* computer language used to program Mars Lander @ 2008-07-14 11:18 jhc0033 2008-07-14 11:21 ` jacob navia ` (4 more replies) 0 siblings, 5 replies; 61+ messages in thread From: jhc0033 @ 2008-07-14 11:18 UTC (permalink / raw) Interesting article I came across on Slashdot: http://developers.slashdot.org/developers/08/07/10/213211.shtml They are using C at JPL to program Mars Lander and just about everything now! Not Ada. Anyone got an explanation? I wonder also, do they really mean C++ when they say C. In my experience, this is a frequent, although disagreeable usage. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-14 11:18 computer language used to program Mars Lander jhc0033 @ 2008-07-14 11:21 ` jacob navia 2008-07-14 21:27 ` Maciej Sobczak 2008-07-14 11:49 ` Nick Keighley ` (3 subsequent siblings) 4 siblings, 1 reply; 61+ messages in thread From: jacob navia @ 2008-07-14 11:21 UTC (permalink / raw) jhc0033@gmail.com wrote: > Interesting article I came across on Slashdot: > > http://developers.slashdot.org/developers/08/07/10/213211.shtml > > They are using C at JPL to program Mars Lander and just about > everything now! Not Ada. Anyone got an explanation? I wonder also, do > they really mean C++ when they say C. In my experience, this is a > frequent, although disagreeable usage. They do not use even memory allocation. They use a subset of C I am sure they do not use C++! -- jacob navia jacob at jacob point remcomp point fr logiciels/informatique http://www.cs.virginia.edu/~lcc-win32 ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-14 11:21 ` jacob navia @ 2008-07-14 21:27 ` Maciej Sobczak 0 siblings, 0 replies; 61+ messages in thread From: Maciej Sobczak @ 2008-07-14 21:27 UTC (permalink / raw) On 14 Lip, 13:21, jacob navia <ja...@nospam.com> wrote: > They do not use even memory allocation. They use a subset of C > > I am sure they do not use C++! Why? I would expect some parts of C++ being used, no matter how much constrained is the target environment. In particular, C++ has better and more expressive type system, destructors that can ensure proper execution of "exit" actions, better support for encapsulation, etc. All these are real advantages as far as safe and secure code is concerned and none of these require additional run-time resources. For example, would you like to have custom integer types with range checking in this critical software? (Expected answer on this group is "yes".) This is trivial in C++ and almost impossible in C. This alone is already a reason to prefer C++ over C for such systems. Now, why there is no Ada on Mars is another story - but don't worry about what Martians will think: they will not see the source code anyway. ;-) -- Maciej Sobczak * www.msobczak.com * www.inspirel.com ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-14 11:18 computer language used to program Mars Lander jhc0033 2008-07-14 11:21 ` jacob navia @ 2008-07-14 11:49 ` Nick Keighley 2008-07-15 7:27 ` Maciej Sobczak ` (2 more replies) 2008-07-14 15:31 ` george.priv ` (2 subsequent siblings) 4 siblings, 3 replies; 61+ messages in thread From: Nick Keighley @ 2008-07-14 11:49 UTC (permalink / raw) On 14 Jul, 12:18, "jhc0...@gmail.com" <jhc0...@gmail.com> wrote: > Interesting article I came across on Slashdot: > > http://developers.slashdot.org/developers/08/07/10/213211.shtml > > They are using C at JPL to program Mars Lander and just about > everything now! Not Ada. Anyone got an explanation? I wonder also, do > they really mean C++ when they say C. In my experience, this is a > frequent, although disagreeable usage. contrary to popular expectations space probes are very conservative in their use of technolgy. Processors are old (and hence proven) memorys are small (less vulnerable to radiation). Rememeber if there's a bug they can't just upgrade the software. Well they can but it has to be mostly working for the download to work. These are essetially embedded systems and C is still popular in that world. I suspect its a damn sight easier to prove C correct than C++. a = b + c; probably does what it says in C (assuming b and c have good values and it doesn't overflow). In C++ there could be half a dozen overloaded operators in there. -- Nick Keighley I know not what I appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell, whilest the great ocean of truth lay all undiscovered before me. (Sir Issac Newton) ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-14 11:49 ` Nick Keighley @ 2008-07-15 7:27 ` Maciej Sobczak 2008-07-16 6:02 ` jhc0033 2008-07-17 21:56 ` Paul Hsieh 2 siblings, 0 replies; 61+ messages in thread From: Maciej Sobczak @ 2008-07-15 7:27 UTC (permalink / raw) On 14 Lip, 13:49, Nick Keighley <nick_keighley_nos...@hotmail.com> wrote: > I suspect its a damn sight easier to prove C correct than C++. > > a = b + c; > > probably does what it says in C (assuming b and c have good values > and it doesn't overflow). In C++ there could be half a dozen > overloaded > operators in there. Your reasoning is completely broken. Let's try this one: I suspect its a damn sight easier to prove C correct than Ada. a = b + c; probably does what it says in C. In Ada (substitute := for = ) there could be half a dozen overloaded operators in there (and some controlled operations as well). Do you think that there are some monkeys in the project that randomly overload operators? If yes, then Ada is equally vulnerable. Another point: the operator + in C *is* overloaded and not only its meaning, but also the generated object code differs depending on the types of a and b. Yes, this is what overloading is all about and yes, you can have serious errors in C because of that, especially when combined with implicit conversions. What C++ or Ada can offer in this area is at least to get rid of those implicit conversions. This is a huge gain for proving correctness of the code. -- Maciej Sobczak * www.msobczak.com * www.inspirel.com ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-14 11:49 ` Nick Keighley 2008-07-15 7:27 ` Maciej Sobczak @ 2008-07-16 6:02 ` jhc0033 2008-07-16 21:57 ` Brian 2008-07-23 14:43 ` Michael Oswald 2008-07-17 21:56 ` Paul Hsieh 2 siblings, 2 replies; 61+ messages in thread From: jhc0033 @ 2008-07-16 6:02 UTC (permalink / raw) On Jul 14, 4:49 am, Nick Keighley <nick_keighley_nos...@hotmail.com> wrote: > contrary to popular expectations space probes are very > conservative in their use of technolgy. I disagree. Actually, the space industry will try anything and stick with it until stuff explodes (Ariane rocket) or crashes into the wrong celestial body because of faulty software. They did use Ada widely before, and they even programmed some of their probes in Lisp. Seems like C is the new fad there. Wait until they get bitten by macros and dangling pointers. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-16 6:02 ` jhc0033 @ 2008-07-16 21:57 ` Brian 2008-07-23 14:43 ` Michael Oswald 1 sibling, 0 replies; 61+ messages in thread From: Brian @ 2008-07-16 21:57 UTC (permalink / raw) <jhc0033@gmail.com> wrote in message news:807ef880-b2ac-4ac6-877c-21274e8ff4ab@d77g2000hsb.googlegroups.com... > On Jul 14, 4:49 am, Nick Keighley <nick_keighley_nos...@hotmail.com> > wrote: > >> contrary to popular expectations space probes are very >> conservative in their use of technolgy. > > I disagree. Actually, the space industry will try anything and stick > with it until stuff explodes (Ariane rocket) or crashes into the wrong > celestial body because of faulty software. They did use Ada widely > before, and they even programmed some of their probes in Lisp. Seems > like C is the new fad there. Wait until they get bitten by macros and > dangling pointers. And I disagree with your disagreement. The Ariane rocket disaster is a good example of trying to migrate existing software on a "known" platform in response to a business situation. Also, the crashes you refer to "because of faulty software" are examples of software that wasn't adequately tested before implementation in order to comply with non-changing, and non-changeable, mission requirements. Celestial mechanics won't let you slip your ship date! JPL, along with the rest of NASA has an extraordinary success record with their software. It would be stunning in any kind of endeavor, but is especially so when you consider the kinds of missions, and the kinds of things that happen with their funding and manpower on a yearly basis. Then, just to make the engineering problem a bit more interesting please remember that there isn't a lot of hardware that functions in that environment, and it's a few million miles from anybody who might be able to hit CTRL-ALT-DEL. With all this in mind, I think that these guys deserve a lot of respect. So, why did they choose C for this application? I wasn't there when the decision was made, but I'd suspect that it was the language that their coders were most familiar with, the language that had the right libraries for their application, and the language that they felt was most appropriate for this application. In other words, good engineering judgment. Give 'em their "props", okay? Brian ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-16 6:02 ` jhc0033 2008-07-16 21:57 ` Brian @ 2008-07-23 14:43 ` Michael Oswald 2008-07-23 22:53 ` Larry Elmore 2008-07-24 6:59 ` jhc0033 1 sibling, 2 replies; 61+ messages in thread From: Michael Oswald @ 2008-07-23 14:43 UTC (permalink / raw) jhc0033@gmail.com wrote: > They did use Ada widely > before, and they even programmed some of their probes in Lisp. Do you have some information on that? I mean, I work in the space business (although not directly on on-board software but rather mission control software and testing equipment) but I haven't heard of Lisp usage. Would definitely be a 'nice to know' for me. lg, Michael ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-23 14:43 ` Michael Oswald @ 2008-07-23 22:53 ` Larry Elmore 2008-07-24 6:59 ` jhc0033 1 sibling, 0 replies; 61+ messages in thread From: Larry Elmore @ 2008-07-23 22:53 UTC (permalink / raw) Michael Oswald wrote: > jhc0033@gmail.com wrote: > >> They did use Ada widely >> before, and they even programmed some of their probes in Lisp. > > Do you have some information on that? I mean, I work in the space > business (although not directly on on-board software but rather mission > control software and testing equipment) but I haven't heard of Lisp > usage. Would definitely be a 'nice to know' for me. NASA's Deep Space 1 ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-23 14:43 ` Michael Oswald 2008-07-23 22:53 ` Larry Elmore @ 2008-07-24 6:59 ` jhc0033 2008-07-24 7:18 ` Stefan Scholl ` (4 more replies) 1 sibling, 5 replies; 61+ messages in thread From: jhc0033 @ 2008-07-24 6:59 UTC (permalink / raw) On Jul 23, 7:43 am, Michael Oswald <muell...