In article
<·····················@twister01.bloor.is.net.cable.rogers.com>,
········@allstream.net wrote:
> Spirit has glitched. They hope to reset it.
>
> Anyone know how the software is built (language, RTOS, etc)?
>
> thanks
> pt
The flight software is all written in C running on vxWorks.
The ground software is a mishmash of C, C++, Fortran, Perl and Java (and
maybe a few other things.)
The other day in the hallway I heard a MER team member who had worked on
some of the C++ ground software say, "I wish we were using Lisp." I had
to leave the conversation at that point to avoid having a Howard Dean
moment.
E.
Erann Gat wrote:
> In article
> <·····················@twister01.bloor.is.net.cable.rogers.com>,
> ········@allstream.net wrote:
>
>
>>Spirit has glitched. They hope to reset it.
>>
>>Anyone know how the software is built (language, RTOS, etc)?
>>
>>thanks
>>pt
>
>
> The flight software is all written in C running on vxWorks.
>
> The ground software is a mishmash of C, C++, Fortran, Perl and Java (and
> maybe a few other things.)
>
> The other day in the hallway I heard a MER team member who had worked on
> some of the C++ ground software say, "I wish we were using Lisp." I had
> to leave the conversation at that point to avoid having a Howard Dean
> moment.
>
> E.
<OT>
I couldn't let this go by.
Dean was in a *very* loud room, with an uncertain sound system, trying
to rally the volunteers after a caucus whose results were not nearly
what they had either expected or hoped for.
I find it rather disturbing that virtually *all* media outlets (no
matter what their perceived biases might be) have spun this as a
meltdown. And, no matter what one's politics might be, exceedingly unfair.
OK, now back to our regularly scheduled programming....
</OT>
--ag
--
Artie Gold -- Austin, Texas
In article <··············@ID-219787.news.uni-berlin.de>, Artie Gold
<·········@austin.rr.com> wrote:
> Erann Gat wrote:
> > In article
> > <·····················@twister01.bloor.is.net.cable.rogers.com>,
> > ········@allstream.net wrote:
> >
> >
> >>Spirit has glitched. They hope to reset it.
> >>
> >>Anyone know how the software is built (language, RTOS, etc)?
> >>
> >>thanks
> >>pt
> >
> >
> > The flight software is all written in C running on vxWorks.
> >
> > The ground software is a mishmash of C, C++, Fortran, Perl and Java (and
> > maybe a few other things.)
> >
> > The other day in the hallway I heard a MER team member who had worked on
> > some of the C++ ground software say, "I wish we were using Lisp." I had
> > to leave the conversation at that point to avoid having a Howard Dean
> > moment.
> >
> > E.
> <OT>
> I couldn't let this go by.
>
> Dean was in a *very* loud room, with an uncertain sound system, trying
> to rally the volunteers after a caucus whose results were not nearly
> what they had either expected or hoped for.
>
> I find it rather disturbing that virtually *all* media outlets (no
> matter what their perceived biases might be) have spun this as a
> meltdown. And, no matter what one's politics might be, exceedingly unfair.
>
> OK, now back to our regularly scheduled programming....
> </OT>
>
> --ag
I don't disagree. What I meant by "having a Howard Dean moment" was
"making a loud emotional outburst that would be widely misunderstood and
end up doing irrepairable damage to my career."
E.
Erann Gat wrote:
>
> In article <··············@ID-219787.news.uni-berlin.de>, Artie Gold
> <·········@austin.rr.com> wrote:
>
> > Erann Gat wrote:
> > > In article
> > > <·····················@twister01.bloor.is.net.cable.rogers.com>,
> > > ········@allstream.net wrote:
> > >
> > >
> > >>Spirit has glitched. They hope to reset it.
> > >>
> > >>Anyone know how the software is built (language, RTOS, etc)?
> > >>
> > >>thanks
> > >>pt
> > >
> > >
> > > The flight software is all written in C running on vxWorks.
> > >
> > > The ground software is a mishmash of C, C++, Fortran, Perl and Java (and
> > > maybe a few other things.)
> > >
> > > The other day in the hallway I heard a MER team member who had worked on
> > > some of the C++ ground software say, "I wish we were using Lisp." I had
> > > to leave the conversation at that point to avoid having a Howard Dean
> > > moment.
Wow, that sounds like mindshare to me. Was that person one of the Known
Persuaded, or was that a breakthru for them? Did the other people in the
group say:
() Not Python?
() What is Lisp?
() Stop teasing Eran
() Other__________
Have you been around to their office to warn them that Lisp advocacy
will be the end of them?
kenny
--
http://www.tilton-technology.com/
---------------------------------------------------------------
"[If anyone really has healing powers,] I would like to call
them about my knees."
-- Tenzin Gyatso, the Fourteenth Dalai Lama
In article <·················@nyc.rr.com>, Kenny Tilton
<·······@nyc.rr.com> wrote:
> Erann Gat wrote:
> > The other day in the hallway I heard a MER team member who had worked on
> > some of the C++ ground software say, "I wish we were using Lisp." I had
> > to leave the conversation at that point to avoid having a Howard Dean
> > moment.
>
> Wow, that sounds like mindshare to me. Was that person one of the Known
> Persuaded, or was that a breakthru for them?
He was a known Lisper. I don't know if it would be fair to call him
"known persuaded." It definitely was not a case of a C++ programmer
having an epiphany.
> Did the other people in the group say:
>
> () Not Python?
> () What is Lisp?
> () Stop teasing Eran
> () Other__________
There was one other person involved in the conversation, and he was
definitely "known persuaded". He also made no response.
> Have you been around to their office to warn them that Lisp advocacy
> will be the end of them?
No. If I wanted to dissuade someone from using Lisp there are much more
effective tactics, like suggesting they do a google search on "lisp jobs"
and compare the results to "c++ jobs" and "perl jobs", or even "python
jobs".
Aren't you glad you asked?
E.
·········@jpl.nasa.gov (Erann Gat) writes:
> No. If I wanted to dissuade someone from using Lisp there are much more
> effective tactics, like suggesting they do a google search on "lisp jobs"
> and compare the results to "c++ jobs" and "perl jobs", or even "python
> jobs".
Googling on ``food service jobs'' gives you even more hits.
In article <············@ccs.neu.edu>, Joe Marshall <···@ccs.neu.edu> wrote:
> ·········@jpl.nasa.gov (Erann Gat) writes:
>
> > No. If I wanted to dissuade someone from using Lisp there are much more
> > effective tactics, like suggesting they do a google search on "lisp jobs"
> > and compare the results to "c++ jobs" and "perl jobs", or even "python
> > jobs".
>
> Googling on ``food service jobs'' gives you even more hits.
I couldn't decide between two responses to this, so I decided to post them
both and let you choose:
1. I've never heard of the "food service" programming language. Is it
new? Could you point me to a reference?
2. Googling on "steve jobs" gives you a lot of hits too. Your point
would be...?
E.
·········@jpl.nasa.gov (Erann Gat) writes:
> In article <············@ccs.neu.edu>, Joe Marshall <···@ccs.neu.edu> wrote:
>
>> ·········@jpl.nasa.gov (Erann Gat) writes:
>>
>> > No. If I wanted to dissuade someone from using Lisp there are much more
>> > effective tactics, like suggesting they do a google search on "lisp jobs"
>> > and compare the results to "c++ jobs" and "perl jobs", or even "python
>> > jobs".
>>
>> Googling on ``food service jobs'' gives you even more hits.
>
> I couldn't decide between two responses to this, so I decided to post them
> both and let you choose:
>
> 1. I've never heard of the "food service" programming language. Is it
> new? Could you point me to a reference?
