* F-22 Raptor software problem @ 2007-02-26 4:47 Hyman Rosen 2007-02-26 8:55 ` Alex R. Mosteo 2007-02-26 23:55 ` peter koch 0 siblings, 2 replies; 19+ messages in thread From: Hyman Rosen @ 2007-02-26 4:47 UTC (permalink / raw) It's being reported (Slashdot, via CNN) that twelve of these planes had their navigation and communications completely shut down as they crossed the international date line while flying from Hawaii to Japan. I believe much of the plane's software is in Ada, but I have no details as to what caused the error. ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-26 4:47 F-22 Raptor software problem Hyman Rosen @ 2007-02-26 8:55 ` Alex R. Mosteo 2007-02-26 15:01 ` Aurele 2007-02-26 23:55 ` peter koch 1 sibling, 1 reply; 19+ messages in thread From: Alex R. Mosteo @ 2007-02-26 8:55 UTC (permalink / raw) Hyman Rosen wrote: > It's being reported (Slashdot, via CNN) that twelve of these > planes had their navigation and communications completely shut > down as they crossed the international date line while flying > from Hawaii to Japan. I believe much of the plane's software > is in Ada, but I have no details as to what caused the error. Linky to slashdot: http://it.slashdot.org/article.pl?sid=07/02/25/2038217 "The new US stealth fighter, the F-22 Raptor, was deployed for the first time to Asia earlier this month. On Feb. 11, twelve Raptors flying from Hawaii to Japan were forced to turn back when a software glitch crashed all of the F-22s' on-board computers as they crossed the international date line. The delay in arrival in Japan was previously reported, with rumors of problems with the software. CNN television, however, this morning reported that every fighter completely lost all navigation and communications when they crossed the international date line. They reportedly had to turn around and follow their tankers by visual contact back to Hawaii. According to the CNN story, if they had not been with their tankers, or the weather had been bad, this would have been serious. CNN has not put up anything on their website yet." The summary is, they say in the comments, incorrect, since the F22 relies in computers for control so a crash of "all on-board computers" would have been quite a bigger problem. ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-26 8:55 ` Alex R. Mosteo @ 2007-02-26 15:01 ` Aurele 2007-02-26 20:57 ` Simon Wright ` (3 more replies) 0 siblings, 4 replies; 19+ messages in thread From: Aurele @ 2007-02-26 15:01 UTC (permalink / raw) On Feb 26, 3:55 am, "Alex R. Mosteo" <devn...@mailinator.com> wrote: > Hyman Rosen wrote: > > It's being reported (Slashdot, via CNN) that twelve of these > > planes had their navigation and communications completely shut > > down as they crossed the international date line while flying > > from Hawaii to Japan. I believe much of the plane's software > > is in Ada, but I have no details as to what caused the error. > > Linky to slashdot: > > http://it.slashdot.org/article.pl?sid=07/02/25/2038217 > > "The new US stealth fighter, the F-22 Raptor, was deployed for the first time > to Asia earlier this month. On Feb. 11, twelve Raptors flying from Hawaii to > Japan were forced to turn back when a software glitch crashed all of the > F-22s' on-board computers as they crossed the international date line. The > delay in arrival in Japan was previously reported, with rumors of problems > with the software. CNN television, however, this morning reported that every > fighter completely lost all navigation and communications when they crossed > the international date line. They reportedly had to turn around and follow > their tankers by visual contact back to Hawaii. According to the CNN story, if > they had not been with their tankers, or the weather had been bad, this would > have been serious. CNN has not put up anything on their website yet." > > The summary is, they say in the comments, incorrect, since the F22 relies in > computers for control so a crash of "all on-board computers" would have been > quite a bigger problem. Well, someone is likely to lose their job for improperly implementing the geoid and/or datum model! ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-26 15:01 ` Aurele @ 2007-02-26 20:57 ` Simon Wright 2007-02-26 22:08 ` JPWoodruff ` (2 subsequent siblings) 3 siblings, 0 replies; 19+ messages in thread From: Simon Wright @ 2007-02-26 20:57 UTC (permalink / raw) "Aurele" <aurele.vitali@gmail.com> writes: > Well, someone is likely to lose their job for improperly > implementing the geoid and/or datum model! Or perhaps for not ensuring that the test cases covered this possibility. I have to say I'm not sure I would have thought of that one! ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-26 15:01 ` Aurele 2007-02-26 20:57 ` Simon Wright @ 2007-02-26 22:08 ` JPWoodruff 2007-02-27 0:15 ` Jeffrey Creem 2007-02-27 14:33 ` Bob Spooner 3 siblings, 0 replies; 19+ messages in thread From: JPWoodruff @ 2007-02-26 22:08 UTC (permalink / raw) On Feb 26, 7:01 am, "Aurele" <aurele.vit...@gmail.com> wrote: > On Feb 26, 3:55 am, "Alex R. Mosteo" <devn...@mailinator.com> wrote: > > > > > Hyman Rosen wrote: > > > It's being reported (Slashdot, via CNN) that twelve of these > > > planes had their navigation and communications completely shut > > > down as they crossed the international date line while flying > > > from Hawaii to Japan. I believe much of the plane's software > > > is in Ada, but I have no details as to what caused the error. > > > Linky to slashdot: > > >http://it.slashdot.org/article.pl?sid=07/02/25/2038217 > > > "The new US stealth fighter, the F-22 Raptor, was deployed for the first time > > to Asia earlier this month. On Feb. 11, twelve Raptors flying from Hawaii to > > Japan were forced to turn back when a software glitch crashed all of the > > F-22s' on-board computers as they crossed the international date line. The > > delay in arrival in Japan was previously reported, with rumors of problems > > with the software. CNN television, however, this morning reported that every > > fighter completely lost all navigation and communications when they crossed > > the international date line. They reportedly had to turn around and follow > > their tankers by visual contact back to Hawaii. According to the CNN story, if > > they had not been with their tankers, or the weather had been bad, this would > > have been serious. CNN has not put up anything on their website yet." > > > The summary is, they say in the comments, incorrect, since the F22 relies in > > computers for control so a crash of "all on-board computers" would have been > > quite a bigger problem. > > Well, someone is likely to lose their job for improperly implementing > the geoid and/or datum model! I don't think fault will fall so harshly on the implementer. But the members of the configuration control committee have some explaining to do. ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-26 15:01 ` Aurele 2007-02-26 20:57 ` Simon Wright 2007-02-26 22:08 ` JPWoodruff @ 2007-02-27 0:15 ` Jeffrey Creem 2007-02-27 14:33 ` Bob Spooner 3 siblings, 0 replies; 19+ messages in thread From: Jeffrey Creem @ 2007-02-27 0:15 UTC (permalink / raw) Aurele wrote: > Well, someone is likely to lose their job for improperly implementing > the geoid and/or datum model! > Given the age of the F-22 software, the person that wrote it is probably retired by now. Either way, people rarely loose their jobs for such things. ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-26 15:01 ` Aurele ` (2 preceding siblings ...) 2007-02-27 0:15 ` Jeffrey Creem @ 2007-02-27 14:33 ` Bob Spooner 2007-02-28 4:05 ` Aurele 2007-02-28 5:09 ` JPWoodruff 3 siblings, 2 replies; 19+ messages in thread From: Bob Spooner @ 2007-02-27 14:33 UTC (permalink / raw) "Aurele" <aurele.vitali@gmail.com> wrote in message news:1172502110.098416.297700@q2g2000cwa.googlegroups.com... > On Feb 26, 3:55 am, "Alex R. Mosteo" <devn...@mailinator.com> wrote: > > Well, someone is likely to lose their job for improperly implementing > the geoid and/or datum model! > I would be inclined to think that the (derived) requirements were incompletely specified and therefore didn't cover the case of what happens when the nav system, while using GPS signals for time, crosses the date line (or something like that.) -- Bob ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-27 14:33 ` Bob Spooner @ 2007-02-28 4:05 ` Aurele 2007-02-28 15:47 ` Bob Spooner 2007-02-28 5:09 ` JPWoodruff 1 sibling, 1 reply; 19+ messages in thread From: Aurele @ 2007-02-28 4:05 UTC (permalink / raw) On Feb 27, 9:33 am, "Bob Spooner" <r...@psu.edu> wrote: > "Aurele" <aurele.vit...@gmail.com> wrote in message > > news:1172502110.098416.297700@q2g2000cwa.googlegroups.com...> On Feb 26, 3:55 am, "Alex R. Mosteo" <devn...