@gmx.net> wrote: > I mean, I work in the space > business (although not directly on on-board software but rather mission > control software and testing equipment) but I haven't heard of Lisp > usage. Would definitely be a 'nice to know' for me. Probably because they weren't too successful. I personally think Lisp is super-cool, but inappropriate for space (or any reliability- sensitive work). If I remember correctly, when they used Lisp in the probe, there was a bug and they used Lisp's live patching and interactive debugging to fix it, so they only missed their target by a quadrillion miles instead of missing it by a gazillion miles. On the other hand, the bug wouldn't have happened in the first place, if they used a good static language. I'll let someone who knows better fill in the details (that's why I added comp.lang.lisp to the groups) Happy space exploration and exploitation! ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 6:59 ` jhc0033 @ 2008-07-24 7:18 ` Stefan Scholl 2008-07-24 12:14 ` Grant Rettke 2008-07-24 7:39 ` John Thingstad ` (3 subsequent siblings) 4 siblings, 1 reply; 61+ messages in thread From: Stefan Scholl @ 2008-07-24 7:18 UTC (permalink / raw) In comp.lang.lisp jhc0033@gmail.com <jhc0033@gmail.com> wrote: > On the other hand, the bug wouldn't have happened in the first place, > if they used a good static language. Ariane 5? ;-) ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 7:18 ` Stefan Scholl @ 2008-07-24 12:14 ` Grant Rettke 0 siblings, 0 replies; 61+ messages in thread From: Grant Rettke @ 2008-07-24 12:14 UTC (permalink / raw) > Ariane 5? ;-) They should have used Eiffel ;) ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 6:59 ` jhc0033 2008-07-24 7:18 ` Stefan Scholl @ 2008-07-24 7:39 ` John Thingstad 2008-07-24 7:51 ` jhc0033 2008-07-24 8:40 ` pls.mrjm ` (2 subsequent siblings) 4 siblings, 1 reply; 61+ messages in thread From: John Thingstad @ 2008-07-24 7:39 UTC (permalink / raw) Pᅵ Thu, 24 Jul 2008 08:59:11 +0200, skrev jhc0033@gmail.com <jhc0033@gmail.com>: > On Jul 23, 7:43 am, Michael Oswald <muell...@gmx.net> wrote: >> I mean, I work in the space >> business (although not directly on on-board software but rather mission >> control software and testing equipment) but I haven't heard of Lisp >> usage. Would definitely be a 'nice to know' for me. > > Probably because they weren't too successful. I personally think Lisp > is super-cool, but inappropriate for space (or any reliability- > sensitive work). > > If I remember correctly, when they used Lisp in the probe, there was a > bug and they used Lisp's live patching and interactive debugging to > fix it, so they only missed their target by a quadrillion miles > instead of missing it by a gazillion miles. > > On the other hand, the bug wouldn't have happened in the first place, > if they used a good static language. I'll let someone who knows better > fill in the details (that's why I added comp.lang.lisp to the groups) > > Happy space exploration and exploitation! Mathematically verify it with ACL2! Way better than silly type checking. Check that theprogram does what the spec sais. (Which still only proves that it does what you say, not what you men.)) -------------- John Thingstad ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 7:39 ` John Thingstad @ 2008-07-24 7:51 ` jhc0033 2008-07-24 9:40 ` John Thingstad 2008-07-24 20:39 ` Brian 0 siblings, 2 replies; 61+ messages in thread From: jhc0033 @ 2008-07-24 7:51 UTC (permalink / raw) On Jul 24, 12:39 am, "John Thingstad" <jpth...@online.no> wrote: > Mathematically verify it with ACL2! Way better than silly type checking. > Check that theprogram does what the spec sais. > (Which still only proves that it does what you say, not what you men.)) > Typo-prone people probably shouldn't use dynamically-typed languages! BTW us, static folk, got Coq, which is probably better than ACL2: the name "ACL2" sounds like they couldn't even get it right in the first try. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 7:51 ` jhc0033 @ 2008-07-24 9:40 ` John Thingstad 2008-07-24 20:39 ` Brian 1 sibling, 0 replies; 61+ messages in thread From: John Thingstad @ 2008-07-24 9:40 UTC (permalink / raw) Pᅵ Thu, 24 Jul 2008 09:51:55 +0200, skrev jhc0033@gmail.com <jhc0033@gmail.com>: > On Jul 24, 12:39 am, "John Thingstad" <jpth...@online.no> wrote: > >> Mathematically verify it with ACL2! Way better than silly type checking. >> Check that theprogram does what the spec sais. >> (Which still only proves that it does what you say, not what you men.)) >> > > Typo-prone people probably shouldn't use dynamically-typed languages! > BTW us, static folk, got Coq, which is probably better than ACL2: the > name "ACL2" sounds like they couldn't even get it right in the first > try. Well the first post got tossed away by accident and the second was written in a hurry in aggravation. Anyhow you are wrong. Since variables must be declared before they are used and also assigned a object typo's are get caught at compile time just like in a statically compiled language. -------------- John Thingstad ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 7:51 ` jhc0033 2008-07-24 9:40 ` John Thingstad @ 2008-07-24 20:39 ` Brian 2008-07-25 6:10 ` jhc0033 1 sibling, 1 reply; 61+ messages in thread From: Brian @ 2008-07-24 20:39 UTC (permalink / raw) <jhc0033@gmail.com> wrote in message news:76fc184b-bd62-4bd3-9ccf-8a6cd872c30b@v39g2000pro.googlegroups.com... > On Jul 24, 12:39 am, "John Thingstad" <jpth...@online.no> wrote: > >> Mathematically verify it with ACL2! Way better than silly type checking. >> Check that theprogram does what the spec sais. >> (Which still only proves that it does what you say, not what you men.)) >> > > Typo-prone people probably shouldn't use dynamically-typed languages! > BTW us, static folk, got Coq, which is probably better than ACL2: the > name "ACL2" sounds like they couldn't even get it right in the first > try. You've "got Coq"??? And you're willing to talk about bad names? *grin* ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 20:39 ` Brian @ 2008-07-25 6:10 ` jhc0033 2008-07-25 20:29 ` Brian 0 siblings, 1 reply; 61+ messages in thread From: jhc0033 @ 2008-07-25 6:10 UTC (permalink / raw) On Jul 24, 1:39 pm, "Brian" <phaedrus...@hotmail.com> wrote: > <jhc0...@gmail.com> wrote in message > > news:76fc184b-bd62-4bd3-9ccf-8a6cd872c30b@v39g2000pro.googlegroups.com... > > > On Jul 24, 12:39 am, "John Thingstad" <jpth...@online.no> wrote: > > >> Mathematically verify it with ACL2! Way better than silly type checking. > >> Check that theprogram does what the spec sais. > >> (Which still only proves that it does what you say, not what you men.)) > > > Typo-prone people probably shouldn't use dynamically-typed languages! > > BTW us, static folk, got Coq, which is probably better than ACL2: the > > name "ACL2" sounds like they couldn't even get it right in the first > > try. > > You've "got Coq"??? And you're willing to talk about bad names? > *grin* I think "Coq" conveys a feeling of confidence that a theorem prover should. (Btw thanks for ruining the discussion with your low-brow shtik) ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-25 6:10 ` jhc0033 @ 2008-07-25 20:29 ` Brian 2008-07-26 3:03 ` jhc0033 0 siblings, 1 reply; 61+ messages in thread From: Brian @ 2008-07-25 20:29 UTC (permalink / raw) <jhc0033@gmail.com> wrote in message news:6e2a8ce8-25e9-427b-9c67-3285ce73e398@j7g2000prm.googlegroups.com... > On Jul 24, 1:39 pm, "Brian" <phaedrus...@hotmail.com> wrote: >> <jhc0...@gmail.com> wrote in message >> >> news:76fc184b-bd62-4bd3-9ccf-8a6cd872c30b@v39g2000pro.googlegroups.com... >> >> > On Jul 24, 12:39 am, "John Thingstad" <jpth...