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

 



Forgot your password?
typodupeerror

Comment Cost of fiunding bugs != cost of fixing them. (Score 5, Insightful) 95

Browsers have very large installed base. There are enough bug spotters even if a very small fraction of them actually hunt and report bugs. Even then, the bounty is for finding the bugs, not fixing the bugs that includes the cost of coming up with a fix, verifying it fixes the problem, testing to make sure it does not create new problems and rolling out the fix.

Comment I have seen something similar. (Score 3, Interesting) 323

Back in the day when I was with the ministry of defense we lost a vehicle due to an error like this. They had changed the vendor for the gyros of the roll sensor. The new gyros had the voltages in the reverse sense. It is possible one vendor was European and the other was American. They wired it according to the sense of the old vendor. So the control input to the ailerons would add to the roll instead of counteracting it. The RPV crashed 1.5 seconds after launch.

In the postmortem the flight director started with, "... we sadly lost the vehicle after a flight of 1.5 seconds ...". The mission director interrupted, "What flight? The damned thing had a 6000 Kg[sic][*] rocket booster. You can put it under a 3 ton rock and it will 'fly' for more than 2 seconds..."

[*]He should have said 6000 Kgf-sec, because that was the impulse delivered by the twin rocket boosters each 1500 Kgf thrust burning for 2 seconds.

Comment Not going to available in USA (Score 1) 353

Because it has a top speed of 99mph, it has to obey all the passenger car safety requirements. If they use some software to limit the speed to 25mph, they can sell it USA as a Lowspeed vehicle. But anyway they are only planning to make 250 vehicles for the European market.

I think in a decade or so, all the cars will get an electric motor as the zeroth gear.If the IC engine has work only above 5mph or 7mph they can tune it completely differently and improve fuel economy by 50% easily. Much of the fuel economy of the Prius comes from the engine that does not have to work below 10 mph. It would not be too expensive to store enough juice to pull the car up to 5 or 10mph a few times.

Comment Re:We need a new class of 'ultralight' cars (Score 4, Insightful) 353

That is the concept behind Tata Nano. It is very cheap and you could barely call it a car. But its CEO (at that time, not sure who is running the show now) Ratan Tata said "It is not an unsafe car. It is a safe motor cycle with four wheels and a roof" (I am paraphrasing). In India it is common to see an entire family, dad+mom+two+kids all piled up in one motor cycle or a scooter dodging potholes and weaving in out of traffic. Yes, such cars exist. But it is very unlikely to pass any safety test in USA/Europe/Japan/Korea.

Comment Re:Salt is NOT benign (Score 2) 120

Salt was not cheap for Romans. It was so rare Roman soldiers were actually paid in salt. The Latin word for salt, salar is the root of the word salary. They certainly did not have it at enough quantities to poison the land or people. They probably sprinkled the conquered cities with salt in some kind of symbolic ritual. Talking about symbolic military ceremonies involving salt, nothing beats the induction ceremony of the Gorkha soldiers. These tribals pledge fealty to anyone who has given them salt. At the induction ceremony they line up, the commanding officer in full dress uniform marches along the ranks, with another colorfully dressed sergeant bearing a tray of salt. NCOs bellow commands for the inductees to open their mouth and the CO sprinkles salt into their mouth. For all that pomp and circumstance it looks ridiculously funny.
Supercomputing

Video Meet the Stampede Supercomputing Cluster's Administrator (Video) 34

UT Austin tends not to do things by half measures, as illustrated by the Texas Advanced Computing Center, which has been home to an evolving family of supercomputing clusters. The latest of these, Stampede, was first mentioned here back in 2011, before it was actually constructed. In the time since, Stampede has been not only completed, but upgraded; it's just successfully completed a successful six months since its last major update — the labor-intensive installation of Xeon Phi processors throughout 106 densely packed racks. I visited TACC, camera in hand, to take a look at this megawatt-eating electronic hive (well, herd) and talk with director of high-performance computing Bill Barth, who has insight into what it's like both as an end-user (both commercial and academic projects get to use Stampede) and as an administrator on such a big system.

Comment If you need it you are doing it wrong. (Score 5, Insightful) 211

If your spreadsheet needs a gpu to speed up calculations, you are probably misusing spreadsheets. I know most accountants love the spreadsheet and they make insanely complicated things using spreadsheets pushing it far beyond what these are designed to do. But if you have a spreadsheet that needs this much of cpu time to recompute, you should probably be using a full fledged data base with multiple precomputed indexing.

Comment Re:RAM 1500 'Infotainment' system (Score 1) 317

The nav system uses the same display as their rear view camera. I actually ordered their top-view camera system in addition too. Just for fun. They use two cameras on the wing mirrors and the rear view camera to display a composite image as though you are floating above the car and looking down. Quite cool to look at and my wife liked it. But the damn wing cameras do not turn and look backwards to provide some blind spot protection. Their idea of blind spot protection is radar mounted in the rear bumper.

