK is different, gas is more expensive, and there's more charging stations. But America will catch up, and the Leaf/electric cars are getting ever cheaper.

But no single car is right for everyone; but I do find the extremely common hatred amusing.

Comment Re:Idiotic Question! Answer: Price, Range, and .. (Score 1) 688 688

I checked into it. The premature failure of the battery in hot climates was an issue with the 2011, 2012 models, but Nissan reformulated the battery chemistry and the 2013 version doesn't really have the issue (the degradation happens at 1/3 the rate).

They also extended the warranty to cover back to the 2011 models, and if it happens they replace the battery back to full charge state.

Even when they do wear out, they're selling replacement batteries at (what seems to be) slightly below cost. The batteries are getting cheaper all the time anyway (8% per annum), and provided you do a reasonable mileage, the Leaf is still cheaper and more reliable than using a hybrid.

"Summit meetings tend to be like panda matings. The expectations are always high, and the results usually disappointing." -- Robert Orben