Follow Slashdot stories on Twitter


Forgot your password?

Comment: Re:Failsafe? (Score 1) 220

by PPH (#49605641) Attached to: Long Uptime Makes Boeing 787 Lose Electrical Power

failsafe mode

Well, it is for a single generator. The power source is removed from the system so that not subsequent failures can damage the aircraft. Problem is: This applies to a single generator, not the entire aircraft. Aircraft power systems are designed so that an alternate source can take over for the failed one. But if they all go off line together, not so safe.

Comment: Re:Enough of this (Score 1) 220

by PPH (#49605605) Attached to: Long Uptime Makes Boeing 787 Lose Electrical Power

There's the principle of lessons learned. And not rewriting everything from scratch. This problem has been addressed and solved in numerous RTOSs and libraries. And even if these could not be used, simple things like overflows, underflows and other sorts of out of range variables are supposed to be caught by the sorts of rigorous analysis avionics s/w is supposed to be subject to. That this was caught in a lab test (and this far after the system went into service) is problematic as well. The complexity of most software (particularly real-time apps) rules out being able to cover all combinations of use cases by overall system tests.

Comment: I didn't know ... (Score 1) 103

by PPH (#49596091) Attached to: Climatologist Speaks On the Effects of Geoengineering

... climatology included a study of proctology.

Because Robock is pulling the threat of nuclear war right out of his ass. Sadly, the nations most likely to suffer from geoengineering gone wrong, or failing to fix the climate 'problem' using geoengineering are too small and weak to threaten anyone with nukes. The few big players in the nuclear game are also big enough globally that, unless we have their cooperation, unilaterally trying to tweak the climate just won't work.

We can do what we want. But unless China, India and Russia get behind such an effort, they can pretty much push the climate any way they want.

Comment: Re:Now they will have two fiber networks? (Score 1) 179

Currently, there is no mechanism in place to track demand. Other than what the broadband companies do for themselves. With regulated utilities (which broadband providers should become), service requests and response times are tracked and reported to various utilities commissions.

If there were some centralized point where requests for service could be accumulated, then Comcast and its ilk couldn't claim that there is insufficient demand in a particular area to justify construction.

Comment: Re:What about ADS-B spoofing? (Score 1) 159

by PPH (#49593999) Attached to: US Switches Air Traffic Control To New Computer System

That would be a kind of 'false positive'. A report of an aircraft in a position where there is none. Soon, false negatives (no ADS-B where surveillance radar shows one) will be investigated by the dispatch of armed fighter aircraft. False positives can be handled in a similar manner by tracking the source of spoof signals and dispatching the appropriate countermeasures.

Comment: Re:Odd definition of "disruptive" (Score 1) 249

by PPH (#49587483) Attached to: Bitcoin Is Disrupting the Argentine Economy

In this case, disruptive means that the people who need to prop up the peso/dollar exchange rate to pay back loans denominated in dollars will get screwed. Because the supply of pesos flowing through the system available for the banks to skim will dry up. And US investment banks who took risks wil have to renegotiate loans. Or accept default.

And if there's one thing we know about wealthy investors: They never take a loss on a gamble. Someone else must be found to make them whole.

A method of solution is perfect if we can forsee from the start, and even prove, that following that method we shall attain our aim. -- Leibnitz