NASA proves once again that, for it, the impossible is not even difficult.

Robert Myers · 2011-02-09T16:53:18+00:00

In this case, proving a negative about unexpected acceleration ofToyota cars:Sudden acceleration in Toyota vehicles not an electronic issue, U.S.study findsI had thought of calling this post a Car Talk question for When I got my car back from the dealer from servicing the last time,it did something weird and a little scary, like suddenly decide thatit didn't want to go anywhere right after I had pulled out of aparking spot. The service manager offered to examine the car again,but I told him I'd rather see how difficult it was to reproduce theproblem.The problem occurred just twice and hasn't happened again in threemonths. My suspicion is that the "servicing" put my stateful vehicleinto some weird state that was not easy to duplicate, and that, havinggone twice through some critical section of code, the car hasforgotten all about the experience.The only people I know of who do enough testing with machines that arestateful in ways that are hard even to enumerate would be people whowork with microprocessors. I wonder if anyone at a water cooler atNASA has noted that it wasn't Intel, but someone else, who discoveredthe problem with the Sandy Bridge chipset.Now, I'm a bit of a cranky old carmudgeon, and my instinct is to shrugmy shoulders at my car dealer and at NASA and say, "Oh, well, I neverthought you knew what you were doing, anyway." Intel doesn't knowwhat it's doing either, but by now it either knows it or should knowit. NASA has proven beyond a reasonable shadow of a doubt that it isuneducable.My question is this: does anyone in this business believe that it ispossible to uncover all corner cases by any plausible testing protocolthat someone would actually spend the money for? By "all cornercases," I mean enough that corner cases would never be discovered inthe wild after having escaped discovery in the testing labs.Robert.

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stevech 15 years ago

Jog your memory of some few but noteworthy software design errors by NASA/contractors:

1997: Mars Pathfinder. Data Losses, repeated. Error in RTOS, task scheduling priority inversion yielding deadlock. System hardware/software transient yielding a case not practical to analyze, predict or simulate.

1999: Mars Climate Orbiter: Orbit insertion failed. Error in conversion from imperial to metric units.

1999: Mars Polar Lander: System of Systems logic error causing premature engine shutdown in descent.

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IMO: System/software errors are proportional to the number of software engineers working the same project. Fewer is always better.

To Err Is Human. To Truly Screw-up Takes A Computer.

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Paul Colin Gloster 15 years ago

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MitchAlsup sent on February 14th, 2011: |

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Robert Myers 15 years ago

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Actually, 30 degrees is 1/sqrt(3), which is even steeper than 6/12. A

6/12 roof pitch might be scary for the average person, but not for anyone who has spent any amount of time working on roofs.

Today was warm enough that I could venture from my home for any reason other than to get into my car or to shovel snow. The steepest driveway within steps of my home is about 3 in 10 (or 4 in 12). Lots of sand on that driveway now. There is a road I have to walk further in icy conditions to get to that I estimate to be even steeper and which also has some pretty steep drives on it. Going down that road in snow and ice, you want to keep your foot off the brake (I have a manual transmission). I have never ventured to approach that roadway from the steepest direction in snowy conditions going uphill. When the weather is warmer still, I will venture forth with my carpenter's level. ;-)

Robert.

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Colin Paul Gloster 14 years ago

Paul Colin Gloster sent on February 14th, 2011: |-------------------------------------------------------------------------| |"On 2011-02-12, Del Cecchi wrote: | ||-----------------------------------------------| | ||"Actually you can kill someone with a bicycle."| | ||-----------------------------------------------| | | | |Maybe we should restrict normal modes of transportation | |to walking and pogo sticks. | | | ||-----------------------------------------------------------------------|| ||" Hell, I damn near killed || ||myself. Anything that causes your head to strike a hard surface at any|| ||significant velocity, like falling down from a standing position, will || ||do it. Wearing a helmet is a small amount of protection. I got a nasty|| ||concussion and was wearing a quality bike helmet when I hit a patch of || ||sand." || ||-----------------------------------------------------------------------|| | | |Wow. Thanks for the heads up (ho ho). | | | |I use a Limar helmet. What brand of helmet were you using, so that I | |can avoid it when I shall need a new one? | | | |[..]" | |-------------------------------------------------------------------------|

Hi!,

I never received a response to this. My Limar helmet is old and I could do with replacing it some year. A car crashed into the bicycle which I was cycling today, but I survived and I would like advice of inferior helmets to avoid buying.

Yours sincerely, Colin Paul Gloster

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NASA proves once again that, for it, the impossible is not even difficult.

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