It is the latest thing. It has some of the features from all these
languages: Java, Apple Script, Fromage, HotTea, Jam, and Korn Shell.
It's best for writing spaghetti code .... if you can stomach it.
> 2. Googling on "steve jobs" gives you a lot of hits too. Your point
> would be...?
Those that would be dissuaded from using a language simply by counting
Google hits might feel more fulfilled in the food service industry.
That is, if they cannot be Steve Jobs.
Erann Gat wrote:
>
> In article <············@ccs.neu.edu>, Joe Marshall <···@ccs.neu.edu> wrote:
>
> > ·········@jpl.nasa.gov (Erann Gat) writes:
> >
> > > No. If I wanted to dissuade someone from using Lisp there are much more
> > > effective tactics, like suggesting they do a google search on "lisp jobs"
> > > and compare the results to "c++ jobs" and "perl jobs", or even "python
> > > jobs".
> >
> > Googling on ``food service jobs'' gives you even more hits.
>
> I couldn't decide between two responses to this, so I decided to post them
> both and let you choose:
>
> 1. I've never heard of the "food service" programming language. Is it
> new? Could you point me to a reference?
>
> 2. Googling on "steve jobs" gives you a lot of hits too. Your point
> would be...?
Well before we veer too far off course, recall that this whole job
search thing arose because you responded with a non sequitor to my
comment about Lisp advocacy internally at NASA possibly doing damage to
ones internal rep. But your "jobs" segue does bring us back to the idea
that it is probably wiser to try to persuade your employer to use Lisp
than to wait for the great unwashed to start listing openings on Dice.
Gee, isn't NASA trying to learn how to learn after losing another
shuttle? How about a nice subtle note up the ladder pointing out that
NASA does not use the best technology possible out of unreasoned
prejudice? When they fire you, boom, front page of the Washington Post:
"NASA Never Learns".
kenny
--
clinisys, inc
http://www.tilton-technology.com/
---------------------------------------------------------------
"[If anyone really has healing powers,] I would like to call
them about my knees."
-- Tenzin Gyatso, the Fourteenth Dalai Lama
In article <················@nyc.rr.com>, Kenny Tilton
<·······@nyc.rr.com> wrote:
> Well before we veer too far off course, recall that this whole job
> search thing arose because you responded with a non sequitor to my
> comment about Lisp advocacy internally at NASA possibly doing damage to
> ones internal rep.
Let us take a moment to recall what you actually said:
> Have you been around to their office to warn them that Lisp advocacy
> will be the end of them?
That was not a comment, it was a question, and a
have-you-stopped-beating-your-wife-yet style question at that. Given our
history, I took it as a thinly veiled swipe at me because I do not measure
up to your standards of Lisp advocacy.
But if you really intended that to be a serious question/comment, then the
answer is, no, I have not warned them because 1) I do not wish to project
my own prejudices on other people and turn my pessimism in to a
self-fulfilling prophecy and 2) I'm pretty sure they already know.
> But your "jobs" segue does bring us back to the idea
> that it is probably wiser to try to persuade your employer to use Lisp
> than to wait for the great unwashed to start listing openings on Dice.
Agreed, but that is not always possible. An even better option is to
start your own company.
> Gee, isn't NASA trying to learn how to learn after losing another
> shuttle? How about a nice subtle note up the ladder pointing out that
> NASA does not use the best technology possible out of unreasoned
> prejudice? When they fire you, boom, front page of the Washington Post:
> "NASA Never Learns".
What makes you think that hasn't been tried?
E.
Joe Marshall wrote:
>
> ·········@jpl.nasa.gov (Erann Gat) writes:
>
> > No. If I wanted to dissuade someone from using Lisp there are much more
> > effective tactics, like suggesting they do a google search on "lisp jobs"
> > and compare the results to "c++ jobs" and "perl jobs", or even "python
> > jobs".
>
> Googling on ``food service jobs'' gives you even more hits.
'Nuff said. Joe, you are redeemed.
:)
kenny
--
clinisys, inc
http://www.tilton-technology.com/
---------------------------------------------------------------
"[If anyone really has healing powers,] I would like to call
them about my knees."
-- Tenzin Gyatso, the Fourteenth Dalai Lama
Erann Gat wrote:
>
> In article <·················@nyc.rr.com>, Kenny Tilton
> <·······@nyc.rr.com> wrote:
>
> > Erann Gat wrote:
>
> > > The other day in the hallway I heard a MER team member who had worked on
> > > some of the C++ ground software say, "I wish we were using Lisp." I had
> > > to leave the conversation at that point to avoid having a Howard Dean
> > > moment.
> >
> > Wow, that sounds like mindshare to me. Was that person one of the Known
> > Persuaded, or was that a breakthru for them?
>
> He was a known Lisper. I don't know if it would be fair to call him
> "known persuaded." It definitely was not a case of a C++ programmer
> having an epiphany.
>
> > Did the other people in the group say:
> >
> > () Not Python?
> > () What is Lisp?
> > () Stop teasing Eran
> > () Other__________
>
> There was one other person involved in the conversation, and he was
> definitely "known persuaded". He also made no response.
The good news being there are at least three Lispniks in da house. Why
don't you start an in-house Lisp social club? The Cells/Cello
Extravaganza leaves Broadway to go on The Road in early Feb for its
first gig in Boulder, and I'd be happy to entertain the troops at Nasa.
kenny
--
http://www.tilton-technology.com/
---------------------------------------------------------------
"[If anyone really has healing powers,] I would like to call
them about my knees."
-- Tenzin Gyatso, the Fourteenth Dalai Lama
In article <·················@nyc.rr.com>, Kenny Tilton
<·······@nyc.rr.com> wrote:
> The good news being there are at least three Lispniks in da house.
There are actually more than that. (But not a whole lot more.)
> Why don't you start an in-house Lisp social club?
You mean in addition to CRACL? Why do you think that would be a
worthwhile thing to do?
> The Cells/Cello
> Extravaganza leaves Broadway to go on The Road in early Feb for its
> first gig in Boulder, and I'd be happy to entertain the troops at Nasa.
If you you can pay your own way here I would be more than happy to arrange
for you to give a talk at JPL.
E.
·········@jpl.nasa.gov (Erann Gat) writes:
> In article <·················@nyc.rr.com>, Kenny Tilton
> <·······@nyc.rr.com> wrote:
>
> > The Cells/Cello Extravaganza leaves Broadway to go on The Road in
> > early Feb for its first gig in Boulder, and I'd be happy to
> > entertain the troops at Nasa.
>
> If you you can pay your own way here I would be more than happy to
> arrange for you to give a talk at JPL.
So, the next time you're going to send a robot up there, the Marsians
will be able to make sense of the UI and reboot the damn thing?
Regards,
--
Nils G�sche
"Don't ask for whom the <CTRL-G> tolls."
PGP key ID #xEEFBA4AF
···@cartan.de (Nils G�sche) writes:
> So, the next time you're going to send a robot up there, the Marsians
> will be able to make sense of the UI and reboot the damn thing?
If I understand correctly what I have read, Spirit rebooted itself 60
times over a period of a couple of days. Erann: any comments?
Paolo
--
Why Lisp? http://alu.cliki.net/RtL%20Highlight%20Film
In article <··············@plato.moon.paoloamoroso.it>, Paolo Amoroso
<·······@mclink.it> wrote:
> ···@cartan.de (Nils G�sche) writes:
>
> > So, the next time you're going to send a robot up there, the Marsians
> > will be able to make sense of the UI and reboot the damn thing?
>
> If I understand correctly what I have read, Spirit rebooted itself 60
> times over a period of a couple of days. Erann: any comments?
