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Mars Rover Controlled By Java

Java, the software developed by Sun Microsystems in the mid-1990s as a
universal operating system for Internet applications, gave NASA a low-cost
and easy-to-use option for running Spirit, the robotic rover that rolled
onto the planet's surface on Thursday in search of signs of water and life.

http://news.com.com/2100-1007_3-5142...l?tag=nefd_top

l8r, Mike N. Christoff

Jul 17 '05
198 18194
On a sunny day (Sat, 17 Jan 2004 21:28:13 GMT) it happened Tony Hill
<hi************ *@yahoo.ca> wrote in
<67************ *************** ***@news.1usene t.com>:

You know, believe it or not, Java isn't all that slow. Here are a
couple of tests comparing different languages for very simple
algorithms: OK, but my latest test on THAT java mars rover soft ran 1.3 frames / second
on a 1 GHz PC.
Before it crashed mind you.

This was posted to sci.astro a week or 2 ago:from the rovers will be provided and can be loaded into the program.

http://mars.telascience.org/home/

"The Jet Propulsion Laboratory has released Maestro, a public version
of the primary software tool used by NASA scientists to operate the
Mars Exploration Rovers. Anyone can download Maestro for free from
http://mars.telascience.org/ and use it to follow along with the
rovers' progress during the mission. You can use Maestro to view
pictures from Mars in 2D and 3D and create simplified rover activity
plans. During the mission, updates will be released for Maestro
containing the latest images from Mars."


Me replying:
OK I downloaded the Linux version last night (I am in Europe),
realizing after it turned out to be a 2 1/2 hour download on a V90 modem,
that I really must be confident that lander worked this time....

Anyways it is based on java rle, the install script has some errors,
so you can not run it as the indicated executable,
but I had to run it as (I untarred it in /video/compile/maestro/ )
/video/compile/maestro/R2004_01-Public-Linux/JPL/SAP/bin/WITS
while 'SAP', that should start it (in /usr/local/bin), points to
SAP -> /video/compile/maestro/R2004_01-Public-Linux/WITS

So directory JPL/bin is missing from the softlink in /usr/local/bin
Also the install script 'forgets' to do
tar -xvf mer.tar
in
/video/compile/maestro/R2004_01-Public-Linux/JPL/SAP/WITS-db
so that you actually see some data.
Because of java (likely) the thing is slower then a dead snail glued with
superglue to a scrapped Apollo.
I followed the intro to the point where it had to move to a target, then it
froze with this message in the console:

An unexpected exception has been detected in native code outside the VM.
Unexpected Signal : 11 occurred at PC=0x400C32F7
Function=memcpy +0x27
Library=/lib/libc.so.6

Current Java thread:
*************** *
Another exception has been detected while we were handling last error.
Dumping information about last error:
ERROR REPORT FILE = (N/A)
PC = 0x0x400c32f7
SIGNAL = 11
FUNCTION NAME = memcpy
OFFSET = 0x27
LIBRARY NAME = /lib/libc.so.6
Please check ERROR REPORT FILE for further information, if there is any.
Good bye.

So, 1.3 frames / second before it crashed, and this system plays live video
at normal speed no problem.
But THAT code is written in asm and C.
I remember the old vrml browsers (was there al the way from the beginning).
After some of these got ported to Java it was a factor 10 slower (at least).
And NO reason in the world to do that, portability of good C code is excellent.
Java is a mistake.

Jul 17 '05 #21
In article <40************ ***@hate.spam.n et>,
Uncle Al <Un******@hate. spam.net> wrote:
Local atmospheric pressure is 7-10 torr. Earth sea level is 760
torr. How many planes do you know that cruise at 100,000 feet absent
any oxygen at all?
The AeroVironment Helios Prototype, for one:

http://www.aerovironment.com/area-ai.../unmanned.html
Martian aircraft are a bad dream.


No more than Mars sample return or numerous other challenging but
entirely feasible tasks.

Jon
__@/
Jul 17 '05 #22
On Sat, 17 Jan 2004 16:52:45 GMT, Jan Panteltje
<pN************ *@yahoo.com> wrote:
On a sunny day (Sat, 17 Jan 2004 10:53:34 +0100) it happened "Dalibor Hrg"
<da*********@f er.hr> wrote in <bu**********@l s219.htnet.hr>:
We can say that Java is most useful language on Mars today :))) You know,
the time of .NET is coming while Java has already took its place in
history. Nothing can change that, Java is simply great thing!

Java is the worst thing that could happen to computing since the
invention of the chuwing gum hard disk.
It is slow, slow, slow, slow, SLOW, and not to mention slow.
And on top of that it is slow.


Haven't tried it lately, have you ;-)

--
Al Balmer
Balmer Consulting
re************* ***********@att .net
Jul 17 '05 #23
|
| >On a sunny day (Sat, 17 Jan 2004 10:53:34 +0100) it happened "Dalibor
Hrg"
| ><da*********@f er.hr> wrote in <bu**********@l s219.htnet.hr>:
| >
| >>You know,
| >>the time of .NET is coming

Bwa Ha HA Ha Ha Ha Ha HA.
Thanks for making me laugh at the end of a bad day :-)
--
-P
Jul 17 '05 #24
> Java is the worst thing that could happen to computing since the
invention of the chuwing gum hard disk.
It is slow, slow, slow, slow, SLOW, and not to mention slow.
And on top of that it is slow.