@online.no> wrote: >> >> >> Mathematically verify it with ACL2! Way better than silly type >> >> checking. >> >> Check that theprogram does what the spec sais. >> >> (Which still only proves that it does what you say, not what you >> >> men.)) >> >> > Typo-prone people probably shouldn't use dynamically-typed languages! >> > BTW us, static folk, got Coq, which is probably better than ACL2: the >> > name "ACL2" sounds like they couldn't even get it right in the first >> > try. >> >> You've "got Coq"??? And you're willing to talk about bad names? >> *grin* > > I think "Coq" conveys a feeling of confidence that a theorem prover > should. (Btw thanks for ruining the discussion with your low-brow > shtik) After the ACL2 comment, it seemed appropriate. I doubt if one comment "ruined" the discussion for anyone. Well, anyone other than those whose craniums are firmly emplaced in their anal orifice... (High-brow shtik is sooo much better!) Really, I find it's usually those who make tone, content or format comments that tend to bring down the discussion. A little levity rarely hurts much, and I'm sure you'll get over it. And btw, you're welcome. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-25 20:29 ` Brian @ 2008-07-26 3:03 ` jhc0033 2008-07-26 6:09 ` Brian 0 siblings, 1 reply; 61+ messages in thread From: jhc0033 @ 2008-07-26 3:03 UTC (permalink / raw) On Jul 25, 1:29 pm, "Brian" <phaedrus...@hotmail.com> wrote: > <jhc0...@gmail.com> wrote in message > > I think "Coq" conveys a feeling of confidence that a theorem prover > > should. (Btw thanks for ruining the discussion with your low-brow > > shtik) > > .... I wasn't trying to be serious. I mean, read the first sentence! Comedy is hard. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-26 3:03 ` jhc0033 @ 2008-07-26 6:09 ` Brian 0 siblings, 0 replies; 61+ messages in thread From: Brian @ 2008-07-26 6:09 UTC (permalink / raw) <jhc0033@gmail.com> wrote in message news:12db33c8-1609-4447-8ad3-97b7b45d291b@q5g2000prf.googlegroups.com... > On Jul 25, 1:29 pm, "Brian" <phaedrus...@hotmail.com> wrote: >> <jhc0...@gmail.com> wrote in message > >> > I think "Coq" conveys a feeling of confidence that a theorem prover >> > should. (Btw thanks for ruining the discussion with your low-brow >> > shtik) >> >> .... > > I wasn't trying to be serious. I mean, read the first sentence! Comedy > is hard. Sorry, not only did I mis-read, I also missed the rimshot. Goodnight Sheky! You've all been a great audience. Be sure to tip your waitresses! We'll be here all week. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 6:59 ` jhc0033 2008-07-24 7:18 ` Stefan Scholl 2008-07-24 7:39 ` John Thingstad @ 2008-07-24 8:40 ` pls.mrjm 2008-07-24 9:04 ` Pascal J. Bourguignon 2008-07-25 21:19 ` j.oke 4 siblings, 0 replies; 61+ messages in thread From: pls.mrjm @ 2008-07-24 8:40 UTC (permalink / raw) jhc0033@gmail.com ha scritto: > I personally think Lisp > is super-cool, but inappropriate for space (or any reliability- > sensitive work). You got it, this is the best way of convincing: first the cookie, then the shit! BTW, what exactly are the super-cool things you noted? :) -PM ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 6:59 ` jhc0033 ` (2 preceding siblings ...) 2008-07-24 8:40 ` pls.mrjm @ 2008-07-24 9:04 ` Pascal J. Bourguignon 2008-07-24 11:35 ` Michael Oswald 2008-07-25 21:19 ` j.oke 4 siblings, 1 reply; 61+ messages in thread From: Pascal J. Bourguignon @ 2008-07-24 9:04 UTC (permalink / raw) "jhc0033@gmail.com" <jhc0033@gmail.com> writes: > On Jul 23, 7:43 am, Michael Oswald <muell...@gmx.net> wrote: >> I mean, I work in the space >> business (although not directly on on-board software but rather mission >> control software and testing equipment) but I haven't heard of Lisp >> usage. Would definitely be a 'nice to know' for me. > > Probably because they weren't too successful. I personally think Lisp > is super-cool, but inappropriate for space (or any reliability- > sensitive work). > > If I remember correctly, when they used Lisp in the probe, there was a > bug and they used Lisp's live patching and interactive debugging to > fix it, so they only missed their target by a quadrillion miles > instead of missing it by a gazillion miles. It wasn't the purpose of the mission to hit the target, but to fly by. > On the other hand, the bug wouldn't have happened in the first place, > if they used a good static language. I'll let someone who knows better > fill in the details (that's why I added comp.lang.lisp to the groups) > > Happy space exploration and exploitation! http://en.wikipedia.org/wiki/Deep_Space_1 http://www.nasa.gov/lb/centers/ames/news/releases/1999/99_37AR.html REMOTE AGENT EXPERIMENT MEETS ALL OBJECTIVES http://web.archive.org/web/20010923215958/http://rax.arc.nasa.gov/ http://www.flownet.com/gat/jpl-lisp.html Be sure to read the description of the bug: http://web.archive.org/web/20061106012026/http://ic.arc.nasa.gov/publications/pdf/2000-0176.pdf It has nothing to do with Lisp per se. It could have occured with any other programming language. Now, the question is how do you correct a dead-lock on a running system compiled from Ada code, 3 second-light away, without rebooting it? This is what lisp allowed for this space probe, and what lisp allows also for running web servers. -- __Pascal Bourguignon__ ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 9:04 ` Pascal J. Bourguignon @ 2008-07-24 11:35 ` Michael Oswald 2008-07-24 12:15 ` Stefan Scholl 0 siblings, 1 reply; 61+ messages in thread From: Michael Oswald @ 2008-07-24 11:35 UTC (permalink / raw) Pascal J. Bourguignon wrote: > http://en.wikipedia.org/wiki/Deep_Space_1 > > http://www.nasa.gov/lb/centers/ames/news/releases/1999/99_37AR.html > REMOTE AGENT EXPERIMENT MEETS ALL OBJECTIVES > > http://web.archive.org/web/20010923215958/http://rax.arc.nasa.gov/ > > http://www.flownet.com/gat/jpl-lisp.html > > Be sure to read the description of the bug: > > http://web.archive.org/web/20061106012026/http://ic.arc.nasa.gov/publications/pdf/2000-0176.pdf > > It has nothing to do with Lisp per se. It could have occured with any > other programming language. Now, the question is how do you correct a > dead-lock on a running system compiled from Ada code, 3 second-light > away, without rebooting it? This is what lisp allowed for this space > probe, and what lisp allows also for running web servers. > Thanks for the links! Very interesting. It also makes sense to me to put Lisp into this Remote Agent unit (which doesn't seem to be very time critical and also doesn't deal with low level stuff but is rather on a high level). So each language can play out it's strengths. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 11:35 ` Michael Oswald @ 2008-07-24 12:15 ` Stefan Scholl 2008-07-24 12:36 ` Michael Oswald 0 siblings, 1 reply; 61+ messages in thread From: Stefan Scholl @ 2008-07-24 12:15 UTC (permalink / raw) In comp.lang.lisp Michael Oswald <muell_om@gmx.net> wrote: > Very interesting. It also makes sense to me to put Lisp into this Remote > Agent unit (which doesn't seem to be very time critical and also doesn't > deal with low level stuff but is rather on a high level). > So each language can play out it's strengths. Subtle trolling. Gratuliere. -- Web (en): http://www.no-spoon.de/ -*- Web (de): http://www.frell.de/ ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 12:15 ` Stefan Scholl @ 2008-07-24 12:36 ` Michael Oswald 0 siblings, 0 replies; 61+ messages in thread From: Michael Oswald @ 2008-07-24 12:36 UTC (permalink / raw) Stefan Scholl wrote: > Subtle trolling. Gratuliere. What's your problem? ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-24 6:59 ` jhc0033 ` (3 preceding siblings ...) 2008-07-24 9:04 ` Pascal J. Bourguignon @ 2008-07-25 21:19 ` j.oke 2008-07-25 22:34 ` Adam Beneschan 4 siblings, 1 reply; 61+ messages in thread From: j.oke @ 2008-07-25 21:19 UTC (permalink / raw) On 24 Lug, 08:59, "jhc0...@gmail.com" <jhc0...@gmail.com> wrote: > is super-cool On 24 Lug, 08:59, "jhc0...@gmail.com" <jhc0...@gmail.com> wrote: > ... super-cool ... What's the better language: hebrew or english? Well, the first one is simple and perfect, and the second one goes all for convenience (mixed to european history, which took origin from latin, which took origin from greek, which took origin from egyptian, which took origin from hebrew (and so the circle is finally closed again)). <-- please note: we have to close 2 (two) parens here, which seems to be a real problem to all the non-Lispers out there... So what? (The translation to coding slangs is left as an exercise to the reader (no, the human one)). <-- yet another one!! -JO ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-25 21:19 ` j.oke @ 2008-07-25 22:34 ` Adam Beneschan 2008-07-25 23:30 ` Joost Kremers ` (2 more replies) 0 siblings, 3 replies; 61+ messages in thread From: Adam Beneschan @ 2008-07-25 22:34 UTC (permalink / raw) On Jul 25, 2:19 pm, "j.oke" <java....@gmail.com> wrote: > On 24 Lug, 08:59, "jhc0...@gmail.com" <jhc0...@gmail.com> wrote: > > > is super-cool > > On 24 Lug, 08:59, "jhc0...@gmail.com" <jhc0...