I worked on the B-2 Bomber's Flight Control System. We had a "stick shaker" wired to the pilot's controls that would vbrate when a stall condition was detected. This was activated after a warning light and tone were already used to alert the pilot. I have no experience with any other flight control system, but I would suspect that this is not unique to the B-2.
Perhaps another slashdotter can post and let us know.
I remember a comic a few years ago when Hollywood put out all those giant-space-rock-hits-the-earth movies like Deep Impact. In the comic, a couple is standing in front of a giant, garish "Planet Hollywood" restaurant. The man shakes his head sadly and comments:
"Where's a giant flaming meteor when you need one?"
A well thought out interrupt design is straightforward. I worked on the flight control system for the B-2 bomber. We used interrupts and backed them up with a solid design (quad redundancy, amongst other things) and lots of testing. I know that we inherited the basic software from another plane (F-15?), so that makes at least one other flight control system that used interrupts. I believe that there are other fly by wire systems (both military and civilian) that use interrupts and I know of many other avionics systems that use them, too.
Here are systems where failure means the plane would have crashed (rumor had it that wind tunnel testing of the B-2 showed it would actually disintegrate in flight on a flight control lockup, but that's just hearsay) and other mission critical systems, but yet they all use interrupts. Why is that? Interrupts can indeed be risky, but proper understanding of what they are and how to design and test them mitigate those risks. To make a blanket statement of "Interrupts = bad" is akin to saying "High level languages = bad" or even "ADA = self documenting = all ADA code good, even without dcouments".
Frankly, I'd be more concerned about a piece of software that tries to enforce a sequential polling architecture on the complex, chaotic series of events known as "real time" than a system that takes advantage of the built in hardware hardware features (interrupts) to make a simpler, event driven architecture.
When I was 19, I landed a job working as a waiter on Amtrak (America's nationalized passenger railroad, in case you're overseas) as a Summer job. It was a good job with more money and benefits than anything I'd done before. Since railroad work has a history of being somewhat dangerous, the job came with automatic life insurance. Something like $10K from the railroad and $75K from the union. This was at a time when my family's home in suburban Los Angeles was assessed at about $80K (1988).
One day between trips, I had a bunch of buddies come over to the house and help me fix a fence. They got to joking with my Mom about her being the beneficiary of the policy and how horrible it would be if I had an "accident." Did my mother, the woman who brought into this world, defend me from these homicidal overtures of my so called "friends"?
No. She started to take bids to see which one of them could do it cheaper.
you're not the kind of person that either side wants on the jury
Actually, if you play the "engineer card" right, only one side wants you off. If you state that you'll use the rules the judge lays down and apply them in a logical, impartial manner, the side with the stonger case will be drooling at the mouth, desperate to have you on the jury. The side with the weaker argument, though, will thank you for your time and send you on your way. While this should work with anyone who expresses this belief (which, of course, is exactly what you're supposed to do), the perception of engineers by the public adds weight.
Naturally, if it's a close call and both sides think they have a strong case, this will backfire. No problem to me - I'm willing to do my civic duty. This was also the case with my coworker.
What irked me in the whole instance was my manager's belief that his project was the most important thing in the universe, more important than our families or civic duty. It steamed me that "getting out" of jury duty was preferable to simply stating the facts about your profession and seeing if you're rejected as a matter of course. This was at a company that was always priding itself on being a good corporate citizen.
I had a lot of good times at that job, but thinking about this one instance makes me want to go and take a shower to get clean again.
Can't use pointers in C++ code, because the manager doesn't understand them
Have a similar, second hand story. I had a coworker who worked on power supply units for submarines, circa 1998. They had some incident happen where a computer crashed - I don't know if it was a test stand or at sea. It was serious, though, and the fecal matter hit the rotational ventilation unit. The Navy ripped the project apart, demanding answers. So far, so good - rational customer behavior.
It turned out that the fault was a bad ISR that got hung up. The techies tried to explain what had happened and how to fix it, but they apparently did a very poor job. Instead of demanding stricter coding standards, reviews, or the like, the admiral involved got completely freaked out by the notion of an ISR. He'd never heard of such a beast and the idea that a computer could interrupt its normal processing and then return was incredibly risky and blasphemous (never mind that it is possible to formally prove that your ISR can and will return).