I don't have any particular inside track into current events since I'm not
on the MER team. I can give you a lot of the inside scoop about the
history of the project (like how the software was written) but when it
comes to what's going on day to day I have to read the papers like
everyone else.
E.
·········@jpl.nasa.gov (Erann Gat) writes:
> I don't have any particular inside track into current events since I'm not
> on the MER team. I can give you a lot of the inside scoop about the
> history of the project (like how the software was written) but when it
> comes to what's going on day to day I have to read the papers like
> everyone else.
It's no longer necessary. The Spirit resets have been mentioned in
official press releases. Thanks anyway,
Paolo
--
Why Lisp? http://alu.cliki.net/RtL%20Highlight%20Film
Paolo Amoroso wrote:
> ···@cartan.de (Nils G�sche) writes:
>
>
>>So, the next time you're going to send a robot up there, the Marsians
>>will be able to make sense of the UI and reboot the damn thing?
>
>
> If I understand correctly what I have read, Spirit rebooted itself 60
> times over a period of a couple of days. Erann: any comments?
Embedded systems like that usually have watchdog hardware/software. When the
machine crashes/freezes the watchdog reboots the system. This
probably indicates that there is a repeatable fault which has the system
continually resetting, the system boots, runs for a while, crashes or
detects a problem (maybe no communication with Earth), etc, etc, etc
Wade
Paolo Amoroso <·······@mclink.it> writes:
> ···@cartan.de (Nils G�sche) writes:
>
> > So, the next time you're going to send a robot up there, the Marsians
> > will be able to make sense of the UI and reboot the damn thing?
>
> If I understand correctly what I have read, Spirit rebooted itself 60
> times over a period of a couple of days. Erann: any comments?
I think Erann mentioned they were using vxWorks, so I am not
surprised...
Regards,
--
Nils G�sche
"Don't ask for whom the <CTRL-G> tolls."
PGP key ID #xEEFBA4AF
Erann Gat wrote:
>
> In article <·················@nyc.rr.com>, Kenny Tilton
> <·······@nyc.rr.com> wrote:
>
> > The good news being there are at least three Lispniks in da house.
>
> There are actually more than that. (But not a whole lot more.)
Awesome.
>
> > Why don't you start an in-house Lisp social club?
>
> You mean in addition to CRACL? Why do you think that would be a
> worthwhile thing to do?
To better infect JPL. Lisp is a contagious, um, cure, so propinquity
counts.
>
> > The Cells/Cello
> > Extravaganza leaves Broadway to go on The Road in early Feb for its
> > first gig in Boulder, and I'd be happy to entertain the troops at Nasa.
>
> If you you can pay your own way here I would be more than happy to arrange
> for you to give a talk at JPL.
I leave Denver 2/10 in the PM. Don't know if I can change the flights.
If so, how about 2/11? Could non-JPL CRACLers attend? btw, the emphasis
would be on Cells (which could be implemented in C++), tho of course it
is hard not to digress into Lisp worship when discussing programming at
all.
kenny
--
clinisys, inc
http://www.tilton-technology.com/
---------------------------------------------------------------
"[If anyone really has healing powers,] I would like to call
them about my knees."
-- Tenzin Gyatso, the Fourteenth Dalai Lama
In article <················@nyc.rr.com>, Kenny Tilton
<·······@nyc.rr.com> wrote:
> > > Why don't you start an in-house Lisp social club?
> >
> > You mean in addition to CRACL? Why do you think that would be a
> > worthwhile thing to do?
>
> To better infect JPL. Lisp is a contagious, um, cure, so propinquity
> counts.
But the Lispers are all already, er, infected, and JPL (to say nothing of
the world at large) has developed some pretty effective antibodies.
> > > The Cells/Cello
> > > Extravaganza leaves Broadway to go on The Road in early Feb for its
> > > first gig in Boulder, and I'd be happy to entertain the troops at Nasa.
> >
> > If you you can pay your own way here I would be more than happy to arrange
> > for you to give a talk at JPL.
>
> I leave Denver 2/10 in the PM. Don't know if I can change the flights.
> If so, how about 2/11?
Should be fine. Let me double check the conference room schedule on Monday.
> Could non-JPL CRACLers attend?
Probably not. Security is pretty hairy nowadays. But maybe we could set
something up outside JPL in the evening. (That would work better if you
could arrange to be here over a weekend. CRACL meets on Sundays.)
We should probably work on the logistics via email rather than usenet.
> btw, the emphasis
> would be on Cells (which could be implemented in C++), tho of course it
> is hard not to digress into Lisp worship when discussing programming at
> all.
Seems like a bit of a cop-out to me considering the hard time you've given
me for shying away from direct Lisp advocacy. But you can talk about
whatever you like.
E.
From: Kenny Tilton
Subject: Cells In Space! [was Re: Mars Rover failure]
Date:
Message-ID: <401216F8.9EF964A2@nyc.rr.com>
Erann Gat wrote:
>
> In article <················@nyc.rr.com>, Kenny Tilton
> <·······@nyc.rr.com> wrote:
>
> > To better infect JPL. Lisp is a contagious, um, cure, so propinquity
> > counts.
>
> But the Lispers are all already, er, infected, and JPL (to say nothing of
> the world at large) has developed some pretty effective antibodies.
That's part of why I would not go at it head-on at JPL. That just
triggers the immune system. But if I talk about an important software
paradigm and someone is impressed, when they ask "why use Lisp instead
of C++" they are actually asking, not looking for a fight.
> We should probably work on the logistics via email rather than usenet.
check.
> > btw, the emphasis
> > would be on Cells (which could be implemented in C++), tho of course it
> > is hard not to digress into Lisp worship when discussing programming at
> > all.
>
> Seems like a bit of a cop-out to me considering the hard time you've given
> me for shying away from direct Lisp advocacy.
Thx so much for characterizing it as cowardice, but my impetus was
respect for the audience.
My honest guess (CMIIAW) is that Cells would be more novel to the
audience than Lisp, not just because there are some Lispniks at JPL who
like you may have flogged that horse, but also because things like the
REPL are old hat to anyone who cut their teeth on Basic (or are using
Perl or Python now).
The talk would also appeal to a wider audience, because the paradigm is
language neutral. It looks better in Lisp, but everything does. If they
end up adopting the paradigm, at least their software is that much
better.
But to explore the paradigm, well, they have to do a little Lisp to
decide if they want to put a team on doing the C++ version of Cells. So
then Lisp gets its foot in the door. And maybe during the C++ port a
little light goes on.
Call the talk "Why You Should Be Using Lisp" and the defenses go up. It
is a poor advocate who begins by alienating the jury, methinks. The good
news is I have a Trojan horse to cell them instead.
kenny
--
http://www.tilton-technology.com/
---------------------------------------------------------------
"[If anyone really has healing powers,] I would like to call
them about my knees."
-- Tenzin Gyatso, the Fourteenth Dalai Lama
In article <·················@nyc.rr.com>, Kenny Tilton
<·······@nyc.rr.com> wrote:
> Erann Gat wrote:
> >
> > In article <················@nyc.rr.com>, Kenny Tilton
> > <·······@nyc.rr.com> wrote:
> >
> > > To better infect JPL. Lisp is a contagious, um, cure, so propinquity
> > > counts.
> >
> > But the Lispers are all already, er, infected, and JPL (to say nothing of
> > the world at large) has developed some pretty effective antibodies.
>
> That's part of why I would not go at it head-on at JPL. That just
> triggers the immune system. But if I talk about an important software
> paradigm and someone is impressed, when they ask "why use Lisp instead
> of C++" they are actually asking, not looking for a fight.