@gmail.com> wrote: > > > ... super-cool ... > > What's the better language: hebrew or english? > > Well, the first one is simple and perfect, and the second one goes all > for convenience (mixed to european history, which took origin from > latin, which took origin from greek, which took origin from egyptian, > which took origin from hebrew (and so the circle is finally closed > again)). Ummm, no. I think you're talking about the *alphabet*, not the language. The English language is part of a large group of languages called Indo-European, and Hebrew isn't part of this group (nor is Egyptian). Where this language originated is controversial; one theory is somewhere northeast of the Black Sea. I don't think you're quite right about the alphabets, either; the Greek and Hebrew alphabets are both more or less directly derived from the Phoenician alphabet, and Egyptian hieroglyphics don't figure into it at all. > ... super-pedantic ... -- Adam ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-25 22:34 ` Adam Beneschan @ 2008-07-25 23:30 ` Joost Kremers 2008-07-26 12:41 ` j.oke 2008-07-26 12:51 ` j.oke 2 siblings, 0 replies; 61+ messages in thread From: Joost Kremers @ 2008-07-25 23:30 UTC (permalink / raw) Adam Beneschan wrote: > the Greek and Hebrew > alphabets are both more or less directly derived from the Phoenician > alphabet, and Egyptian hieroglyphics don't figure into it at all. actually, i believe the consensus is that the proto-semitic alphabet from which the phoenician alphabet developed, was directly derived from egyptian hieroglyphics. -- Joost Kremers joostkremers@yahoo.com Selbst in die Unterwelt dringt durch Spalten Licht EN:SiS(9) ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-25 22:34 ` Adam Beneschan 2008-07-25 23:30 ` Joost Kremers @ 2008-07-26 12:41 ` j.oke 2008-07-26 12:51 ` j.oke 2 siblings, 0 replies; 61+ messages in thread From: j.oke @ 2008-07-26 12:41 UTC (permalink / raw) On 26 Lug, 00:34, Adam Beneschan <a...@irvine.com> wrote: > no. There's much more thought in it (between the lines) than it might seem (at a first/fast/superficial glance), but I don't expect anybody to waste too much hours on meditating on it. ;) -JO ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-25 22:34 ` Adam Beneschan 2008-07-25 23:30 ` Joost Kremers 2008-07-26 12:41 ` j.oke @ 2008-07-26 12:51 ` j.oke 2 siblings, 0 replies; 61+ messages in thread From: j.oke @ 2008-07-26 12:51 UTC (permalink / raw) On 26 Lug, 00:34, Adam Beneschan <a...@irvine.com> wrote: > I think you're talking about the *alphabet*, not the > language. I wrote (and meant): history. -JO ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-14 11:49 ` Nick Keighley 2008-07-15 7:27 ` Maciej Sobczak 2008-07-16 6:02 ` jhc0033 @ 2008-07-17 21:56 ` Paul Hsieh 2008-07-17 22:30 ` Chris Thomasson ` (3 more replies) 2 siblings, 4 replies; 61+ messages in thread From: Paul Hsieh @ 2008-07-17 21:56 UTC (permalink / raw) On Jul 14, 4:49 am, Nick Keighley <nick_keighley_nos...@hotmail.com> wrote: > On 14 Jul, 12:18, "jhc0...@gmail.com" <jhc0...@gmail.com> wrote: > > > Interesting article I came across on Slashdot: > > >http://developers.slashdot.org/developers/08/07/10/213211.shtml > > > They are using C at JPL to program Mars Lander and just about > > everything now! Not Ada. Anyone got an explanation? I wonder also, do > > they really mean C++ when they say C. In my experience, this is a > > frequent, although disagreeable usage. > > contrary to popular expectations space probes are very > conservative in their use of technology. Processors are old > (and hence proven) memories are small (less vulnerable to radiation). Indeed. Ada is used by the military, because they have much more sophisticated hardware in tanks and fighter jets. I would expect that perhaps NASA also uses it for the space shuttle. > Remember if there's a bug they can't just upgrade the software. They both can and *DO* do this. They typically use VxWorks as the main operating system, which comes with a fairly powerful command console that makes it practical to actually debug, upload bug fixes and reboot the systems all remotely. > Well they can but it has to be mostly working for the download > to work. Its in the OS they use (and didn't make themselves.) > These are essentially embedded systems and C is still popular > in that world. The small memory footprint and VxWorks environment probably makes C a very attractive language for the NASA guys. If they used Ada, they would be slower, have much larger memory requirements and have a very hard time debugging problems remotely. > I suspect its a damn sight easier to prove C correct than C++. Well by definition, since every C bug can be mapped to a C++ bug (except for certain implicit type conversion failures; but that can be dealt with by requiring that the C code also be compilable with a C++ compiler.) -- Paul Hsieh http://www.pobox.com/~qed/ http://bstring.sf.net/ ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-17 21:56 ` Paul Hsieh @ 2008-07-17 22:30 ` Chris Thomasson 2008-07-17 23:03 ` Default User 2008-07-18 0:02 ` Gary Scott 2008-07-18 18:02 ` Colin Paul Gloster ` (2 subsequent siblings) 3 siblings, 2 replies; 61+ messages in thread From: Chris Thomasson @ 2008-07-17 22:30 UTC (permalink / raw) "Paul Hsieh" <websnarf@gmail.com> wrote in message news:13a2f4f0-6ec1-4570-b6bf-1621cfb32db2@a2g2000prm.googlegroups.com... On Jul 14, 4:49 am, Nick Keighley <nick_keighley_nos...@hotmail.com> wrote: > > On 14 Jul, 12:18, "jhc0...@gmail.com" <jhc0...@gmail.com> wrote: > > > > > Interesting article I came across on Slashdot: > > > > >http://developers.slashdot.org/developers/08/07/10/213211.shtml > > > > > They are using C at JPL to program Mars Lander and just about > > > everything now! Not Ada. Anyone got an explanation? I wonder also, do > > > they really mean C++ when they say C. In my experience, this is a > > > frequent, although disagreeable usage. > > > > contrary to popular expectations space probes are very > > conservative in their use of technology. Processors are old > > (and hence proven) memories are small (less vulnerable to radiation). > Indeed. Ada is used by the military, because they have much more > sophisticated hardware in tanks and fighter jets. Is this a trolling attempt? Anyway, the military uses C++ for all critical system software in state-of-the-art fighter-bombers because they have much more sophisticated hardware: http://www.research.att.com/~bs/JSF-AV-rules.pdf http://www.ldra.co.uk/nologindownload.asp?id=52 :^/ > I would expect that > perhaps NASA also uses it for the space shuttle. [...] ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-17 22:30 ` Chris Thomasson @ 2008-07-17 23:03 ` Default User 2008-07-18 0:03 ` Chris Thomasson 2008-07-18 0:02 ` Gary Scott 1 sibling, 1 reply; 61+ messages in thread From: Default User @ 2008-07-17 23:03 UTC (permalink / raw) Chris Thomasson wrote: > "Paul Hsieh" <websnarf@gmail.com> wrote in message > news:13a2f4f0-6ec1-4570-b6bf-1621cfb32db2@a2g2000prm.googlegroups.com. > > Indeed. Ada is used by the military, because they have much more > > sophisticated hardware in tanks and fighter jets. > > Is this a trolling attempt? Anyway, the military uses C++ for all > critical system software in state-of-the-art fighter-bombers because > they have much more sophisticated hardware: We did quite a bit of code for avionics flight systems for military aircraft in C++. It ran on top of an RTOS and there were certain restrictions in the programming. Dynamic memory was only allocated at startup, for instance. Brian ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-17 23:03 ` Default User @ 2008-07-18 0:03 ` Chris Thomasson 0 siblings, 0 replies; 61+ messages in thread From: Chris Thomasson @ 2008-07-18 0:03 UTC (permalink / raw) "Default User" <defaultuserbr@yahoo.com> wrote in message news:6ea1d5F65269U1@mid.individual.net... > Chris Thomasson wrote: > >> "Paul Hsieh" <websnarf@gmail.com> wrote in message >> news:13a2f4f0-6ec1-4570-b6bf-1621cfb32db2@a2g2000prm.googlegroups.com. > >> > Indeed. Ada is used by the military, because they have much more >> > sophisticated hardware in tanks and fighter jets. >> >> Is this a trolling attempt? Anyway, the military uses C++ for all >> critical system software in state-of-the-art fighter-bombers because >> they have much more sophisticated hardware: > > We did quite a bit of code for avionics flight systems for military > aircraft in C++. It ran on top of an RTOS and there were certain > restrictions in the programming. Dynamic memory was only allocated at > startup, for instance. Sounds pretty smart to me. IMHO, its nice that C++ is flexible enough to work well under some fairly harsh, but necessary restrictions. Also, IMVHO, it does not really matter what programming language is used because in the end its all up to the programmer to "get it right". Even an ADA- based system could contain subtle logic bugs. That would be very bad if one of those nasty bugs revealed a code-path which could open the bomb bay doors, arm something and let it loose! :^o ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-17 22:30 ` Chris Thomasson 2008-07-17 23:03 ` Default User @ 2008-07-18 0:02 ` Gary Scott 2008-07-18 0:08 ` Chris Thomasson 1 sibling, 1 reply; 61+ messages in thread From: Gary Scott @ 2008-07-18 0:02 UTC (permalink / raw) Chris Thomasson wrote: > "Paul Hsieh" <websnarf@gmail.com> wrote in message > news:13a2f4f0-6ec1-4570-b6bf-1621cfb32db2@a2g2000prm.googlegroups.com... > On Jul 14, 4:49 am, Nick Keighley <nick_keighley_nos...@hotmail.com> > wrote: > >> > On 14 Jul, 12:18, "jhc0...@gmail.com" <jhc0...