The Admiral's judgement: "There will be none of these ISR things on my boat!" Crazy, but he was the Admiral.
Imagine: You're coding dozens of embedded systems on a submarine and you can't use interrupts! The entire power supply was recoded to use a polling architecture, monitoring flags in a main loop and then servicing them instead of letting an interrupt run to do it.
Wasn't an active member of the bar or serving a counsel, though. A shame, as I'm sure we could have done something if he was an "officer of the court" encouraging perjury.
Apologies for sticking my nose into this, but I really have to wonder why your app (or perhaps some intermediate add on utility you could have written) couldn't open a text or RTF file? You could have had your interns save the Word document that way (perhaps use a Word macro to automate the process) and then your app could grab and process the file.
This is pretty obvious, so I'm sure you must have thought of this. I'm just curious why you couldn't have done it.
The job I recently left was one of those doomed projects that drive managers to the brink. My manager, a six foot eight guy who was big on physical intimidation, had been given a task that should have been staffed at about twenty people. Unfortunately, he was only given eight due to politcial and resource issues. He was never big on people skills, but this project put him under incredible pressure. He did not handle it well, driving us all to do 20+ hours unpaid overtime a week in direct conflict with the current division policy (they'd reinstated paid overtime to help with employee retention problems, but we were denied it due to the project's budget). When we'd complained or attempted transfers, the manager took it personally and browbeat us. Taking vacation or even sick time was frowned upon. I was badmouthed for taking bereavement leave to support my wife when her father died.
The crowning moment, though, came when a hardware guy (father, scoutmaster, perfect citizen) had to miss a day for jury duty. That afternoon, my coworker called in and said he would have to miss a second day because he'd been picked as a possible juror on a case but they'd not gotten around to directly questioning him yet.
Our leader promptly badmouthed my coworker in front of our entire staff for not "doing what he needed to do" to "get out of it." While it was never spelled out, it was obvious he was angry that my coworker hadn't perjured himself to get off the jury.
Two days later, my coworker returned as promised. As he'd predicted, he hadn't made it through the direct questions - he's an engineer. When he heard about what had happened in his absence, I made sure that he was one of the first to critique my resume.
I think it's a shame they'll miss the better window, but giving more time to check out the on board diagnostics seems like a dang fine reason. I'd hate to see the thing get all the way to Mercury and then go dead. If the program mangers want this breathing space (and you can be sure they'd only consider this if they were getting a lot of warnings from within the ranks), they'd be fools not to take it. Still, the extra Venus flyby would have been nice (2 vs. 3).
I'm kinda concerned about the budget hit, though. Maintaining an engineering infrastructure on the ground for an additional two years, even one in "standby," is going to be costly. Sure, they can loan out personell to other projects during the interim, but you're going to see two more years of attrition and then retraining costs to catch up. A boom or bust in the tech cycle will simply agravate the situation (boom=more people leaving, bust=fewer new engineers to fill vacated slots).
The delay is probably acceptable, but let's hope the added budget doesn't hurt another probe.
I followed your link and the service looks wonderful, but I live in the Los Angeles (Orange County) area. While I've seen other traffic services online, none of them were optimized for PDAs or portable computing. Does anyone out there know services available down here that are equivilent?
(Venture capitalists take note: this would be huge in L.A.)
Money was tight for us growing up and we didn't get a color set until about I was maybe five (1973). Having not yet learned to complain and whine about being deprived of technology (it would take getting a PC to teach me that), I simply accepted that the same cartoon characters I saw at the neighbors had colors but were black and white at home. I watched a lot of TV, though, both at home and at friends' houses. Same programs, same cartoons, same commercials.
I distinctly remember one day watching the tube at home and seeing a MacDonalds commercial that I'd seen dozens of times elsewhere appear in color on our black and white TV!! Obviously, my little primate brain was responding to the cues from the commercial and filling in the bright yellows and reds on Ronald's costume for me. I ran into the kitchen to tell my Mom, but by the time I dragged her into the living room all the colors were gone.
I think we got a color TV maybe a few months after that. Maybe Mom thought it was cheaper than counseling.
Growing up in the 70's, my family was like most lower-middle clans. We had one TV in the living room and we all zombied out to it. Once it broke and it took two weeks to get the parts (remember when you repaired TVs?). With nothing to do, we did a lot of reading and played a few board games. Mostly, though, we played with the cat.