@mailinator.com> wrote: > > > Well, someone is likely to lose their job for improperly implementing > > the geoid and/or datum model! > > I would be inclined to think that the (derived) requirements were > incompletely specified and therefore didn't cover the case of what happens > when the nav system, while using GPS signals for time, crosses the date line > (or something like that.) -- Bob I'm sure its not a drived requirement. The international date line has been there forever! Also, time is always measured wrt Greenwich time in England. So, not a big deal. As Simon above said, it is probably just a test case that fell through the cracks! Go to http://wwp.greenwichmeantime.com/info/timezone.htm for more info on Time Zones. p.s. "or something like that" has very little meaning! :-) ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-28 4:05 ` Aurele @ 2007-02-28 15:47 ` Bob Spooner 0 siblings, 0 replies; 19+ messages in thread From: Bob Spooner @ 2007-02-28 15:47 UTC (permalink / raw) "Aurele" <aurele.vitali@gmail.com> wrote in message news:1172635528.435013.151190@m58g2000cwm.googlegroups.com... > On Feb 27, 9:33 am, "Bob Spooner" <r...@psu.edu> wrote: >> "Aurele" <aurele.vit...@gmail.com> wrote in message >> >> news:1172502110.098416.297700@q2g2000cwa.googlegroups.com...> On Feb 26, >> 3:55 am, "Alex R. Mosteo" <devn...@mailinator.com> wrote: >> >> > Well, someone is likely to lose their job for improperly implementing >> > the geoid and/or datum model! >> >> I would be inclined to think that the (derived) requirements were >> incompletely specified and therefore didn't cover the case of what >> happens >> when the nav system, while using GPS signals for time, crosses the date >> line >> (or something like that.) -- Bob > > I'm sure its not a drived requirement. The international date line has > been there forever! Also, time is always measured wrt Greenwich time > in England. So, not a big deal. As Simon above said, it is probably > just a test case that fell through the cracks! Go to > http://wwp.greenwichmeantime.com/info/timezone.htm for more info on > Time Zones. > > p.s. "or something like that" has very little meaning! :-) > Well, the reason I think that it is a derived requirement is because if it were explicit in the contract, there would have to be traceability to both the code implementation and to the test that verified that it was implemented correctly. Bob ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-27 14:33 ` Bob Spooner 2007-02-28 4:05 ` Aurele @ 2007-02-28 5:09 ` JPWoodruff 1 sibling, 0 replies; 19+ messages in thread From: JPWoodruff @ 2007-02-28 5:09 UTC (permalink / raw) On Feb 27, 6:33 am, "Bob Spooner" <r...@psu.edu> wrote: > "Aurele" <aurele.vit...@gmail.com> wrote in message > > news:1172502110.098416.297700@q2g2000cwa.googlegroups.com...> On Feb 26, 3:55 am, "Alex R. Mosteo" <devn...@mailinator.com> wrote: > > > Well, someone is likely to lose their job for improperly implementing > > the geoid and/or datum model! > > I would be inclined to think that the (derived) requirements were > incompletely specified and therefore didn't cover the case of what happens > when the nav system, while using GPS signals for time, crosses the date line > (or something like that.) -- Bob Something's bothering me about this case, and hasn't been mentioned yet. I think I'm correct in guessing that this aircraft has been in service for some time. If that's true, then almost certainly some F-22 has crossed the dateline without difficulty in the past. So it's a change in the software that started the failure. My own experience taught me it's difficult to assure integrity as a large system evolves. The system needs an effective configuration control board, and that team needs a really sound process. This is easier said than done. We can hope that practical "lessons learned" will be shared when this case has been analyzed. ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-26 4:47 F-22 Raptor software problem Hyman Rosen 2007-02-26 8:55 ` Alex R. Mosteo @ 2007-02-26 23:55 ` peter koch 2007-02-27 0:22 ` Gene 2007-02-28 7:44 ` Keith Thompson 1 sibling, 2 replies; 19+ messages in thread From: peter koch @ 2007-02-26 23:55 UTC (permalink / raw) On 26 Feb., 05:47, Hyman Rosen <hyro...