@gmail.com> wrote: >> > >> > > Interesting article I came across on Slashdot: >> > >> > >http://developers.slashdot.org/developers/08/07/10/213211.shtml >> > >> > > They are using C at JPL to program Mars Lander and just about >> > > everything now! Not Ada. Anyone got an explanation? I wonder also, do >> > > they really mean C++ when they say C. In my experience, this is a >> > > frequent, although disagreeable usage. >> > >> > contrary to popular expectations space probes are very >> > conservative in their use of technology. Processors are old >> > (and hence proven) memories are small (less vulnerable to radiation). > > >> Indeed. Ada is used by the military, because they have much more >> sophisticated hardware in tanks and fighter jets. > > > Is this a trolling attempt? Anyway, the military uses C++ for all critical > system software in state-of-the-art fighter-bombers because they have much > more sophisticated hardware: > > http://www.research.att.com/~bs/JSF-AV-rules.pdf > > http://www.ldra.co.uk/nologindownload.asp?id=52 It has very little to do with the "sophistication of the hardware". > > :^/ > > > > >> I would expect that >> perhaps NASA also uses it for the space shuttle. > > > [...] -- Gary Scott mailto:garylscott@sbcglobal dot net Fortran Library: http://www.fortranlib.com Support the Original G95 Project: http://www.g95.org -OR- Support the GNU GFortran Project: http://gcc.gnu.org/fortran/index.html If you want to do the impossible, don't hire an expert because he knows it can't be done. -- Henry Ford ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-18 0:02 ` Gary Scott @ 2008-07-18 0:08 ` Chris Thomasson 0 siblings, 0 replies; 61+ messages in thread From: Chris Thomasson @ 2008-07-18 0:08 UTC (permalink / raw) "Gary Scott" <garylscott@sbcglobal.net> wrote in message news:d4Rfk.33338$ZE5.20098@nlpi061.nbdc.sbc.com... > Chris Thomasson wrote: > >> "Paul Hsieh" <websnarf@gmail.com> wrote in message >> news:13a2f4f0-6ec1-4570-b6bf-1621cfb32db2@a2g2000prm.googlegroups.com... >> On Jul 14, 4:49 am, Nick Keighley <nick_keighley_nos...@hotmail.com> >> wrote: >> >>> > On 14 Jul, 12:18, "jhc0...@gmail.com" <jhc0...@gmail.com> wrote: >>> > >>> > > Interesting article I came across on Slashdot: >>> > >>> > >http://developers.slashdot.org/developers/08/07/10/213211.shtml >>> > >>> > > They are using C at JPL to program Mars Lander and just about >>> > > everything now! Not Ada. Anyone got an explanation? I wonder also, >>> > > do >>> > > they really mean C++ when they say C. In my experience, this is a >>> > > frequent, although disagreeable usage. >>> > >>> > contrary to popular expectations space probes are very >>> > conservative in their use of technology. Processors are old >>> > (and hence proven) memories are small (less vulnerable to radiation). >> >> >>> Indeed. Ada is used by the military, because they have much more >>> sophisticated hardware in tanks and fighter jets. >> >> >> Is this a trolling attempt? Anyway, the military uses C++ for all >> critical >> system software in state-of-the-art fighter-bombers because they have >> much >> more sophisticated hardware: >> >> http://www.research.att.com/~bs/JSF-AV-rules.pdf >> >> http://www.ldra.co.uk/nologindownload.asp?id=52 > > It has very little to do with the "sophistication of the hardware". [...] Yeah, I was "trying" to be sarcastic. :^( ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-17 21:56 ` Paul Hsieh 2008-07-17 22:30 ` Chris Thomasson @ 2008-07-18 18:02 ` Colin Paul Gloster 2008-07-18 18:51 ` Dmitry A. Kazakov 2008-07-18 18:37 ` Pascal Obry 2008-07-18 19:45 ` Gautier 3 siblings, 1 reply; 61+ messages in thread From: Colin Paul Gloster @ 2008-07-18 18:02 UTC (permalink / raw) [-- Warning: decoded text below may be mangled, UTF-8 assumed --] [-- Attachment #1: Type: TEXT/PLAIN; charset=UTF-8, Size: 8734 bytes --] On Thu, 17 Jul 2008, Paul Hsieh wrote: |-------------------------------------------------------------------------| |"On Jul 14, 4:49 am, Nick Keighley <nick_keighley_nos...@hotmail.com> | |wrote: | |> On 14 Jul, 12:18, "jhc0...@gmail.com" <jhc0...@gmail.com> wrote: | |> | |> > Interesting article I came across on Slashdot: | |> | |> >http://developers.slashdot.org/developers/08/07/10/213211.shtml | |> | |> > They are using C at JPL to program Mars Lander and just about | |> > everything now! Not Ada. Anyone got an explanation? I wonder also, do| |> > they really mean C++ when they say C. In my experience, this is a | |> > frequent, although disagreeable usage. | |> | |> contrary to popular expectations space probes are very | |> conservative in their use of technology. Processors are old | |> (and hence proven) [..] | | | |Indeed." | |-------------------------------------------------------------------------| Agreed. |-------------------------------------------------------------------------| |" memories are small" | |-------------------------------------------------------------------------| Agreed (in the sense that they do not have many binary digits). |-------------------------------------------------------------------------| |" (less vulnerable to radiation)." | |-------------------------------------------------------------------------| Memories used in space probes are less vulnerable to radiation than normal memories, but this is not because of the centimeters cubed used. On Page 12 of HTTP://AMS.Aeroflex.com/ProductFiles/DataSheets/4MSRAM/ut8r512x8.pdf , dimensions of 0.575 inches by 0.910 inches by (0.117-0.013) inches (approximately 14.6 millimeters by 23.1 mm by 2.6 mm approximately equal to 877 mm cubed) are shown for an astronautical four megabit SRAM excluding the legs, whereas we can see from WWW.IDT.com/?genID=71V416L&source=products_genericPart_71V416L and WWW.IDT.com/?app=packaging&packageID=BE48&mktseg=IDT that dimensions closer to 9 mm by 9 mm by 1.2 mm (97.2 mm cubed) are available for four megabits of Terran SRAM. Of course, a problem with radiation is more likely to happen to (2 x 877) mm cubed of 2 x 4 Mbits of SRAM than to 1 x 877 mm cubed of 1 x 4 Mbits of SRAM. |-------------------------------------------------------------------------| |" Ada [..] | |[..] | |[..] I would expect that | |perhaps NASA also uses it for the space shuttle." | |-------------------------------------------------------------------------| I have heard that a language which is used only for the Space Shuttles was used instead. |-------------------------------------------------------------------------| |> Remember if there's a bug they can't just upgrade the software. | | | |They both can and *DO* do this." | |-------------------------------------------------------------------------| They can upgrade the software. They can not do this easily, so Nick Keighley's assertion "they can't just upgrade the software" is correct. Were the probe on the Moon, there would be a latency |-------------------------------------------------------------------------| |" They typically use VxWorks as the | |main operating system," | |-------------------------------------------------------------------------| Actually before the rovers launched in circa 2003, NASA used to not use VxWorks. A port of VxWorks to a processor which had not been supported before was specifically written for that mission. This is in contrast to the often conservative nature of responsible astronautical engineers, but NASA has shown itself to be reckless on a number of occasions. |-------------------------------------------------------------------------| |" which comes with a fairly powerful command | |console that makes it practical to actually debug, upload bug fixes | |and reboot the systems all remotely. | | | |> Well they can but it has to be mostly working for the download | |> to work. | | | |Its in the OS they use (and didn't make themselves.)" | |-------------------------------------------------------------------------| Were the probe on the Moon, the latency would be a few seconds long. Latencies for other destinations would be much worse. If Mars was at its closest to the Sun (i.e. at 1.381 Astronomical Units (A.U.s)) and were Earth between the Sun and Mars, then there would be a distance of approximately 0.381 A.U.s equal to circa 500 light seconds multiplied by 0.381 equals 190.5 light seconds equals over three light minutes between the Earthling operators and the probe. Between the time an operator typed ps to list the processes and the time the telecommand was received over three minutes later, plenty of terminal problems could have ended the mission. If you have software on the probe which is sorting ten numbers while you are uploading a patch to the sorting algorithhm, and pausing or terminating the current sorting is unacceptable (it might not actually be buggy, perhaps it merely needs an adjustment), then does VxWorks know that the only safe times to install the patch are between one run's final iteration and the next run's next iteration. VxWorks can not possibly know that without being told. This is independent of operating system and language. Are you aware that well-maintained unmanned spacecraft are not rebooted even when software is being patched while most of the rest of the software is still being run? |-------------------------------------------------------------------------| |"[..] | | | |The small memory footprint and VxWorks environment probably makes C a | |very attractive language for the NASA guys. If they used Ada, they | |would be slower, have much larger memory requirements and have a very | |hard time debugging problems remotely. | | | |[..]" | |-------------------------------------------------------------------------| How is C on VxWorks faster than Ada? It is not clear to me whether you believe that C on VxWorks makes the speed of light faster or whether it teleports Mars to be situated closer to Earth. Please explain the speeds of less than two microseconds without VxWorks and over eight seconds with VxWorks in Table 1 of "The Ravenscar Tasking Profile - Experience Report" by Brian Dobbing and George Romanski in the PDF file hyperlinked to from