Maybe six hours a night, we'd drag string around the living room, goof around with the fether duster, throw things back and forth, etc. The beast, very aloof even for a feline, got more attention in two weeks than she probably had in the previous six months.
Exactly. Last night I read Ben Bova's Mount Olympus (in The Hard SF Renisance -- excellent read, BTW), circa 1995, about the second manned Mars mission. In it, the scientific community is just wrapping its brain around the notion of water ever being on Mars.
It's still a good story, but has been rendered mildly obsolete. That says a lot of good things about the rover missions rather than bad things about Mr. Bova's predictive powers. Occupational hazzard.
Slashdot Mirror
I worked on the B-2 Bomber's Flight Control System. We had a "stick shaker" wired to the pilot's controls that would vbrate when a stall condition was detected. This was activated after a warning light and tone were already used to alert the pilot. I have no experience with any other flight control system, but I would suspect that this is not unique to the B-2.
Perhaps another slashdotter can post and let us know.
"Where's a giant flaming meteor when you need one?"
Hoarse, masculine voice: Er, sure. Whatever.
Operator: Wonderful. Now we just need to verify your identity.
Hoarse, masculine voice: My pulse is 85 right now. BP 150 over 200. And, yes, I'm already seeing a doctor about it.
Operator: That's just fine. So, you said you wanted this line of credit made out to "Eddie's House of Hot Skin" in San Pedro, right?
Hmmmph. I may have just found a new career direction.
Er, I mean "o!"
A well thought out interrupt design is straightforward. I worked on the flight control system for the B-2 bomber. We used interrupts and backed them up with a solid design (quad redundancy, amongst other things) and lots of testing. I know that we inherited the basic software from another plane (F-15?), so that makes at least one other flight control system that used interrupts. I believe that there are other fly by wire systems (both military and civilian) that use interrupts and I know of many other avionics systems that use them, too.
Here are systems where failure means the plane would have crashed (rumor had it that wind tunnel testing of the B-2 showed it would actually disintegrate in flight on a flight control lockup, but that's just hearsay) and other mission critical systems, but yet they all use interrupts. Why is that? Interrupts can indeed be risky, but proper understanding of what they are and how to design and test them mitigate those risks. To make a blanket statement of "Interrupts = bad" is akin to saying "High level languages = bad" or even "ADA = self documenting = all ADA code good, even without dcouments".
Frankly, I'd be more concerned about a piece of software that tries to enforce a sequential polling architecture on the complex, chaotic series of events known as "real time" than a system that takes advantage of the built in hardware hardware features (interrupts) to make a simpler, event driven architecture.
When I was 19, I landed a job working as a waiter on Amtrak (America's nationalized passenger railroad, in case you're overseas) as a Summer job. It was a good job with more money and benefits than anything I'd done before. Since railroad work has a history of being somewhat dangerous, the job came with automatic life insurance. Something like $10K from the railroad and $75K from the union. This was at a time when my family's home in suburban Los Angeles was assessed at about $80K (1988).
One day between trips, I had a bunch of buddies come over to the house and help me fix a fence. They got to joking with my Mom about her being the beneficiary of the policy and how horrible it would be if I had an "accident." Did my mother, the woman who brought into this world, defend me from these homicidal overtures of my so called "friends"?
No. She started to take bids to see which one of them could do it cheaper.
What terrifies me is that you might be able to pull this off.
Let me guess. They originally sentenced her to ten years, but when she got out she went back to the judge and claimed it was twenty five. Right?
Jokes about http://Eat<any vulgarity that will trip an obscinity filter>.com in 3, 2, 1...
Actually, if you play the "engineer card" right, only one side wants you off. If you state that you'll use the rules the judge lays down and apply them in a logical, impartial manner, the side with the stonger case will be drooling at the mouth, desperate to have you on the jury. The side with the weaker argument, though, will thank you for your time and send you on your way. While this should work with anyone who expresses this belief (which, of course, is exactly what you're supposed to do), the perception of engineers by the public adds weight.
Naturally, if it's a close call and both sides think they have a strong case, this will backfire. No problem to me - I'm willing to do my civic duty. This was also the case with my coworker.
What irked me in the whole instance was my manager's belief that his project was the most important thing in the universe, more important than our families or civic duty. It steamed me that "getting out" of jury duty was preferable to simply stating the facts about your profession and seeing if you're rejected as a matter of course. This was at a company that was always priding itself on being a good corporate citizen.