Comment Re:RAM 1500 'Infotainment' system (Score 1) 317

BMW sees such customers all the time. In most other luxury brands such customers will pick a car from a different badge (Toyota instead of Lexus, Chevy instead of Cadillac). BMW has only one badge. So they call these cars "driver cars". Enthusiastic customers who can't afford all the fancy stuff. BMW caters to them. And ithat takes care of those off-beat guys who could afford fancy but still obstinately refuse to buy it.

Comment Re:Car companies innovate very poorly. (Score 1) 317

You are right in claiming electric motors are inherently more reliable by an order of magnitude or more. In Washington PA there is a museum for trollies and street cars. There there is a picture of twin brothers from some Eastern European country. Their claim to fame? They wound an electric traction motor for a trolly car in 1918 and it never needed to be rewound till the car was scrapped in 1984. All these years that motor dragged the trolley car through mud and snow and heat all through the streets of Pittsburgh without ever needing to be rewound. (Winding the coils into to the armature of the motor is the equivalent of rebuilding an IC engine). The management would be averse to such technologies. They actually used the term "planned obsolescence" seriously in management presentations.

But there is an area where they were competing intensely, with no holds barred and no managers messing with them. That was the acceleration quarter-mile time and 0-60mph time got them the bragging rights. They took this pissing contest seriously. Here we are talking about virtually unlimited budgets, no interference from bean counters and sales critters. Adding an electric boost at below 5mph would have added to the over all complexity and service revenue would not be impacted. But still they did not have the imagination to do it.

Comment Re:Car companies innovate very poorly. (Score 1) 317

Battery technology only limited the range of pure electric cars. The cars produce plenty of excess power, and they could easily store enough juice to accelerate the car from stand-still to 10mph. The electric motor would simply assist the first gear, or it could even be called zeroth gear and the IC engine engaging the wheels only beyond 7mph or 10 mph. How much juice you need to do it? Almost all the problems of IC engines occur because IC engines can not run at 0 rpm. Till someone something cranks it up to idle rpm, (900 or so) the engine would not run. They need to let the engine slip and engage the wheels through a clutch till the 1:16 reduction ratio allows the engine to engage the wheels without slip. Then it accelerates. Why the hell did they not soup up the starter motor, already in the power train to not just start the engine, but also to propel the car to 5mph? The batteries can easily store enough juice to do it 10 or 15 times, and the battery could be fully recharged in 1 minute of regular driving.

You could accuse me of Monday-morning-quarterbacking with the benefit of 20-20 hindsight. And you would be right. But I am not an auto engineer. There were auto engineers fighting the 0-60 mph time battle for all the car companies all the time. They should have thought about it and implemented it. Cost was not a limitation. I am talking about Porches and BMWs. Weight is not an issue. These monster cars are all engines-and-wheels with tiny cockpit for the driver to squeeze in. Complexity is not an issue. These engines are V12 and V8 engines with thousands of moving parts with twin turbo supercharging with intercooler. These beasts would malfunction if you looked at them wrong.

Look at their supercharging. Electric superchargers were well known and were actually used in airplane engines since 1930. Still these engineers are so averse to electricity or so afraid of it, they would rather use a turbine mounted in the exhaust manifold and use it to power a compressor to supercharge the cylinders. Look at the complexity. At this point they might as well dispense will all the cylinders and pistons and camshafts and try to become a pure gas turbine engine. That is what these are. Exhaust turning a turbine, which turns a compressor, heck you got a gas turbine engine right there. All these pistons and cylinders do is to slow the damn thing down. If a simple combustion chamber is used and the turbines spin up to 30000 rpm, you got a jet engine. You can easily make a turbo-shaft engine. But these engineers were so wedded to the idea of cylinders and pistons, they did not make the jump. Of course, there is the turbo lag. I remember seeing Jay Leno riding a motor cycle made by strapping a couple of wheels to a discarded helicopter turning engine. He said, there is turbo lag on both ends. You turn the throttle off, and then the engine thinks about it for a minute before spinning down.

Comment Re:RAM 1500 'Infotainment' system (Score 1) 317

I just ordered a new BMW and the salesman could not understand why I would insist on ordering one without Navigation and the upgraded entertainment system and wait four weeks rather than pick one off the lot with all the fancy (fancy to the car guys) stuff. I told him BMW should stick to what it knows, IC engines and car bodies and keep its nose clear of things it has no idea of what fancy is.

Slashdot Top Deals

Unix will self-destruct in five seconds... 4... 3... 2... 1...

Working...