HTTP://Portal.ACM.org/citation.cfm?id=329607.334733&coll=Portal&dl=GUIDE&CFID=37194600&CFTOKEN=70659176 VxWorks consumes "36KB" according to WWW.Windriver.com/products/product-notes/Platform-for-Network-Equipment-ve-Note.pdf whereas the Ada runtime overhead for Aonix ObjectRaven was claimed to be less than five kilobytes in Table 2. Please explain how Ada using less than five kilobytes is a "much larger memory" requirement than C using 36KB. Please show me something in your post about Ada which is not nonsense. Sincerely, Colin Paul Gloster ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-18 18:02 ` Colin Paul Gloster @ 2008-07-18 18:51 ` Dmitry A. Kazakov 0 siblings, 0 replies; 61+ messages in thread From: Dmitry A. Kazakov @ 2008-07-18 18:51 UTC (permalink / raw) On Fri, 18 Jul 2008 19:02:58 +0100, Colin Paul Gloster wrote: > On Thu, 17 Jul 2008, Paul Hsieh wrote: > >|The small memory footprint and VxWorks environment probably makes C a >|very attractive language for the NASA guys. If they used Ada, they >|would be slower, have much larger memory requirements and have a very >|hard time debugging problems remotely. > > How is C on VxWorks faster than Ada? As a part of religious experience, I guess... Actually some VxWorks guys, who are aware of Ada, tried to convince us that our project on VxWorks should use C, rather than Ada, because "C is faster." -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-17 21:56 ` Paul Hsieh 2008-07-17 22:30 ` Chris Thomasson 2008-07-18 18:02 ` Colin Paul Gloster @ 2008-07-18 18:37 ` Pascal Obry 2008-07-18 19:45 ` Gautier 3 siblings, 0 replies; 61+ messages in thread From: Pascal Obry @ 2008-07-18 18:37 UTC (permalink / raw) To: Paul Hsieh Paul, > The small memory footprint and VxWorks environment probably makes C a > very attractive language for the NASA guys. If they used Ada, they > would be slower, have much larger memory requirements and have a very > hard time debugging problems remotely. That's just good-old-wrong-assumption made by lot of people. Ada is slower? I see nothing slow in Ada which is a language. Does a language has speed now? More seriously, some benchmarks have shown that some Ada compiler have been generating faster code than C compiler on a given application. And of course, some other benchmarks have shown the opposite. The memory requirement for Ada is wrong too. Using a zero-foot-print runtime you have zero memory requirement from the runtime. >> I suspect its a damn sight easier to prove C correct than C++. Still lot easier to prove Ada correct. And in any case on critical applications there is no Ada nor C but some subset that makes the languages safer (e.g. SPARK for Ada or MISRA-C for C). Please let's try to at least have constructive criticisms. Thanks. Pascal. -- --|------------------------------------------------------ --| Pascal Obry Team-Ada Member --| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE --|------------------------------------------------------ --| http://www.obry.net --| "The best way to travel is by means of imagination" --| --| gpg --keyserver wwwkeys.pgp.net --recv-key C1082595 ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-17 21:56 ` Paul Hsieh ` (2 preceding siblings ...) 2008-07-18 18:37 ` Pascal Obry @ 2008-07-18 19:45 ` Gautier 2008-07-18 20:26 ` jacob navia ` (2 more replies) 3 siblings, 3 replies; 61+ messages in thread From: Gautier @ 2008-07-18 19:45 UTC (permalink / raw) Paul Hsieh: > The small memory footprint and VxWorks environment probably makes C a > very attractive language for the NASA guys. If they used Ada, they > would be slower, Oooh... This is a misconception that comes from the time of non-optimizing compilers for PC's - around 20 years ago. At that time a i++ was faster than a i:= i + 1, sure. But it was long long time ago. Never heard of GCC ?... _________________________________________________________ Gautier's Ada programming -- http://sf.net/users/gdemont/ NB: For a direct answer, e-mail address on the Web site! ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-18 19:45 ` Gautier @ 2008-07-18 20:26 ` jacob navia 2008-07-18 21:01 ` Georg Bauhaus 2008-07-18 21:14 ` Gary Scott 2008-07-18 20:45 ` Richard Tobin 2008-07-22 8:39 ` Jean-Pierre Rosen 2 siblings, 2 replies; 61+ messages in thread From: jacob navia @ 2008-07-18 20:26 UTC (permalink / raw) Gautier wrote: > Paul Hsieh: > >> The small memory footprint and VxWorks environment probably makes C a >> very attractive language for the NASA guys. If they used Ada, they >> would be slower, > > Oooh... This is a misconception that comes from the time of > non-optimizing compilers for PC's - around 20 years ago. At that time a > i++ was faster than a i:= i + 1, sure. But it was long long time ago. > Never heard of GCC ?... > _________________________________________________________ > Gautier's Ada programming -- http://sf.net/users/gdemont/ > > NB: For a direct answer, e-mail address on the Web site! Do you have any data to prove that ADA is faster than C? Or that has a smaller memory footprint? -- jacob navia jacob at jacob point remcomp point fr logiciels/informatique http://www.cs.virginia.edu/~lcc-win32 ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-18 20:26 ` jacob navia @ 2008-07-18 21:01 ` Georg Bauhaus 2008-07-18 21:14 ` Gary Scott 1 sibling, 0 replies; 61+ messages in thread From: Georg Bauhaus @ 2008-07-18 21:01 UTC (permalink / raw) jacob navia wrote: > Do you have any data to prove that ADA is faster than C? > Or that has a smaller memory footprint? Oh, not that again. ;-) I'm sure that Jacob, being a compiler writer, is perfectly aware of how and when some +1 on a variable in either language can and will be mapped to the same instruction(s). Etc. Earlier, Keith Thompson said the wonderful words, "This was cross-posted to comp.lang.ada and comp.lang.c. I suggest we all refuse to take the bait and *not* start a cross-language flame war." -- Georg Bauhaus Y A Time Drain http://www.9toX.de ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-18 20:26 ` jacob navia 2008-07-18 21:01 ` Georg Bauhaus @ 2008-07-18 21:14 ` Gary Scott 1 sibling, 0 replies; 61+ messages in thread From: Gary Scott @ 2008-07-18 21:14 UTC (permalink / raw) jacob navia wrote: > Gautier wrote: > >> Paul Hsieh: >> >>> The small memory footprint and VxWorks environment probably makes C a >>> very attractive language for the NASA guys. If they used Ada, they >>> would be slower, >> >> >> Oooh... This is a misconception that comes from the time of >> non-optimizing compilers for PC's - around 20 years ago. At that time >> a i++ was faster than a i:= i + 1, sure. But it was long long time >> ago. Never heard of GCC ?... >> _________________________________________________________ >> Gautier's Ada programming -- http://sf.net/users/gdemont/ >> >> NB: For a direct answer, e-mail address on the Web site! > > > Do you have any data to prove that ADA is faster than C? There should in general be no difference other than that there may be some constructs that are harder for the compiler writer to figure out how to optimize in one language versus the other. Probably works both ways. > Or that has a smaller memory footprint? > > > -- Gary Scott mailto:garylscott@sbcglobal dot net Fortran Library: http://www.fortranlib.com Support the Original G95 Project: http://www.g95.org -OR- Support the GNU GFortran Project: http://gcc.gnu.org/fortran/index.html If you want to do the impossible, don't hire an expert because he knows it can't be done. -- Henry Ford ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-18 19:45 ` Gautier 2008-07-18 20:26 ` jacob navia @ 2008-07-18 20:45 ` Richard Tobin 2008-07-22 8:39 ` Jean-Pierre Rosen 2 siblings, 0 replies; 61+ messages in thread From: Richard Tobin @ 2008-07-18 20:45 UTC (permalink / raw) In article <4880f2ed$1_6@news.bluewin.ch>, Gautier <gautier@fakeaddress.nil> wrote: >Oooh... This is a misconception that comes from the time of >non-optimizing compilers for PC's - around 20 years ago. At that time a >i++ was faster than a i:= i + 1, sure. I'd have been very disappointed with a compiler that did that 20 years ago. >Never heard of GCC ?... Why yes, we were using it 20 years ago! -- Richard -- Please remember to mention me / in tapes you leave behind. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-18 19:45 ` Gautier 2008-07-18 20:26 ` jacob navia 2008-07-18 20:45 ` Richard Tobin @ 2008-07-22 8:39 ` Jean-Pierre Rosen 2008-07-22 10:45 ` Nick Keighley 2 siblings, 1 reply; 61+ messages in thread From: Jean-Pierre Rosen @ 2008-07-22 8:39 UTC (permalink / raw) Gautier a �crit : > Paul Hsieh: > >> The small memory footprint and VxWorks environment probably makes C a >> very attractive language for the NASA guys. If they used Ada, they >> would be slower, > > Oooh... This is a misconception that comes from the time of > non-optimizing compilers for PC's - around 20 years ago. At that time a > i++ was faster than a i:= i + 1, sure. But it was long long time ago. > Never heard of GCC ?... When I started working on a (Pascal) compiler, this optimization was the first one I introduced in the compiler, because it was the easiest one to do. And it was 30 years ago... -- --------------------------------------------------------- J-P. Rosen (rosen@adalog.fr) Visit Adalog's web site at http://www.adalog.fr ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-22 8:39 ` Jean-Pierre Rosen @ 2008-07-22 10:45 ` Nick Keighley 2008-07-22 10:50 ` Richard ` (3 more replies) 0 siblings, 4 replies; 61+ messages in thread From: Nick Keighley @ 2008-07-22 10:45 UTC (permalink / raw) On 22 Jul, 09:39, Jean-Pierre Rosen <ro...