The reaction historically has been closer to, "That's really great stuff.
Too bad it's written in Lisp. Can you rewrite it in C++?"
> > > btw, the emphasis
> > > would be on Cells (which could be implemented in C++), tho of course it
> > > is hard not to digress into Lisp worship when discussing programming at
> > > all.
> >
> > Seems like a bit of a cop-out to me considering the hard time you've given
> > me for shying away from direct Lisp advocacy.
>
> Thx so much for characterizing it as cowardice, but my impetus was
> respect for the audience.
You have a funny way of showing respect some times, but that's neither
here nor there.
> Call the talk "Why You Should Be Using Lisp" and the defenses go up.
I vaguely recall hearing you advocating a direct approach in the past, but
that is likewise neither here nor there. Let us take the current
situation and move on from here: I think the above observation is exactly
right, and I'm looking forward to hearing your talk.
E.
From: Kenny Tilton
Subject: Re: Cells In Space! [was Re: Mars Rover failure]
Date:
Message-ID: <40129642.A8E7AC2B@nyc.rr.com>
I should have added that if I am wrong and "Why I love Lisp" would not
just make people roll their eyes, I have a fun talk in which I reinvent
Cells (in primitive form) over the keyboard while you watch. This
manages to touch on macros, special variables, anonymous functions,
CLOS, and of course RAD all in very short order, and everything gets
pulled in for a reason (ie, it's all nicely motivated, not just
gee-whizzing over language features).
How much time do I have?
kenny
--
clinisys, inc
http://www.tilton-technology.com/
---------------------------------------------------------------
"[If anyone really has healing powers,] I would like to call
them about my knees."
-- Tenzin Gyatso, the Fourteenth Dalai Lama
In article <·················@nyc.rr.com>, Kenny Tilton
<·······@nyc.rr.com> wrote:
> I should have added that if I am wrong and "Why I love Lisp" would not
> just make people roll their eyes,
I think if you gave a talk that was advertised as "Why I love Lisp" then
very few people would show up, and none of the people who showed up would
matter. But I could be wrong. Maybe if you tried it you'd have better
luck than I've had.
> I have a fun talk in which I reinvent
> Cells (in primitive form) over the keyboard while you watch. This
> manages to touch on macros, special variables, anonymous functions,
> CLOS, and of course RAD all in very short order, and everything gets
> pulled in for a reason (ie, it's all nicely motivated, not just
> gee-whizzing over language features).
Sounds very cool, but again I don't think anyone who matters will care.
The problem is not the people don't know what Lisp can do. But that's
just my opinion. YMMV.
I think your initial instincts were correct, and taking a stealth approach
by talking (ostensibly at least) about Cells is most likely to be
productive.
>
> How much time do I have?
>
At JPL one hour. CRACL meetings are very informal and unstructured, and
typically last 3-4 beers^h^h^h^h^h hours. :-)
E.
From: Kenny Tilton
Subject: Re: Cells In Space! [was Re: Mars Rover failure]
Date:
Message-ID: <40135C2B.3268F7B1@nyc.rr.com>
Erann Gat wrote:
> I think your initial instincts were correct, and taking a stealth approach
> by talking (ostensibly at least) about Cells is most likely to be
> productive.
Cells it is. I wonder how many folks at JPL are aware that space
telescope operations are scheduled by a Cells work-alike called COSI
(and Lisp). That should make them sit up and take notice.
And come to think of it, Garnet was cast adrift to do a C++ port. Does
that mean there is a C++ KR floating around out there somewhere? IIRC,
Amulet has also been abandoned.
kenny
--
clinisys, inc
http://www.tilton-technology.com/
---------------------------------------------------------------
"[If anyone really has healing powers,] I would like to call
them about my knees."
-- Tenzin Gyatso, the Fourteenth Dalai Lama
Kenny Tilton <·······@nyc.rr.com> writes:
> Erann Gat wrote:
>
> > I think your initial instincts were correct, and taking a stealth approach
> > by talking (ostensibly at least) about Cells is most likely to be
> > productive.
>
> Cells it is. I wonder how many folks at JPL are aware that space
> telescope operations are scheduled by a Cells work-alike called COSI
> (and Lisp). That should make them sit up and take notice.
>
> And come to think of it, Garnet was cast adrift to do a C++ port. Does
> that mean there is a C++ KR floating around out there somewhere?
Yep, complete with a prototype-inheritance object system and
constraints and everything. It looks significantly more aweful to
use, but that's not surprising. The relevant part of the tutorial is
here:
http://www-2.cs.cmu.edu/afs/cs/project/amulet/amulet3/manual/tutorial_chapter.html#1010269
> IIRC, Amulet has also been abandoned.
They lost their gov't funding two years after Garnet support stopped
(imagine if they hadn't wasted those man-years on the Amulet adventure
:-P). A group of Amulet users tried to maintain the code base, but
that seems to have petered out by 2000. Amusingly enough, Garnet's
probably more alive, due to it's having been stable when it was
abandoned, so there wasn't all that much community work needed on
basic stuff. That said, the last 4 years haven't been kind to its
look-and-feel. It looked a little old in 2000 -- when I recently
pulled a Garnet window up on my OS X box, I laughed out loud from the
contrast.
--
/|_ .-----------------------.
,' .\ / | No to Imperialist war |
,--' _,' | Wage class war! |
/ / `-----------------------'
( -. |
| ) |
(`-. '--.)
`. )----'
In article <·················@nyc.rr.com>, Kenny Tilton
<·······@nyc.rr.com> wrote:
> Erann Gat wrote:
>
> > I think your initial instincts were correct, and taking a stealth approach
> > by talking (ostensibly at least) about Cells is most likely to be
> > productive.
>
> Cells it is. I wonder how many folks at JPL are aware that space
> telescope operations are scheduled by a Cells work-alike called COSI
> (and Lisp).
I think most people are vaguely aware that there are some Lisp legacy
applications floating around. They probably attribute this to not have
enough funding to do the right thing and port them to C++.
> That should make them sit up and take notice.
I wouldn't bet my life savings on it. There's no shortage of Lisp success
stories around here. I doubt one more will make the difference.
E.
From: Kenny Tilton
Subject: Re: Cells In Space! [was Re: Mars Rover failure]
Date:
Message-ID: <4014A06B.CB3B4033@nyc.rr.com>
Erann Gat wrote:
>
> In article <·················@nyc.rr.com>, Kenny Tilton
> <·······@nyc.rr.com> wrote:
>
> > Erann Gat wrote:
> >
> > > I think your initial instincts were correct, and taking a stealth approach
> > > by talking (ostensibly at least) about Cells is most likely to be
> > > productive.
> >
> > Cells it is. I wonder how many folks at JPL are aware that space
> > telescope operations are scheduled by a Cells work-alike called COSI
> > (and Lisp).
>
> I think most people are vaguely aware that there are some Lisp legacy
> applications floating around. They probably attribute this to not have
> enough funding to do the right thing and port them to C++.
>
> > That should make them sit up and take notice.
>
> I wouldn't bet my life savings on it. There's no shortage of Lisp success
> stories around here. I doubt one more will make the difference.
I was talking about the idea of driving an application via linear
dataflow constraints (like Cells). It ain't just a PhD paper, it's in
production.
And C++, in the form of the KR port to Amulet. I got 'em surrounded.
kt
--
clinisys, inc
http://www.tilton-technology.com/
---------------------------------------------------------------
"[If anyone really has healing powers,] I would like to call
them about my knees."
-- Tenzin Gyatso, the Fourteenth Dalai Lama
·········@jpl.nasa.gov (Erann Gat) writes:
> The reaction historically has been closer to, "That's really great stuff.