I had a lot of good times at that job, but thinking about this one instance makes me want to go and take a shower to get clean again.
Thanks. I hadn't considered having to sort into individual fields. Turns the thing into a nontrivial task. Good catch.
Have a similar, second hand story. I had a coworker who worked on power supply units for submarines, circa 1998. They had some incident happen where a computer crashed - I don't know if it was a test stand or at sea. It was serious, though, and the fecal matter hit the rotational ventilation unit. The Navy ripped the project apart, demanding answers. So far, so good - rational customer behavior.
It turned out that the fault was a bad ISR that got hung up. The techies tried to explain what had happened and how to fix it, but they apparently did a very poor job. Instead of demanding stricter coding standards, reviews, or the like, the admiral involved got completely freaked out by the notion of an ISR. He'd never heard of such a beast and the idea that a computer could interrupt its normal processing and then return was incredibly risky and blasphemous (never mind that it is possible to formally prove that your ISR can and will return).
The Admiral's judgement: "There will be none of these ISR things on my boat!" Crazy, but he was the Admiral.
Imagine: You're coding dozens of embedded systems on a submarine and you can't use interrupts! The entire power supply was recoded to use a polling architecture, monitoring flags in a main loop and then servicing them instead of letting an interrupt run to do it.
Not suprisingly, my coworker soon left.
Wasn't an active member of the bar or serving a counsel, though. A shame, as I'm sure we could have done something if he was an "officer of the court" encouraging perjury.
This is pretty obvious, so I'm sure you must have thought of this. I'm just curious why you couldn't have done it.
The crowning moment, though, came when a hardware guy (father, scoutmaster, perfect citizen) had to miss a day for jury duty. That afternoon, my coworker called in and said he would have to miss a second day because he'd been picked as a possible juror on a case but they'd not gotten around to directly questioning him yet.
Our leader promptly badmouthed my coworker in front of our entire staff for not "doing what he needed to do" to "get out of it." While it was never spelled out, it was obvious he was angry that my coworker hadn't perjured himself to get off the jury.
Two days later, my coworker returned as promised. As he'd predicted, he hadn't made it through the direct questions - he's an engineer. When he heard about what had happened in his absence, I made sure that he was one of the first to critique my resume.
I'm kinda concerned about the budget hit, though. Maintaining an engineering infrastructure on the ground for an additional two years, even one in "standby," is going to be costly. Sure, they can loan out personell to other projects during the interim, but you're going to see two more years of attrition and then retraining costs to catch up. A boom or bust in the tech cycle will simply agravate the situation (boom=more people leaving, bust=fewer new engineers to fill vacated slots).
The delay is probably acceptable, but let's hope the added budget doesn't hurt another probe.
- Dragonfish Eats Lanternfish
- Lanternfish Eats Plankton
- Plankton Eats Paper
- Paper Wraps Rock
- Rock Smashes Dragonfish
Just thought everyone whould know. That is all.I wonder if I can hack NORAD, too.
Dude, are you stalking me for my past comments? (*GRIN*)
As to tinfoil hats, if you think it's ever safe to remove it, you obviously don't need it.
She was a very talented cat, but the Fonz was a bit of a stretch. Fortunately, she had Suzanne Summers' acting ability down pat.
(Venture capitalists take note: this would be huge in L.A.)
I distinctly remember one day watching the tube at home and seeing a MacDonalds commercial that I'd seen dozens of times elsewhere appear in color on our black and white TV!! Obviously, my little primate brain was responding to the cues from the commercial and filling in the bright yellows and reds on Ronald's costume for me. I ran into the kitchen to tell my Mom, but by the time I dragged her into the living room all the colors were gone.
I think we got a color TV maybe a few months after that. Maybe Mom thought it was cheaper than counseling.
Maybe six hours a night, we'd drag string around the living room, goof around with the fether duster, throw things back and forth, etc. The beast, very aloof even for a feline, got more attention in two weeks than she probably had in the previous six months.
Man, was she pissed when we got that TV back.
It's still a good story, but has been rendered mildly obsolete. That says a lot of good things about the rover missions rather than bad things about Mr. Bova's predictive powers. Occupational hazzard.
Wasn't there a dinosaur who once said something like this?