GE Therac. That is used as an example in many programming classes. It is legendary. Or at least it was when I was in college. I happened when I was an undergrad.
As I recall, it was a race condition. The operators got so good that they were entering key stroke sequences faster than the machine could process them. It locked open an aperture that controlled the dose. So folks got the max dose, even when the operator thought the machine was off. https://en.wikipedia.org/wiki/Therac-25 From: Ken Hohhof Sent: Saturday, May 30, 2020 3:55 PM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] OT Doug and Bob's Excellent Adventure - 2nd Try Exactly. We are so used to software products where you can fail fast and learn without killing people. I remember my college roommate went to work for a big X-ray equipment company like GE or Siemens. They had a firmware bug where a therapeutic (as opposed to diagnostic) X-ray system delivered something like 10 times the correct dose, and killed a patient. The manufacturer sent a team and couldn’t find a defect, decided it must have been human error, until it killed another patient. Oops, just a minor coding error. From: AF <af-boun...@af.afmug.com> On Behalf Of Matt Hoppes Sent: Saturday, May 30, 2020 4:13 PM To: AnimalFarm Microwave Users Group <af@af.afmug.com> Subject: Re: [AFMUG] OT Doug and Bob's Excellent Adventure - 2nd Try As long as they do that before people are on top. On May 30, 2020, at 4:49 PM, Bill Prince <part15...@gmail.com> wrote: I imagine they instrument the *)&%%$ out of it and have 10 (or so) super-slow-mo cameras going at once to figure out what went wrong. bp<part15sbs{at}gmail{dot}com> On 5/30/2020 1:33 PM, Chuck McCown wrote: You learn some of the most valuable lessons from failures. They sn4 blew up. Sn5&6 are already built and ready to incorporate the changes that come out of this failure. Much quicker way to develop rockets. Make lots of them, blow up lots of them, Sent from my iPhone On May 30, 2020, at 1:58 PM, Ken Hohhof mailto:af...@kwisp.com wrote: Well, SpaceX has that Mars rocket program or whatever it is, that blew up again yesterday. I saw a video clip where the narrator said something like “that wasn’t nominal”. I’m imagining the famous film of the Hindenburg disaster where the radio announcer says “that wasn’t nominal” instead of “oh the humanity”. From: AF mailto:af-boun...@af.afmug.com On Behalf Of ch...@wbmfg.com Sent: Saturday, May 30, 2020 2:44 PM To: AnimalFarm Microwave Users Group mailto:af@af.afmug.com Subject: Re: [AFMUG] OT Doug and Bob's Excellent Adventure - 2nd Try So, my TSLA stock should be safe now... From: Bill Prince Sent: Saturday, May 30, 2020 12:53 PM To: af@af.afmug.com Subject: Re: [AFMUG] OT Doug and Bob's Excellent Adventure - 2nd Try It's not quite like shooting a bullet. There is a window that they can maneuver within. It may have to do with the amount of propellant carried in the "garage" attached to the back of the crew dragon. There also has to be enough left in that to de-orbit. I saw a series of diagrams somewhere (maybe on the SpaceX web site?) that illustrated all the various maneuvers at the different stages. The approach to the ISS is interesting in that there is an exclusion zone of sorts all around the ISS. They need to target to outside that zone until they make their final approach. Once they are in a parallel orbit just outside the exclusion zone, they can rotate and maneuver into the docking station. The crew dragon (and the cargo dragon) is that the whole operation is autonomous. bp<part15sbs{at}gmail{dot}com> On 5/30/2020 11:39 AM, Ken Hohhof wrote: Guy on radio was saying SpaceX crew capsule has to be launched at a specific time to rendezvous with the ISS, sounds like shooting a bullet. Same guy said Boeing design will have a wider launch window because it is more maneuverable. Looking at photos they don’t seem that different. Does this sound right? Main difference seems to be the way they land, in water or on land. Not sure what happens to Boeing capsule if collapse of air travel on top of 737 Max fiasco spells the end of Boeing as a company. From: AF mailto:af-boun...@af.afmug.com On Behalf Of Bill Prince Sent: Saturday, May 30, 2020 1:25 PM To: af@af.afmug.com Subject: Re: [AFMUG] OT Doug and Bob's Excellent Adventure - 2nd Try 1522 EDT (AKA 3:22 PM) 1422 CDT (AKA 2:22 PM) 1322 MDT (AKA 1:22 PM) 1222 PDT (AKA 12:22 PM) If you're not on daylight saving time, you know what to do. bp<part15sbs{at}gmail{dot}com> On 5/30/2020 11:18 AM, ch...@wbmfg.com wrote: Just a reminder in case you forgot. -------------------------------------------------------------------------- -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -------------------------------------------------------------------------------- -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
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