> Too bad it's written in Lisp. Can you rewrite it in C++?"
Or in best cases:
"Too bad it's written in Lisp. Can you rewrite it in Objective-C?"
(NeXTSTEP Interface Builder)
It might be (morbidly) interesting to establish a list...
--
__Pascal_Bourguignon__ http://www.informatimago.com/
There is no worse tyranny than to force a man to pay for what he doesn't
want merely because you think it would be good for him.--Robert Heinlein
http://www.theadvocates.org/
·········@jpl.nasa.gov (Erann Gat) wrote in message news:<··························@k-137-79-50-101.jpl.nasa.gov>...
> In article
> <·····················@twister01.bloor.is.net.cable.rogers.com>,
> ········@allstream.net wrote:
>
> > Spirit has glitched. They hope to reset it.
> >
> > Anyone know how the software is built (language, RTOS, etc)?
> >
> > thanks
> > pt
>
> The flight software is all written in C running on vxWorks.
Most of the Stereo Vision and Rover Navigation Software (70k or so
lines) is written in C++. There is some C and assembler code for
certain types of optimization.
This document's a little old, but relavent:
http://robotics.jpl.nasa.gov/people/mwm/visnavsw/aero.pdf
Patrick Olguin
In article <···························@posting.google.com>,
···········@yahoo.com (Patrick Olguin) wrote:
> ·········@jpl.nasa.gov (Erann Gat) wrote in message
news:<··························@k-137-79-50-101.jpl.nasa.gov>...
> > In article
> > <·····················@twister01.bloor.is.net.cable.rogers.com>,
> > ········@allstream.net wrote:
> >
> > > Spirit has glitched. They hope to reset it.
> > >
> > > Anyone know how the software is built (language, RTOS, etc)?
> > >
> > > thanks
> > > pt
> >
> > The flight software is all written in C running on vxWorks.
>
> Most of the Stereo Vision and Rover Navigation Software (70k or so
> lines) is written in C++.
Ah, right.
> This document's a little old, but relavent:
> http://robotics.jpl.nasa.gov/people/mwm/visnavsw/aero.pdf
Actually, to be strictly correct, the flight code is heavily modified from
the research code, and it's written in a restricted subset of C++. I
don't know the details of the restrictions, but for example they don't use
exceptions or namespaces (which is causing me considerable grief at the
moment).
E.
"Paul Tarvydas" <········@attcanada.ca> wrote in message
··························@twister01.bloor.is.net.cable.rogers.com...
> Spirit has glitched. They hope to reset it.
>
> Anyone know how the software is built (language, RTOS, etc)?
No doubt is was built with painstaking care, but by fallible humans.
Regards,
Will Hartung
(·····@msoft.com)
Will Hartung wrote:
> "Paul Tarvydas" <········@attcanada.ca> wrote in message
> ··························@twister01.bloor.is.net.cable.rogers.com...
>> Spirit has glitched. They hope to reset it.
>>
>> Anyone know how the software is built (language, RTOS, etc)?
>
> No doubt is was built with painstaking care, but by fallible humans.
One of my .sigs:
--
Cheers, www.indiegamedesign.com
Brandon Van Every Seattle, WA
"We live in a world of very bright people building
crappy software with total shit for tools and process."
- Ed Mckenzie
* Paul Tarvydas
| Spirit has glitched. They hope to reset it.
Maybe they have to send up a three-fingered robot to reboot it?
Or perhaps this is proof there is life on Mars. It just eats robots.
--
Erik Naggum | Oslo, Norway
Act from reason, and failure makes you rethink and study harder.
Act from faith, and failure makes you blame someone and push harder.
Erik Naggum wrote:
> * Paul Tarvydas
> | Spirit has glitched. They hope to reset it.
>
> Maybe they have to send up a three-fingered robot to reboot it?
>
> Or perhaps this is proof there is life on Mars. It just eats robots.
>
Or, perhaps, Marvin is really there and they don't want us to know?
[Oops, gotta go. Black helicopter about to land on roof. Need tinfoil to
line hat.]
:-)
--ag
--
Artie Gold -- Austin, Texas
Erik Naggum <····@naggum.no> writes:
> Or perhaps this is proof there is life on Mars. It just eats robots.
sorry to disappoint you ;-), but a press release stating that Spirit
is alive and transmitting just appeared on the NASA site.
(http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20040123a.html)
--
(espen)
Espen Vestre wrote:
> Erik Naggum <····@naggum.no> writes:
>
>
>> Or perhaps this is proof there is life on Mars. It just eats robots.
>
>
> sorry to disappoint you ;-), but a press release stating that Spirit
> is alive and transmitting just appeared on the NASA site.
>
> (http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20040123a.html)
Phew.
I guess that was a *not* a helicopter. Just a grackle. <g>
--ag
--
Artie Gold -- Austin, Texas
"Erik Naggum" <····@naggum.no> wrote:
> * Paul Tarvydas
> | Spirit has glitched. They hope to reset it.
>
> Maybe they have to send up a three-fingered robot to reboot it?
>
> Or perhaps this is proof there is life on Mars. It just eats robots.
There's a much simpler explanation. President George W. Bush recently
announced a plan to resume manned space exploration, with the Moon and Mars
as targets. A week or so later, the latest robot to land on Mars breaks
down, and humans millions of miles away at NASA on Earth are virtually
helpless to deal with it.
If only we had a man on Mars! Suddenly, Bush's brash plan, which looked so
silly a week ago, starts to look rather prescient, perhaps even visionary.
Coincidence? I think not!
Of course, Bush couldn't have simply instructed NASA to botch the latest
Mars probe. An instruction like that couldn't be kept secret. That's where
his dad, the ex-President - but more importantly, the ex-CIA director -
comes in. CIA sleepers within NASA, whose last task involved deliberately
sowing confusion about metric vs. imperial units of measure, were activated
once again. Due to an obscure jurisdictional loophole, the prohibition
against domestic activity by the CIA doesn't apply in the case of NASA,
which operates on other planets.
It wouldn't have taken much. Given that the rover's software is written in
C and C++, sabotaging it must have been child's play. In fact, the original
decision to use C may have been driven by these same shadowy forces...
The end result is that, having already bolstered his father's legacy by
cutting taxes for the rich, and ousting and capturing Saddam Hussein, the
junior Bush is now homing in on his father's most elusive unachieved goal:
"the vision thing". His daddy must be proud!
Anton
Anton van Straaten wrote:
> If only we had a man on Mars! Suddenly, Bush's brash plan, which looked so
> silly a week ago, starts to look rather prescient, perhaps even visionary.
> Coincidence? I think not!
You're right. You think -- not.
Paul
* Anton van Straaten wrote:
> There's a much simpler explanation. President George W. Bush recently
> announced a plan to resume manned space exploration, with the Moon and Mars
> as targets. A week or so later, the latest robot to land on Mars breaks
> down, and humans millions of miles away at NASA on Earth are virtually
> helpless to deal with it.
I prefer the fundamentalist viewpoint. They (the elusive `they' who
for these purposes are the religious fundamentalists - pick your
religion, we have a wide selection available - who run America) are
dead worried that Mars missions might discover other life, or the
traces of it. That would be bad, of course, so a little judicious
sabotage has left it crippled.
The `man on Mars' thing is just another aspect of course: spending
billions on (failing to) get a man (of course a *man*: women belong in
the home) to Mars is about the best way of making sure that no useful
science gets done. I mean, they've canned Hubble already.
Unfortunately, despite the crowing of Lisp people, I think the people
who write the SW for these things do actually know what they're doing,
and I bet they'll get it fixed if it's not some catastrophic HW
failure.