@mail.com> wrote: > It's being reported (Slashdot, via CNN) that twelve of these > planes had their navigation and communications completely shut > down as they crossed the international date line while flying > from Hawaii to Japan. I believe much of the plane's software > is in Ada, but I have no details as to what caused the error. It surprises me that the software had problems dealing with this problem in the first place. Why anyone uses "calender time" for anything but display purposes is simply beyond my comprehension. /Peter ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-26 23:55 ` peter koch @ 2007-02-27 0:22 ` Gene 2007-02-28 7:44 ` Keith Thompson 1 sibling, 0 replies; 19+ messages in thread From: Gene @ 2007-02-27 0:22 UTC (permalink / raw) On Feb 26, 6:55 pm, "peter koch" <peter.koch.lar...@gmail.com> wrote: > On 26 Feb., 05:47, Hyman Rosen <hyro...@mail.com> wrote: > > > It's being reported (Slashdot, via CNN) that twelve of these > > planes had their navigation and communications completely shut > > down as they crossed the international date line while flying > > from Hawaii to Japan. I believe much of the plane's software > > is in Ada, but I have no details as to what caused the error. > > It surprises me that the software had problems dealing with this > problem in the first place. Why anyone uses "calender time" for > anything but display purposes is simply beyond my comprehension. > > /Peter I vaguely remember years ago reading that the original F-16 flight control software flipped the plane inverted when flown into the southern hemisphere. However, this was caught in a simulator before the software was ever flown. History repeats itself (sort of...). ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-26 23:55 ` peter koch 2007-02-27 0:22 ` Gene @ 2007-02-28 7:44 ` Keith Thompson 2007-02-28 12:33 ` peter koch 2007-02-28 20:22 ` Keith Thompson 1 sibling, 2 replies; 19+ messages in thread From: Keith Thompson @ 2007-02-28 7:44 UTC (permalink / raw) "peter koch" <peter.koch.larsen@gmail.com> writes: > On 26 Feb., 05:47, Hyman Rosen <hyro...@mail.com> wrote: >> It's being reported (Slashdot, via CNN) that twelve of these >> planes had their navigation and communications completely shut >> down as they crossed the international date line while flying >> from Hawaii to Japan. I believe much of the plane's software >> is in Ada, but I have no details as to what caused the error. > > It surprises me that the software had problems dealing with this > problem in the first place. Why anyone uses "calender time" for > anything but display purposes is simply beyond my comprehension. I'm only guessing, but I doubt that the error was caused by using local time. My suspicion is that the error occurred not when crossing the International Date Line (which is crooked, as you can see on a map), but when crossing the 180th meridian, when the longitude jumped from 179.909 to -179.990. I vaguely remember a similar problem with some air traffic control software that was developed in the US, but wouldn't work in the UK, because it couldn't handle a sign change in longitude. -- Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst> San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst> "We must do something. This is something. Therefore, we must do this." -- Antony Jay and Jonathan Lynn, "Yes Minister" ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-28 7:44 ` Keith Thompson @ 2007-02-28 12:33 ` peter koch 2007-02-28 15:51 ` Bob Spooner 2007-02-28 19:49 ` Simon Wright 2007-02-28 20:22 ` Keith Thompson 1 sibling, 2 replies; 19+ messages in thread From: peter koch @ 2007-02-28 12:33 UTC (permalink / raw) On Feb 28, 8:44 am, Keith Thompson <k...@mib.org> wrote: > "peter koch" <peter.koch.lar...@gmail.com> writes: > > On 26 Feb., 05:47, Hyman Rosen <hyro...@mail.com> wrote: > >> It's being reported (Slashdot, via CNN) that twelve of these > >> planes had their navigation and communications completely shut > >> down as they crossed the international date line while flying > >> from Hawaii to Japan. I believe much of the plane's software > >> is in Ada, but I have no details as to what caused the error. > > > It surprises me that the software had problems dealing with this > > problem in the first place. Why anyone uses "calender time" for > > anything but display purposes is simply beyond my comprehension. > > I'm only guessing, but I doubt that the error was caused by using > local time. My suspicion is that the error occurred not when crossing > the International Date Line (which is crooked, as you can see on a > map), but when crossing the 180th meridian, when the longitude jumped > from 179.909 to -179.990. > > I vaguely remember a similar problem with some air traffic control > software that was developed in the US, but wouldn't work in the UK, > because it couldn't handle a sign change in longitude. > Yes - that makes far more sense. I had a very difficult time (!) believe that the problem had anything to do with timezones. /Peter ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-28 12:33 ` peter koch @ 2007-02-28 15:51 ` Bob Spooner 2007-02-28 16:15 ` Markus E Leypold 2007-02-28 19:49 ` Simon Wright 1 sibling, 1 reply; 19+ messages in thread From: Bob Spooner @ 2007-02-28 15:51 UTC (permalink / raw) "peter koch" <peter.koch.larsen@gmail.com> wrote in message news:1172666017.141406.173400@v33g2000cwv.googlegroups.com... > On Feb 28, 8:44 am, Keith Thompson <k...