@adalog.fr> wrote: > Gautier a écrit : <snip> > > [this] comes from the time of > > non-optimizing compilers for PC's - around 20 years ago. At that time a > > i++ was faster than a i:= i + 1, sure. But it was long long time ago. > > Never heard of GCC ?... > > When I started working on a (Pascal) compiler, this optimization was the > first one I introduced in the compiler, because it was the easiest one > to do. And it was 30 years ago... Pascal has a ++ operator? -- Nick Keighley ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-22 10:45 ` Nick Keighley @ 2008-07-22 10:50 ` Richard 2008-07-22 11:20 ` Jean-Pierre Rosen ` (2 subsequent siblings) 3 siblings, 0 replies; 61+ messages in thread From: Richard @ 2008-07-22 10:50 UTC (permalink / raw) Nick Keighley <nick_keighley_nospam@hotmail.com> writes: > On 22 Jul, 09:39, Jean-Pierre Rosen <ro...@adalog.fr> wrote: >> Gautier a écrit : > > <snip> > >> > [this] comes from the time of >> > non-optimizing compilers for PC's - around 20 years ago. At that time a >> > i++ was faster than a i:= i + 1, sure. But it was long long time ago. >> > Never heard of GCC ?... >> >> When I started working on a (Pascal) compiler, this optimization was the >> first one I introduced in the compiler, because it was the easiest one >> to do. And it was 30 years ago... > > Pascal has a ++ operator? It was probably added as lesson 2 in an under graduate compiler course. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-22 10:45 ` Nick Keighley 2008-07-22 10:50 ` Richard @ 2008-07-22 11:20 ` Jean-Pierre Rosen 2008-07-22 21:11 ` CBFalconer 2008-07-22 12:05 ` Chris Dollin 2008-07-22 13:39 ` Walter Banks 3 siblings, 1 reply; 61+ messages in thread From: Jean-Pierre Rosen @ 2008-07-22 11:20 UTC (permalink / raw) Nick Keighley a �crit : > On 22 Jul, 09:39, Jean-Pierre Rosen <ro...@adalog.fr> wrote: >> Gautier a �crit : > > <snip> > >>> [this] comes from the time of >>> non-optimizing compilers for PC's - around 20 years ago. At that time a >>> i++ was faster than a i:= i + 1, sure. But it was long long time ago. >>> Never heard of GCC ?... >> When I started working on a (Pascal) compiler, this optimization was the >> first one I introduced in the compiler, because it was the easiest one >> to do. And it was 30 years ago... > > Pascal has a ++ operator? > No, I was refering to optimizing I := I+1 into a single "Inc" machine instruction. -- --------------------------------------------------------- J-P. Rosen (rosen@adalog.fr) Visit Adalog's web site at http://www.adalog.fr ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-22 11:20 ` Jean-Pierre Rosen @ 2008-07-22 21:11 ` CBFalconer 2008-07-23 8:40 ` Jean-Pierre Rosen 2008-07-26 11:13 ` Antoninus Twink 0 siblings, 2 replies; 61+ messages in thread From: CBFalconer @ 2008-07-22 21:11 UTC (permalink / raw) Jean-Pierre Rosen wrote: > Nick Keighley a �crit : >> Jean-Pierre Rosen <ro...@adalog.fr> wrote: >>> Gautier a �crit : >> >> <snip> >> >>>> [this] comes from the time of non-optimizing compilers for PC's >>>> - around 20 years ago. At that time a i++ was faster than a >>>> i:= i + 1, sure. But it was long long time ago. >>>> >>>> Never heard of GCC ?... >>> >>> When I started working on a (Pascal) compiler, this optimization >>> was the first one I introduced in the compiler, because it was >>> the easiest one to do. And it was 30 years ago... >> >> Pascal has a ++ operator? > > No, I was refering to optimizing I := I+1 into a single "Inc" > machine instruction. ISO Standard Pascal has no 'inc' instruction. Some non-standard abortions do. However those abortions also omit critical portions of the standard, such as f^ and the put and get functions. There is more. -- [mail]: Chuck F (cbfalconer at maineline dot net) [page]: <http://cbfalconer.home.att.net> Try the download section. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-22 21:11 ` CBFalconer @ 2008-07-23 8:40 ` Jean-Pierre Rosen 2008-07-23 13:00 ` CBFalconer 2008-07-26 11:13 ` Antoninus Twink 1 sibling, 1 reply; 61+ messages in thread From: Jean-Pierre Rosen @ 2008-07-23 8:40 UTC (permalink / raw) CBFalconer a �crit : >> No, I was refering to optimizing I := I+1 into a single "Inc" >> machine instruction. > > ISO Standard Pascal has no 'inc' instruction. Some non-standard > abortions do. However those abortions also omit critical portions > of the standard, such as f^ and the put and get functions. There > is more. > Please read again, I was refering to the Inc /machine instruction/ that we had for our target at that time (an IRIS-80, a french machine derived from XDS-Sigma7). -- --------------------------------------------------------- J-P. Rosen (rosen@adalog.fr) Visit Adalog's web site at http://www.adalog.fr ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-23 8:40 ` Jean-Pierre Rosen @ 2008-07-23 13:00 ` CBFalconer 0 siblings, 0 replies; 61+ messages in thread From: CBFalconer @ 2008-07-23 13:00 UTC (permalink / raw) Jean-Pierre Rosen wrote: > CBFalconer a �crit : > >>> No, I was refering to optimizing I := I+1 into a single "Inc" >>> machine instruction. >> >> ISO Standard Pascal has no 'inc' instruction. Some non-standard >> abortions do. However those abortions also omit critical portions >> of the standard, such as f^ and the put and get functions. There >> is more. > > Please read again, I was refering to the Inc /machine instruction/ > that we had for our target at that time (an IRIS-80, a french > machine derived from XDS-Sigma7). Fair enough. No further discussion needed, since it was OT in the first place, and only caused by my righteous irritation :-) at the destruction of Pascal by bad approximations. -- [mail]: Chuck F (cbfalconer at maineline dot net) [page]: <http://cbfalconer.home.att.net> Try the download section. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-22 21:11 ` CBFalconer 2008-07-23 8:40 ` Jean-Pierre Rosen @ 2008-07-26 11:13 ` Antoninus Twink 1 sibling, 0 replies; 61+ messages in thread From: Antoninus Twink @ 2008-07-26 11:13 UTC (permalink / raw) On 22 Jul 2008 at 21:11, CBFalconer wrote: > ISO Standard Pascal has no 'inc' instruction. Some non-standard > abortions do. However those abortions also omit critical portions > of the standard, such as f^ and the put and get functions. There > is more. By the "standards" you insist on holding the rest of the world to, you're way "off-topic". Try comp.lang.pascal or alt.bullshit.cbf-dribblings. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-22 10:45 ` Nick Keighley 2008-07-22 10:50 ` Richard 2008-07-22 11:20 ` Jean-Pierre Rosen @ 2008-07-22 12:05 ` Chris Dollin 2008-07-22 13:39 ` Walter Banks 3 siblings, 0 replies; 61+ messages in thread From: Chris Dollin @ 2008-07-22 12:05 UTC (permalink / raw) Nick Keighley wrote: > On 22 Jul, 09:39, Jean-Pierre Rosen <ro...@adalog.fr> wrote: >> Gautier a �crit : > > <snip> > >> > [this] comes from the time of >> > non-optimizing compilers for PC's - around 20 years ago. At that time a >> > i++ was faster than a i:= i + 1, sure. But it was long long time ago. >> > Never heard of GCC ?... >> >> When I started working on a (Pascal) compiler, this optimization was the >> first one I introduced in the compiler, because it was the easiest one >> to do. And it was 30 years ago... > > Pascal has a ++ operator? No, but it has an opportunity to optimise `i := i + 1;` to the same code as a C compiler might have compiled `i++` into. -- 'It changed the future .. and it changed us.' /Babylon 5/ Hewlett-Packard Limited registered office: Cain Road, Bracknell, registered no: 690597 England Berks RG12 1HN ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-22 10:45 ` Nick Keighley ` (2 preceding siblings ...) 2008-07-22 12:05 ` Chris Dollin @ 2008-07-22 13:39 ` Walter Banks 3 siblings, 0 replies; 61+ messages in thread From: Walter Banks @ 2008-07-22 13:39 UTC (permalink / raw) Nick Keighley wrote: > Pascal has a ++ operator? inc(x); w.. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-14 11:18 computer language used to program Mars Lander jhc0033 2008-07-14 11:21 ` jacob navia 2008-07-14 11:49 ` Nick Keighley @ 2008-07-14 15:31 ` george.priv 2008-07-14 15:38 ` Keith Thompson 2008-07-15 12:04 ` Stephen Leake 4 siblings, 0 replies; 61+ messages in thread From: george.priv @ 2008-07-14 15:31 UTC (permalink / raw) On Jul 14, 7:18 am, "jhc0...@gmail.com" <jhc0...@gmail.com> wrote: > Interesting article I came across on Slashdot: > > http://developers.slashdot.org/developers/08/07/10/213211.shtml > > They are using C at JPL to program Mars Lander and just about > everything now! Not Ada. Anyone got an explanation? I wonder also, do > they really mean C++ when they say C. In my experience, this is a > frequent, although disagreeable usage. As pointed out it was subset of C and the size of the software is relatively small by todays standards if it all fits in 128M (no VM AFAIK). The specifics of this project differs from earthly "life safety" type of applications. If probe software fails, watchdog will reboot it into the safe mode. There it will sit waiting the instructions/patches from home. Therefore, a critical part is a bootstrap and communication module. The rest is allowed to fail and can be fixed. George ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-14 11:18 computer language used to program Mars Lander jhc0033 ` (2 preceding siblings ...) 