--tim
"Anton van Straaten" <·····@appsolutions.com> wrote in message news:<····················@newsread1.news.atl.earthlink.net>...
> An instruction like that couldn't be kept secret. That's where
> his dad, the ex-President - but more importantly, the ex-CIA director -
> comes in. CIA sleepers within NASA, whose last task involved deliberately
> sowing confusion about metric vs. imperial units of measure, were activated
> once again. Due to an obscure jurisdictional loophole, the prohibition
> against domestic activity by the CIA doesn't apply in the case of NASA,
> which operates on other planets.
Which dovetails perfectly with the fact that ALCOA was one of the
largest contributors to the Bush campaign - they stand to profit
handsomely when every member of the armed forces, NASA, CIA, and NSA
staffs must wear a Thermo-Irradiative-Nuclear-Fission-Obstructing-Infra-Luninescent-Hard-Aluminum-Top
(better known by its DOD acronym, TINFOIL-HAT) for protection from the
Martian Mind Ray!
ATF agents will have to buy their own though, since they screwed up
Waco so badly.
;^)
"Anton van Straaten" <·····@appsolutions.com> wrote in message
·························@newsread1.news.atl.earthlink.net...
> "Erik Naggum" <····@naggum.no> wrote:
> > * Paul Tarvydas
> > | Spirit has glitched. They hope to reset it.
> >
> > Maybe they have to send up a three-fingered robot to reboot it?
> >
> > Or perhaps this is proof there is life on Mars. It just eats robots.
>
> There's a much simpler explanation. President George W. Bush recently
> announced a plan to resume manned space exploration, with the Moon and
Mars
> as targets. A week or so later, the latest robot to land on Mars breaks
> down, and humans millions of miles away at NASA on Earth are virtually
> helpless to deal with it.
>
> If only we had a man on Mars! Suddenly, Bush's brash plan, which looked
so
> silly a week ago, starts to look rather prescient, perhaps even visionary.
> Coincidence? I think not!
>
> Of course, Bush couldn't have simply instructed NASA to botch the latest
> Mars probe. An instruction like that couldn't be kept secret. That's
where
> his dad, the ex-President - but more importantly, the ex-CIA director -
> comes in. CIA sleepers within NASA, whose last task involved deliberately
> sowing confusion about metric vs. imperial units of measure, were
activated
> once again. Due to an obscure jurisdictional loophole, the prohibition
> against domestic activity by the CIA doesn't apply in the case of NASA,
> which operates on other planets.
>
I don't think your theory of sabotaging the Mars Rover will make it
easier to get congress to spend billions of dollars on NASA spacecraft with
people on board
sc
Paul Tarvydas <········@attcanada.ca> writes:
> Spirit has glitched. They hope to reset it.
>
> Anyone know how the software is built (language, RTOS, etc)?
You haven't asked about hardware, but I think it's also
interesting. From the "Mars Exploration Rover Landings" press kit:
The computer in each Mars Exploration Rover runs with a 32-bit Rad
6000 microprocessor, a radiation-hardened version of the PowerPC
chip used in some models of Macintosh computers, operating at a
speed of 20 million instructions per second. Onboard memory includes
128 megabytes of random access memory, augmented by 256 megabytes of
flash memory and smaller amounts of other non-volatile memory, which
allows the system to retain data even without power.
Paolo
--
Why Lisp? http://alu.cliki.net/RtL%20Highlight%20Film
http://space.com/missionlaunches/spirit_relay_040124.html
"There is a growing feeling here that the robot may have been taxed too much
that is, too many "do this, do that" instructions were sent. That
multi-tasking could have sparked the problem, according to sources here.
Prior to its troubles on Mars, Spirit was being put through its paces --
doing things that were not tested with as much vigor here at JPL before
being launched.
Spirit does not have a huge track record of testing, a source said, for fear
of damaging the robot and not meeting an unforgiving launch window."
pt
Paul Tarvydas <········@attcanada.ca> writes:
> http://space.com/missionlaunches/spirit_relay_040124.html
>
> "There is a growing feeling here that the robot may have been taxed
> too much that is, too many "do this, do that" instructions were
> sent. That multi-tasking could have sparked the problem, according
> to sources here.
>
> Prior to its troubles on Mars, Spirit was being put through its
> paces -- doing things that were not tested with as much vigor here
> at JPL before being launched.
>
> Spirit does not have a huge track record of testing, a source said,
> for fear of damaging the robot and not meeting an unforgiving launch
> window."
Ouch.
This leads me to think the problem is along lines indicated by the
"Peter Principle / Parkinson's Law" type of thinking.
--
Fred Gilham ······@csl.sri.com
I can't escape the sensation that I have already been thinking in Lisp
all my programming career, but forcing the ideas into the constraints
of bad languages, which explode those ideas into a bewildering array
of details, most of which are workarounds for the language.
--Kaz Kylheku
Paul Tarvydas <········@attcanada.ca> writes:
> http://space.com/missionlaunches/spirit_relay_040124.html
>
> Spirit does not have a huge track record of testing, a source said, for fear
> of damaging the robot ...
Much better the idea of pushing its limits after dropping it out of
orbit and bouncing it across the ground where it couldn't possibly be
repaired.
--
~jrm
Joe Marshall <·············@comcast.net> writes:
> Paul Tarvydas <········@attcanada.ca> writes:
>
> > http://space.com/missionlaunches/spirit_relay_040124.html
> >
> > Spirit does not have a huge track record of testing, a source said, for fear
> > of damaging the robot ...
>
> Much better the idea of pushing its limits after dropping it out of
> orbit and bouncing it across the ground where it couldn't possibly be
> repaired.
For the time (it's expected to work a couple of months), and for the
accelleration, this can be easily tested on Earth. You don't even need
a rocket, just drop it from a plane over a desert and let it work for
a couple of month of testing.
For the temperature range and atmosphere, this can also be tested
intensively, only not necessarily at the same time, and if not for as
much time.
I've got the impression they did not test it a lot on Earth though...
--
__Pascal_Bourguignon__ http://www.informatimago.com/
There is no worse tyranny than to force a man to pay for what he doesn't
want merely because you think it would be good for him.--Robert Heinlein
http://www.theadvocates.org/
In article <··············@thalassa.informatimago.com>, Pascal Bourguignon
<····@thalassa.informatimago.com> wrote:
> I've got the impression they did not test it a lot on Earth though...
Launch windows present absolutely hard deadlines, and MER was done on an
incredibly tight schedule. Had it been an option I suspect the MER team
would have happily offered up a substantial colleciton of left gonads and
firstborn children for more time to test.
E.
·········@jpl.nasa.gov (Erann Gat) writes:
> In article <··············@thalassa.informatimago.com>, Pascal Bourguignon
> <····@thalassa.informatimago.com> wrote:
>
> > I've got the impression they did not test it a lot on Earth though...
>
> Launch windows present absolutely hard deadlines, and MER was done on an
> incredibly tight schedule. Had it been an option I suspect the MER team
> would have happily offered up a substantial colleciton of left gonads and
> firstborn children for more time to test.
>
> E.
I've got the impression that between Earth and Mars, the periodicity
of the launch window is about yearly.
But I assume that if they had delayed launch one year, they would have
lost their budget!
--
__Pascal_Bourguignon__ http://www.informatimago.com/
There is no worse tyranny than to force a man to pay for what he doesn't
want merely because you think it would be good for him.--Robert Heinlein
http://www.theadvocates.org/
In article <··············@thalassa.informatimago.com>, Pascal Bourguignon
<····@thalassa.informatimago.com> wrote:
> ·········@jpl.nasa.gov (Erann Gat) writes:
>
> > In article <··············@thalassa.informatimago.com>, Pascal Bourguignon
> > <····@thalassa.informatimago.com> wrote:
> >
> > > I've got the impression they did not test it a lot on Earth though...
