crocal

16 ms·

121.
by crocal 8y ago
It can be abused, but it should not be possible if the process driving certification of such system is followed properly. The standards define checks and balances designed precisely to detect such abuse. In particular, the pilot’s rate of e
122.
by crocal 8y ago
Depending on the mode of operation, the pilot will or will not be part of the redundancy. The trick in this type of application is the management of mode transitions. When sensors fail, the system will transition to degraded modes of operat
123.
by crocal 8y ago
Yes there is. If you put too many sensors then there is always one in need of repair. And then it becomes dangerous: the pilot and maintainer ignores the alarm, delay replacement, leading slowly to a failure. This is why the redundancy choi
124.
by crocal 8y ago
I am a designer and implementor of vital speed and distance measurement systems, with triply modular redundancy, used in mass transit application. I cannot even imagine what the designers of this thing are going through now. It must be terr
125.
by crocal 8y ago
It’s not that simple and indeed. See my response above.
126.
by crocal 8y ago
Usually the safety requirement will mention a mandatory reboot period that will be somehow related to a power of 2... Damn integer counters...
127.
by crocal 8y ago
Ah and yes of course the software is checksumed and you must verify the sum to make sure you load what has been certified and not some random piece of $£%# pretending to be it.
128.
by crocal 8y ago
Yes. I deliver such software. The downloading can be done over a network, however there should always be another mechanism in place to ensure only an authorized version runs. For example the vital computer compares a coded key compiled in t
129.
by crocal 8y ago
You can use 2 dbs if you apply the STONITH principle (Shoot The Other Node In The Head). Typically, when one node decides to be master, it can switch off with certainty the other one. Routinely used in HA (Highly Available) industrial appli
130.
by crocal 8y ago
Presented like this, I’m not sure if it’s a bug or a feature.
131.
by crocal 8y ago
Yes, and so you do not need three sensors to have a safe system in certain applications. It is sufficient to fail safe.
132.
by crocal 8y ago
This could be true in avionics where availability and safety are more or less the same. In other applications where there is a fail safe mode like nuclear (stop fission) or land transportation (hit the brakes), you do not need that. The sta
133.
by crocal 8y ago
Nope. Even if it were true in avionics (not my trade), not « any » safety system need triple redundancy to be safe (e.g. safety relays).
134.
by crocal 8y ago
« You need at least 3 redundant sensors in any safety critical system « Huh? Says who?
135.
by crocal 8y ago
And by killer carps. Never turn your back on carps. They want you dead! Explanation: http://dwarffortresswiki.org/index.php/40d:Carp
136.
BART running at reduced capacity due to computer problem(m.sfgate.com)
1 points by crocal 8y ago|0 comments
137.
by crocal 8y ago
Same bingo. My hypothesis (at least for the Facebook I see, that is of course a minuscule fraction) is that FB is mostly used now by people with an agenda (self promotion, spreading of an ideology, marketing, political campaign, whatever).
138.
by crocal 8y ago
FWIW, Nuclear fuel reprocessing tech has been developed for that. I know the French version. It shrinks and stabilises the waste in the form of a special form of glass (of course radioactive). The entire waste generated since 50 years fits
139.
by crocal 8y ago
This. I nicknamed this plane the « magic carpet ». It does not feel at all like you are taking off or landing. More like a train moving in 3 dimensions.
140.
by crocal 8y ago
I wonder how many Americans know about Buck Danny. This is after all a 50 years old Belgian graphic novel starring a US Navy pilot! « Fire from the sky » trilogy by Charlier and Bergese is unbelievably cool.
141.
by crocal 8y ago
Analog in python: https://docs.djangoproject.com/en/2.2/topics/migrations/
142.
by crocal 8y ago
Printer is coming...
143.
by crocal 8y ago
It is an automatic train supervision system for a metro line. It tracks and displays the position of trains and automatically routes them depending on schedule, delays and incidents. It also offer control and commands of the traction power
144.
by crocal 8y ago
You won’t be disappointed. I have an Erlang/OTP system in operations since nearly 10 years. Exactly zero downtime since first day of operation. And we did upgrades and change of hardware. The customer is in love.
145.
by crocal 8y ago
I respectfully disagree. Napoleon should be primarily remembered for the “Code Civil”. That stuff is a towering good deed, and dwarfs any battle won or lost. It’s reported that Napoleon himself admitted that, but I never could confirm the v
146.
Virgin Hyperloop One laying off 40 people(telegraph.co.uk)
2 points by crocal 8y ago|0 comments
147.
by crocal 8y ago
I would recommend getting a MS degree in /systems/ engineering. From there, you can study the distributed world but also you can access the equally fascinating world of general systems engineering. To make it better, your computer
148.
by crocal 8y ago
Also mentionned in Legend of Galactic Heroes by Yoshiki Tanaka. The founder of the Free Planet Alliances escape from its prison world by using ice asteroids as vessels for interstellar travel.
149.
by crocal 8y ago
A synchronous language models everything as a mathematical function that is completely evaluated every « tick » of a clock (hence the term synchronous). It is very convenient for real time software: the resulting executable code is a single
150.
by crocal 8y ago
Out of this language was spined off an entire company (Esterel technologies). They developed the SCADE suite and it was/is used to develop safety critical software in various industries (aeronautics, railways, nuke...) [1]. There are c

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