2008-07-14 15:31 ` george.priv @ 2008-07-14 15:38 ` Keith Thompson 2008-07-14 21:29 ` CBFalconer 2008-07-15 12:04 ` Stephen Leake 4 siblings, 1 reply; 61+ messages in thread From: Keith Thompson @ 2008-07-14 15:38 UTC (permalink / raw) "jhc0033@gmail.com" <jhc0033@gmail.com> writes: > Interesting article I came across on Slashdot: > > http://developers.slashdot.org/developers/08/07/10/213211.shtml > > They are using C at JPL to program Mars Lander and just about > everything now! Not Ada. Anyone got an explanation? I wonder also, do > they really mean C++ when they say C. In my experience, this is a > frequent, although disagreeable usage. This was cross-posted to comp.lang.ada and comp.lang.c. I suggest we all refuse to take the bait and *not* start a cross-language flame war. -- Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst> Nokia "We must do something. This is something. Therefore, we must do this." -- Antony Jay and Jonathan Lynn, "Yes Minister" ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-14 15:38 ` Keith Thompson @ 2008-07-14 21:29 ` CBFalconer 0 siblings, 0 replies; 61+ messages in thread From: CBFalconer @ 2008-07-14 21:29 UTC (permalink / raw) Keith Thompson wrote: > "jhc0033@gmail.com" <jhc0033@gmail.com> writes: > >> Interesting article I came across on Slashdot: >> >> http://developers.slashdot.org/developers/08/07/10/213211.shtml >> >> They are using C at JPL to program Mars Lander and just about >> everything now! Not Ada. Anyone got an explanation? I wonder >> also, do they really mean C++ when they say C. In my experience, >> this is a frequent, although disagreeable usage. > > This was cross-posted to comp.lang.ada and comp.lang.c. I > suggest we all refuse to take the bait and *not* start a > cross-language flame war. It has nothing to do with wars. It is simply an illustration that proves that it is _possible_ to generate accurate code with C. It is also possible with assembly language. However, doing so requires good programmers with plenty of experience. You can get equal quality from poorer programmers with less experience by using Ada. I leave it to you what you will get with experienced good programmers and Ada. -- [mail]: Chuck F (cbfalconer at maineline dot net) [page]: <http://cbfalconer.home.att.net> Try the download section. ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-14 11:18 computer language used to program Mars Lander jhc0033 ` (3 preceding siblings ...) 2008-07-14 15:38 ` Keith Thompson @ 2008-07-15 12:04 ` Stephen Leake 2008-07-15 13:55 ` Georg Bauhaus 2008-07-15 23:35 ` Phaedrus 4 siblings, 2 replies; 61+ messages in thread From: Stephen Leake @ 2008-07-15 12:04 UTC (permalink / raw) "jhc0033@gmail.com" <jhc0033@gmail.com> writes: > Interesting article I came across on Slashdot: > > http://developers.slashdot.org/developers/08/07/10/213211.shtml > > They are using C at JPL to program Mars Lander and just about > everything now! Not Ada. Anyone got an explanation? They are comfortable with their current tools, and simply refuse to consider others. I run into that attitude all the time. Even when they are considering adding tools like static analyzers, they won't consider changing languages. It's extremely frustrating! In the short run, sticking with what you know is safe. In the long run, it is a significant loss of productivity. JPL and many, many other places are sticking with the safe route. -- -- Stephe ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-15 12:04 ` Stephen Leake @ 2008-07-15 13:55 ` Georg Bauhaus 2008-07-15 23:35 ` Phaedrus 1 sibling, 0 replies; 61+ messages in thread From: Georg Bauhaus @ 2008-07-15 13:55 UTC (permalink / raw) Stephen Leake schrieb: > In the short run, sticking with what you know is safe. In the long > run, it is a significant loss of productivity. JPL and many, many > other places are sticking with the safe route. Leon Festinger (1957): A Theory of Congnitive Dissonance. -- Georg Bauhaus Y A Time Drain http://www.9toX.de ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-15 12:04 ` Stephen Leake 2008-07-15 13:55 ` Georg Bauhaus @ 2008-07-15 23:35 ` Phaedrus 2008-07-16 5:21 ` christoph.grein 1 sibling, 1 reply; 61+ messages in thread From: Phaedrus @ 2008-07-15 23:35 UTC (permalink / raw) "Stephen Leake" <Stephe.Leake@nasa.gov> wrote in message news:uvdz7uzeu.fsf@nasa.gov... > "jhc0033@gmail.com" <jhc0033@gmail.com> writes: > >> Interesting article I came across on Slashdot: >> >> http://developers.slashdot.org/developers/08/07/10/213211.shtml >> >> They are using C at JPL to program Mars Lander and just about >> everything now! Not Ada. Anyone got an explanation? > > They are comfortable with their current tools, and simply refuse to > consider others. > > I run into that attitude all the time. Even when they are considering > adding tools like static analyzers, they won't consider changing > languages. It's extremely frustrating! > > In the short run, sticking with what you know is safe. In the long > run, it is a significant loss of productivity. JPL and many, many > other places are sticking with the safe route. > > -- > -- Stephe Actually, JPL did try Ada for a few projects. In the late early '90s they got the contract from the Army to work on the All Source Analysis System (ASAS), a very large project. Also, unless my memory fails me they also did some (if not all) of the Cassini software in Ada, and I believe they did other projects in Ada, too. While Cassini (being a relatively small, well contained project) went well, ASAS was another thing altogether. The problem isn't that they won't try Ada, the problem is that when they did, they didn't get the results they wanted. Remember back when Ada was the buzzword to have on your resume? That was when they tried Ada, and some of the contractors they hired to "show them the way" weren't even sure how to spell Ada, much less get anything done in it. (A VERY high priced contractor on ASAS admitted to me that he had never even seen Ada code before being hired for his "expert" knowledge. Amazingly, they never caught on, even after he went on to greener pastures they were still raving about him!) Sadly, these blunders and others don't get remembered as "how NOT to manage a software project", they get filed under "Ada sucks". We need to convince them to give her another chance. --Brian ^ permalink raw reply [flat|nested] 61+ messages in thread
* Re: computer language used to program Mars Lander 2008-07-15 23:35 ` Phaedrus @ 2008-07-16 5:21 ` christoph.grein 0 siblings, 0 replies; 61+ messages in thread From: christoph.grein @ 2008-07-16 5:21 UTC (permalink / raw) On 16 Jul., 01:35, "Phaedrus" <phaedrus...@hotmail.com> wrote: > Sadly, these blunders and others don't get remembered as "how NOT to manage > a software project", they get filed under "Ada sucks". We need to convince > them to give her another chance. I remember a guy appearing at Ada Europe conference in Toulouse speaking about a project they started in Ada. They had no clear idea what to do, didn't really know the language, had no strategy, they really muddled along - and of course failed miserably. Then he continued with saying, OK, we redid the project now that we knew what and how to do, and we used C and it was a success. We will never again use Ada. (A fool with a good tool is still a fool.) ^ permalink raw reply [flat|nested] 61+ messages in thread
end of thread, other threads:[~2008-07-26 12:51 UTC | newest] Thread overview: 61+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2008-07-14 11:18 computer language used to program Mars Lander jhc0033 2008-07-14 11:21 ` jacob navia 2008-07-14 21:27 ` Maciej Sobczak 2008-07-14 11:49 ` Nick Keighley 2008-07-15 7:27 ` Maciej Sobczak 2008-07-16 6:02 ` jhc0033 2008-07-16 21:57 ` Brian 2008-07-23 14:43 ` Michael Oswald 2008-07-23 22:53 ` Larry Elmore 2008-07-24 6:59 ` jhc0033 2008-07-24 7:18 ` Stefan Scholl 2008-07-24 12:14 ` Grant Rettke 2008-07-24 7:39 ` John Thingstad 2008-07-24 7:51 ` jhc0033 2008-07-24 9:40 ` John Thingstad 2008-07-24 20:39 ` Brian 2008-07-25 6:10 ` jhc0033 2008-07-25 20:29 ` Brian 2008-07-26 3:03 ` jhc0033 2008-07-26 6:09 ` Brian 2008-07-24 8:40 ` pls.mrjm 2008-07-24 9:04 ` Pascal J. Bourguignon 2008-07-24 11:35 ` Michael Oswald 2008-07-24 12:15 ` Stefan Scholl 2008-07-24 12:36 ` Michael Oswald 2008-07-25 21:19 ` j.oke 2008-07-25 22:34 ` Adam Beneschan 2008-07-25 23:30 ` Joost Kremers 2008-07-26 12:41 ` j.oke 2008-07-26 12:51 ` j.oke 2008-07-17 21:56 ` Paul Hsieh 2008-07-17 22:30 ` Chris Thomasson 2008-07-17 23:03 ` Default User 2008-07-18 0:03 ` Chris Thomasson 2008-07-18 0:02 ` Gary Scott 2008-07-18 0:08 ` Chris Thomasson 2008-07-18 18:02 ` Colin Paul Gloster 2008-07-18 18:51 ` Dmitry A. Kazakov 2008-07-18 18:37 ` Pascal Obry 2008-07-18 19:45 ` Gautier 2008-07-18 20:26 ` jacob navia 2008-07-18 21:01 ` Georg Bauhaus 2008-07-18 21:14 ` Gary Scott 2008-07-18 20:45 ` Richard Tobin 2008-07-22 8:39 ` Jean-Pierre Rosen 2008-07-22 10:45 ` Nick Keighley 2008-07-22 10:50 ` Richard 2008-07-22 11:20 ` Jean-Pierre Rosen 2008-07-22 21:11 ` CBFalconer 2008-07-23 8:40 ` Jean-Pierre Rosen 2008-07-23 13:00 ` CBFalconer 2008-07-26 11:13 ` Antoninus Twink 2008-07-22 12:05 ` Chris Dollin 2008-07-22 13:39 ` Walter Banks 2008-07-14 15:31 ` george.priv 2008-07-14 15:38 ` Keith Thompson 2008-07-14 21:29 ` CBFalconer 2008-07-15 12:04 ` Stephen Leake 2008-07-15 13:55 ` Georg Bauhaus 2008-07-15 23:35 ` Phaedrus 2008-07-16 5:21 ` christoph.grein
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