> >
> > Launch windows present absolutely hard deadlines, and MER was done on an
> > incredibly tight schedule. Had it been an option I suspect the MER team
> > would have happily offered up a substantial colleciton of left gonads and
> > firstborn children for more time to test.
> >
> > E.
>
> I've got the impression that between Earth and Mars, the periodicity
> of the launch window is about yearly.
For Mars it's once every two years.
> But I assume that if they had delayed launch one year, they would have
> lost their budget!
It's more complicated than that. Getting a spacecraft launched is an
incredibly complicated logistical dance. Also, spacecraft don't have a
very long shelf life. (The failure of the Galileo high gain antenna was
probably due to being in storage too long after the Challenger
explosion). Postponing a launch by two years is not very different from
starting over from the beginning, especially when you're talking about a
mission that was only three years from start to launch as MER was.
E.
·········@jpl.nasa.gov (Erann Gat) writes:
> Also, spacecraft don't have a very long shelf life. (The failure of
> the Galileo high gain antenna was probably due to being in storage
> too long after the Challenger explosion).
What rots? (or, could you point to the right place to look? I
can't find the correct combination of terms for Google.)
--
Chris Jeris ······@oinvzer.net Apply (1 6 2 4)(3 7) to domain to reply.
In article <··················@hsph.harvard.edu>, Christopher Jeris
<······@oinvzer.net> wrote:
> ·········@jpl.nasa.gov (Erann Gat) writes:
> > Also, spacecraft don't have a very long shelf life. (The failure of
> > the Galileo high gain antenna was probably due to being in storage
> > too long after the Challenger explosion).
>
> What rots? (or, could you point to the right place to look? I
> can't find the correct combination of terms for Google.)
Lubrication mainly. (It doesn't rot, it outgasses. I think. This is at
the hairy limits of my knowledge. If you really want to know details I
can try to hunt down someone who actually knows and ask them.)
But the main problem is logistics. Launch preparations take months and
involve hundreds (if not thousands) of people. The spacecraft has to be
tested. Then it has to be packaged for shipment. Then it has to be
shipped. Then it has to be unpacked. Then it has to be tested again to
find out if anything broke during shipment. Then whatever broke has to be
fixed. Then it has to be mated to the launch vehicle. Then it has to be
tested again to find out if anything broke during the mating process.
Etc. etc. etc. All the arrangements have to be made well in advance. If
the delivery truck shows up at the Cape and there's no one there ready to
receive it because everyone happens to be busy doing something else that
day you can't just leave it on the front doorstep.
Postponing all that by two years is possible, but it's very, very
expensive. Just *storing* a spacecraft for two years is expensive (and
risky). You can't just shove it into the janitor's closet. And any
change to the schedule has ripple effects throughout the entire space
program, because the facility that you were going to use to build
spacecraft Y is now unavailable because it has to be used to store
spaceccraft X.
Are you beginning to see why postponing a launch because of software is
highly frowned upon?
E.
·········@jpl.nasa.gov (Erann Gat) writes:
> But the main problem is logistics. Launch preparations take months and
> involve hundreds (if not thousands) of people. The spacecraft has to be
> tested. Then it has to be packaged for shipment. Then it has to be
> shipped. Then it has to be unpacked. Then it has to be tested again to
> find out if anything broke during shipment. Then whatever broke has to be
> fixed. Then it has to be mated to the launch vehicle. Then it has to be
> tested again to find out if anything broke during the mating process.
> Etc. etc. etc. All the arrangements have to be made well in advance. If
> the delivery truck shows up at the Cape and there's no one there ready to
> receive it because everyone happens to be busy doing something else that
> day you can't just leave it on the front doorstep.
So it is riskier to ship the damn thing to Florida than to Mars?
·········@jpl.nasa.gov (Erann Gat) writes:
>> What rots? (or, could you point to the right place to look? I
>> can't find the correct combination of terms for Google.)
>
> Lubrication mainly. (It doesn't rot, it outgasses. I think. This is at
> the hairy limits of my knowledge. If you really want to know details I
> can try to hunt down someone who actually knows and ask them.)
Fascinating. This makes me even more impressed by the engineering
miracles done when constructing the Voyagers, which still does
groundbreaking science (exploring the outer limits of the solar
systems, at a distance of half a light day) after 26 years in space!
(see http://voyager.jpl.nasa.gov/)
--
(espen)
·········@jpl.nasa.gov (Erann Gat) writes:
> > I've got the impression that between Earth and Mars, the periodicity
> > of the launch window is about yearly.
>
> For Mars it's once every two years.
Indeed, it's closer to two years: 22 months and two weeks:
(show (* 12 (/ mars-sidereal-orbit-period earth-sidereal-orbit-period )))
;; --> 22.56981404822919
--
__Pascal_Bourguignon__ http://www.informatimago.com/
There is no worse tyranny than to force a man to pay for what he doesn't
want merely because you think it would be good for him.--Robert Heinlein
http://www.theadvocates.org/
Pascal Bourguignon <····@thalassa.informatimago.com> writes:
> ·········@jpl.nasa.gov (Erann Gat) writes:
> > > I've got the impression that between Earth and Mars, the periodicity
> > > of the launch window is about yearly.
> >
> > For Mars it's once every two years.
>
> Indeed, it's closer to two years: 22 months and two weeks:
>
> (show (* 12 (/ mars-sidereal-orbit-period earth-sidereal-orbit-period )))
> ;; --> 22.56981404822919
I'm confused: why is that the right calculation? It looks
to me as if you've just calculated the length of the Martian
year, and I don't see why that should be the same thing as
the periodicity of the launch window. What am I missing?
--
Gareth McCaughan
.sig under construc
In article <··············@g.mccaughan.ntlworld.com>, Gareth McCaughan
<················@pobox.com> wrote:
> Pascal Bourguignon <····@thalassa.informatimago.com> writes:
>
> > ·········@jpl.nasa.gov (Erann Gat) writes:
> > > > I've got the impression that between Earth and Mars, the periodicity
> > > > of the launch window is about yearly.
> > >
> > > For Mars it's once every two years.
> >
> > Indeed, it's closer to two years: 22 months and two weeks:
> >
> > (show (* 12 (/ mars-sidereal-orbit-period earth-sidereal-orbit-period )))
> > ;; --> 22.56981404822919
>
> I'm confused: why is that the right calculation? It looks
> to me as if you've just calculated the length of the Martian
> year, and I don't see why that should be the same thing as
> the periodicity of the launch window. What am I missing?
It's not the right calculation, but it is (more or less) the right
result. It's just a concidence. The formula for computing the
periodicity of launch opportunities is:
(abs (+ 1.0 (/ 1.0 (- yp 1.0))))
where yp is the length of a year on the planet you're going to (in Earth
years). The number 2 just happens to be a fixed point for this function.
E.
·········@jpl.nasa.gov (Erann Gat) writes:
> In article <··············@g.mccaughan.ntlworld.com>, Gareth McCaughan
> <················@pobox.com> wrote:
>
> > Pascal Bourguignon <····@thalassa.informatimago.com> writes:
> >
> > > ·········@jpl.nasa.gov (Erann Gat) writes:
> > > > > I've got the impression that between Earth and Mars, the periodicity
> > > > > of the launch window is about yearly.
> > > >
> > > > For Mars it's once every two years.