@mib.org> wrote: >> "peter koch" <peter.koch.lar...@gmail.com> writes: >> > On 26 Feb., 05:47, Hyman Rosen <hyro...@mail.com> wrote: >> >> It's being reported (Slashdot, via CNN) that twelve of these >> >> planes had their navigation and communications completely shut >> >> down as they crossed the international date line while flying >> >> from Hawaii to Japan. I believe much of the plane's software >> >> is in Ada, but I have no details as to what caused the error. >> >> > It surprises me that the software had problems dealing with this >> > problem in the first place. Why anyone uses "calender time" for >> > anything but display purposes is simply beyond my comprehension. >> >> I'm only guessing, but I doubt that the error was caused by using >> local time. My suspicion is that the error occurred not when crossing >> the International Date Line (which is crooked, as you can see on a >> map), but when crossing the 180th meridian, when the longitude jumped >> from 179.909 to -179.990. >> >> I vaguely remember a similar problem with some air traffic control >> software that was developed in the US, but wouldn't work in the UK, >> because it couldn't handle a sign change in longitude. >> > Yes - that makes far more sense. I had a very difficult time (!) > believe that the problem had anything to do with timezones. > > /Peter > If the navigation computer was calculating velocity as a change in position with respect to time and the time changed by a large (possibly negative) amount, something could have gotten out of range and caused a software crash. Bob ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-28 15:51 ` Bob Spooner @ 2007-02-28 16:15 ` Markus E Leypold 0 siblings, 0 replies; 19+ messages in thread From: Markus E Leypold @ 2007-02-28 16:15 UTC (permalink / raw) "Bob Spooner" <rls19@psu.edu> writes: > "peter koch" <peter.koch.larsen@gmail.com> wrote in message > news:1172666017.141406.173400@v33g2000cwv.googlegroups.com... >> On Feb 28, 8:44 am, Keith Thompson <k...@mib.org> wrote: >>> "peter koch" <peter.koch.lar...@gmail.com> writes: >>> > On 26 Feb., 05:47, Hyman Rosen <hyro...@mail.com> wrote: >>> >> It's being reported (Slashdot, via CNN) that twelve of these >>> >> planes had their navigation and communications completely shut >>> >> down as they crossed the international date line while flying >>> >> from Hawaii to Japan. I believe much of the plane's software >>> >> is in Ada, but I have no details as to what caused the error. >>> >>> > It surprises me that the software had problems dealing with this >>> > problem in the first place. Why anyone uses "calender time" for >>> > anything but display purposes is simply beyond my comprehension. >>> >>> I'm only guessing, but I doubt that the error was caused by using >>> local time. My suspicion is that the error occurred not when crossing >>> the International Date Line (which is crooked, as you can see on a >>> map), but when crossing the 180th meridian, when the longitude jumped >>> from 179.909 to -179.990. >>> >>> I vaguely remember a similar problem with some air traffic control >>> software that was developed in the US, but wouldn't work in the UK, >>> because it couldn't handle a sign change in longitude. >>> >> Yes - that makes far more sense. I had a very difficult time (!) >> believe that the problem had anything to do with timezones. >> >> /Peter >> > If the navigation computer was calculating velocity as a change in position > with respect to time and the time changed by a large (possibly negative) > amount, something could have gotten out of range and caused a software > crash. Bob On would think that internal time keeping would always done in GMT or with a counter with a fixed offset to GMT, esp. since GPS works with GMT anyway. Regards -- Markus ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-28 12:33 ` peter koch 2007-02-28 15:51 ` Bob Spooner @ 2007-02-28 19:49 ` Simon Wright 2007-02-28 20:31 ` Keith Thompson 1 sibling, 1 reply; 19+ messages in thread From: Simon Wright @ 2007-02-28 19:49 UTC (permalink / raw) "peter koch" <peter.koch.larsen@gmail.com> writes: > On Feb 28, 8:44 am, Keith Thompson <k...@mib.org> wrote: >> I'm only guessing, but I doubt that the error was caused by using >> local time. My suspicion is that the error occurred not when >> crossing the International Date Line (which is crooked, as you can >> see on a map), but when crossing the 180th meridian, when the >> longitude jumped from 179.909 to -179.990. > Yes - that makes far more sense. I had a very difficult time (!) > believe that the problem had anything to do with timezones. I could believe it if there were requirements to do something say every quarter-hour on the quarter-hour in local time. What seems hard to imagine in a military aircraft is the 'local time' part! ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-28 19:49 ` Simon Wright @ 2007-02-28 20:31 ` Keith Thompson 0 siblings, 0 replies; 19+ messages in thread From: Keith Thompson @ 2007-02-28 20:31 UTC (permalink / raw) Simon Wright <simon.j.wright@mac.com> writes: > "peter koch" <peter.koch.larsen@gmail.com> writes: >> On Feb 28, 8:44 am, Keith Thompson <k...@mib.org> wrote: >>> I'm only guessing, but I doubt that the error was caused by using >>> local time. My suspicion is that the error occurred not when >>> crossing the International Date Line (which is crooked, as you can >>> see on a map), but when crossing the 180th meridian, when the >>> longitude jumped from 179.909 to -179.990. > >> Yes - that makes far more sense. I had a very difficult time (!) >> believe that the problem had anything to do with timezones. > > I could believe it if there were requirements to do something say > every quarter-hour on the quarter-hour in local time. What seems hard > to imagine in a military aircraft is the 'local time' part! It would be easier to do something every quarter-hour in UTC; it will be done at the sames, even in places with half-hour time zones. And an F-22 at top speed can cross a time zone in a few minutes. Performing tasks that depend on local time wouldn't make much sense; performing such tasks in a critical subsystem (which is what crashed) makes even less sense. -- Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst> San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst> "We must do something. This is something. Therefore, we must do this." -- Antony Jay and Jonathan Lynn, "Yes Minister" ^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: F-22 Raptor software problem 2007-02-28 7:44 ` Keith Thompson 2007-02-28 12:33 ` peter koch @ 2007-02-28 20:22 ` Keith Thompson 1 sibling, 0 replies; 19+ messages in thread From: Keith Thompson @ 2007-02-28 20:22 UTC (permalink / raw) Keith Thompson <kst-u@mib.org> writes: [...] > I'm only guessing, but I doubt that the error was caused by using > local time. My suspicion is that the error occurred not when crossing > the International Date Line (which is crooked, as you can see on a > map), but when crossing the 180th meridian, when the longitude jumped > from 179.909 to -179.990. Sorry about the random-seeming numbers. I meant "from 179.999 to -179.999". (I originally used two decimal places, then decided to add a third, and typed '0' instead of '9'.) I *will* proofread this before sending it! -- Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst> San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst> "We must do something. This is something. Therefore, we must do this." -- Antony Jay and Jonathan Lynn, "Yes Minister" ^ permalink raw reply [flat|nested] 19+ messages in thread
end of thread, other threads:[~2007-02-28 20:31 UTC | newest] Thread overview: 19+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2007-02-26 4:47 F-22 Raptor software problem Hyman Rosen 2007-02-26 8:55 ` Alex R. Mosteo 2007-02-26 15:01 ` Aurele 2007-02-26 20:57 ` Simon Wright 2007-02-26 22:08 ` JPWoodruff 2007-02-27 0:15 ` Jeffrey Creem 2007-02-27 14:33 ` Bob Spooner 2007-02-28 4:05 ` Aurele 2007-02-28 15:47 ` Bob Spooner 2007-02-28 5:09 ` JPWoodruff 2007-02-26 23:55 ` peter koch 2007-02-27 0:22 ` Gene 2007-02-28 7:44 ` Keith Thompson 2007-02-28 12:33 ` peter koch 2007-02-28 15:51 ` Bob Spooner 2007-02-28 16:15 ` Markus E Leypold 2007-02-28 19:49 ` Simon Wright 2007-02-28 20:31 ` Keith Thompson 2007-02-28 20:22 ` Keith Thompson
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