> > >
> > > Indeed, it's closer to two years: 22 months and two weeks:
> > >
> > > (show (* 12 (/ mars-sidereal-orbit-period earth-sidereal-orbit-period )))
> > > ;; --> 22.56981404822919
> > I'm confused: why is that the right calculation? It looks
> > to me as if you've just calculated the length of the Martian
> > year, and I don't see why that should be the same thing as
> > the periodicity of the launch window. What am I missing?
Indeed. I'd rather write this kind of bug on usenet than in my
program. No wonder I did not write a programming line today...
> It's not the right calculation, but it is (more or less) the right
> result. It's just a concidence. The formula for computing the
> periodicity of launch opportunities is:
>
> (abs (+ 1.0 (/ 1.0 (- yp 1.0))))
>
> where yp is the length of a year on the planet you're going to (in Earth
> years). The number 2 just happens to be a fixed point for this function.
>
> E.
--
__Pascal_Bourguignon__ http://www.informatimago.com/
There is no worse tyranny than to force a man to pay for what he doesn't
want merely because you think it would be good for him.--Robert Heinlein
http://www.theadvocates.org/
·········@jpl.nasa.gov (Erann Gat) writes:
> In article <··············@g.mccaughan.ntlworld.com>, Gareth McCaughan
> <················@pobox.com> wrote:
>
> > Pascal Bourguignon <····@thalassa.informatimago.com> writes:
> >
> > > ·········@jpl.nasa.gov (Erann Gat) writes:
> > > > > I've got the impression that between Earth and Mars, the periodicity
> > > > > of the launch window is about yearly.
> > > >
> > > > For Mars it's once every two years.
> > >
> > > Indeed, it's closer to two years: 22 months and two weeks:
> > >
> > > (show (* 12 (/ mars-sidereal-orbit-period earth-sidereal-orbit-period )))
> > > ;; --> 22.56981404822919
> >
> > I'm confused: why is that the right calculation? It looks
> > to me as if you've just calculated the length of the Martian
> > year, and I don't see why that should be the same thing as
> > the periodicity of the launch window. What am I missing?
>
> It's not the right calculation, but it is (more or less) the right
> result. It's just a concidence. The formula for computing the
> periodicity of launch opportunities is:
>
> (abs (+ 1.0 (/ 1.0 (- yp 1.0))))
>
> where yp is the length of a year on the planet you're going to (in Earth
> years). The number 2 just happens to be a fixed point for this function.
Gotcha. And, actually, this is obvious (at least, it becomes
obvious when you write it in what I think is a clearer way).
Fix a ray from the sun, in the plane of the planets.
The angle from that ray to the ray (Sun->Earth) at
time t is, say, a*t; the angle from it to the ray
(Sun->Mars) at time t is, say, b*t. Then the angle
between the two rays is (a-b)*t. I don't know exactly
what determines the launch window, but obviously it
only depends on that last angle, so it repeats with
period 1/|a-b|.
(defun launch-window-period (period1 period2)
(/ (abs (- (/ period1) (/ period2)))))
The above is an oversimplification, assuming that
the orbits are coplanar and perfectly circular, and
that the positions of other planets don't matter.
It seems pretty clear that those are second-order
issues.
--
Gareth McCaughan
.sig under construc
Not commenting on the specifics of the calculation, but the reason that
it is close to two years is because both the earth and Mars are moving.
o It takes 1 year for the earth to be back in the same orbital position.
o But in that 1 year, Mars has performed roughly half of an orbit, so it
is now on the opposite side of the sun.
o So to catch up to the new Mars position, the earth needs another 1/2
year to get to the opposite side of the sun.
o But in that 1/2 year, Mars moves again, so you pretty much end up
having to compute the sum of the geometric series:
1 + 1/2 + 1/4 + 1/8 + ... = 2
--
Thomas A. Russ, USC/Information Sciences Institute
Pascal Bourguignon wrote:
> I've got the impression that between Earth and Mars, the periodicity
> of the launch window is about yearly.
Um, about once a martian year, or a little longer.
> But I assume that if they had delayed launch one year, they would have
> lost their budget!
s/lost/spent/ and you'll be closer to the facts. Stuff built for space
is hard to store on earth; gravity and atmosphere are hard on things that
are designed for minimum mass out of materials stable in vacuum. Delaying
launch would mean paying employee benefits and unemployment for thousands
of workers to be laid off for two years, then hiring them back. Meanwhile,
you'd need to get a whole nother batch of specialists to conserve the
hardware and test whether it was damaged in storage. And then you'd have
to pay for the contracts with everybody from food service personnel to
truckers when you jerked the schedules around, build a suitable storage
facility with all the $$$ and construction stuff that entails, rearrange
the funding so the Deep Space Network gets money to track your baby once
launched (they'll have gotten paid to build any new facilities in the year
launch was initially scheduled), etc, etc, etc.
A delayed space mission can be assumed to cost about a third of its value
per year delayed.
Bear
Pascal Bourguignon <····@thalassa.informatimago.com> writes:
> I've got the impression they did not test it a lot on Earth though...
In the January issue of IEEE Computer there is an article "NASA's
Mission Reliable" by Patrick Regan and Scott Hamilton on some of the
efforts which went into testing the robots' software. Apparently,
NASA tried hard to develop automatic testing tools for software
written in Java and C++, and apparently they did a good job in
catching a few concurrency-related bugs.
The article is targeted toward a general audience, not too technical,
more magazine/survey-style. Lisp is mentioned there once.
The abstract can be found here:
http://csdl.computer.org/comp/mags/co/2004/01/r1059abs.htm
Paul Tarvydas <········@allstream.net> wrote:
+---------------
| http://space.com/missionlaunches/spirit_relay_040124.html
| "There is a growing feeling here that the robot may have been taxed too
| much that is, too many "do this, do that" instructions were sent. That
| multi-tasking could have sparked the problem, according to sources here.
+---------------
More recent news:
<URL:http://spaceflightnow.com/mars/mera/040126spirit.html>
suggests that it was a matter of the flash (EEROM) filesystem metadata
(or maybe filesystem cache?) overflowing RAM, due to the length of time
that the system had been running and the amount of data captured:
It is now believed that the rover's flash memory had become
so full of files that the craft couldn't manage all of the
information stored aboard. Spirit bogged down because it didn't
have enough random access memory, or RAM, to handle the current
amount of files in the flash -- including data recorded during
its cruise from Earth to Mars and the 18 days of operations on
the red planet's surface.
...
And in that we realized that we had this reset problem. Based
on just kind of the hunch of our lead software architect, he
believed that the problem was probably associated with the mounting
of flash and initialization. There is a hardware command that
we can send that bypasses the software where we can actually
tell the hardware to not allow us to mount flash on initialization.
When we the next day actually sent the command to do that, software
initialized normally and was behaving like the software that we
had always known. It was a fantastic moment.
...
Right now, our most likely candidate for the issue has been
narrowed down a little bit. It is really an issue with the
file system in flash. Essentially, the amount of space required
in RAM to manage all of the files we have in flash is apparently
more than we initially anticipated.
...
Tomorrow, we are might try to access flash and do a little bit
of a health check on it. The next day we might try to delete
some files to see if our hunch is correct that it's really due
to the number of files that we are trying to manage on the flash
file system.
...
-Rob
-----
Rob Warnock <····@rpw3.org>
627 26th Avenue <URL:http://rpw3.org/>
San Mateo, CA 94403 (650)572-2607
Rob Warnock wrote:
> <URL:http://spaceflightnow.com/mars/mera/040126spirit.html>
http://www.nytimes.com/2004/01/27/science/space/27MARS.html
"Too many open files". Who wrote the flash file system - NASA or Wind
River?
pt