And that's why it's such an important step forward: it makes it possible for
people to realize that speed is not all that important when choosing
a programming language.

Now that we've taken this step, we can start to think about the next step:
focus on safety and correctness.
Stefan
Jul 17 '05 #25
Stefan Monnier <mo*****@iro.um ontreal.ca> writes:
Java is the worst thing that could happen to computing since the
invention of the chuwing gum hard disk.
It is slow, slow, slow, slow, SLOW, and not to mention slow.
And on top of that it is slow.


And that's why it's such an important step forward: it makes it possible for
people to realize that speed is not all that important when choosing
a programming language.

Now that we've taken this step, we can start to think about the next step:
focus on safety and correctness.


Actually, speed is very often an important aspect. The question is,
speed of what? If you spent five days writing/debugging a program in
C++ that could be written in two hours in LISP (for example), and the
program is only going to be used for a single experiment or set of
experiments, than most likely the improvement in performance that you
got by writing it in C++ is offset by the time spent writing/debugging
it. Obviously, as been said several times, it depends on what the
language is being used for. If the software is for security-critical
uses, C++ is probably a bad choice. If the software is for cracking a
particular encryption algorithm, C might be a very good choice. (Of
course, assembly might be even better!)

---------------------------------------------------------------------
| "Good and evil both increase at compound
Ben Hocking, Grad Student | interest. That is why the little
ho*****@cs.virg inia.edu | decisions you and I make every day are of
| such infinite importance." - C. S. Lewis
---------------------------------------------------------------------
Jul 17 '05 #26
On a sunny day (Tue, 20 Jan 2004 11:49:32 -0700) it happened Alan Balmer
<al******@att.n et> wrote in <b0************ *************** *****@4ax.com>:
On Sat, 17 Jan 2004 16:52:45 GMT, Jan Panteltje
<pN*********** **@yahoo.com> wrote:
On a sunny day (Sat, 17 Jan 2004 10:53:34 +0100) it happened "Dalibor Hrg"
<da*********@ fer.hr> wrote in <bu**********@l s219.htnet.hr>:
We can say that Java is most useful language on Mars today :))) You know,
the time of .NET is coming while Java has already took its place in
history. Nothing can change that, Java is simply great thing!Java is the worst thing that could happen to computing since the
invention of the chuwing gum hard disk.
It is slow, slow, slow, slow, SLOW, and not to mention slow.
And on top of that it is slow.


Haven't tried it lately, have you ;-)

Oh yes I did, but nervous Jave people start spamming my email
that I really *should not mention Java is slow*, well, read my other post
in this tread.
And THAT was written by NASA.
Penty of stuff around to show it, get real.

--
Al Balmer
Balmer Consulting

mmm
Solutions of Yesterday already NOW on your desktop with JAVA (snailmark).
Sorry
Jul 17 '05 #27
On a sunny day (Tue, 20 Jan 2004 19:07:16 GMT) it happened Stefan Monnier
<mo*****@iro.um ontreal.ca> wrote in
<jw************ *************** ****@asado.iro. umontreal.ca>:
Java is the worst thing that could happen to computing since the
invention of the chuwing gum hard disk.
It is slow, slow, slow, slow, SLOW, and not to mention slow.
And on top of that it is slow.


And that's why it's such an important step forward: it makes it possible for
people to realize that speed is not all that important when choosing
a programming language.

Now that we've taken this step, we can start to think about the next step:
focus on safety and correctness.
Stefan

How safe is a car that cannot accelerate (when needed).
How correct is a solution that runs 10x slower then other ones.
(like web browser).
What does it give us, so you cannot program with pointers, so
you do not want to learn that, so you use java.
Popups, webcrap...
Or use 10 x power for the same final speed, efficient?
Java is as safe as the one who programs with it.
If you forget (because you think it is so safe) about any security issues,
then your eventual lack of knowledge about these issues will break
your code security.
I cannot really think of one useful application of Java except
burning it.
It is like BASIC, except slower, and less used.
Hey I am not just pestering, it is TRUE.
NOTHING is slower then java.

Jul 17 '05 #28
> How safe is a car that cannot accelerate (when needed).
How correct is a solution that runs 10x slower then other ones.
(like web browser).
What does it give us, so you cannot program with pointers, so
you do not want to learn that, so you use java.
Popups, webcrap...
Or use 10 x power for the same final speed, efficient?


Why don't you go and learn about programming languages (and their history)?
Stefan
Jul 17 '05 #29
<snip>
Why mention oxygen specifically?
The solar panels mentioned would have no
problem with the complete absence of oxygen.

My dear friend, planes need atmosphere not only for combustion but
also for generating the required lift by its wings or copter blades or
whatever. A rarefied atmosphere would not be able to generate enough
lift at a decent velocity like on earth. of course by increasing the
velocity several times we can generate some lift, but that would be a
totally wasteful use of energy.

Besides to keep a copter in the air it woulf consume a great deal of
energy which could be otherwise utilised for some other purpose.
..Though a battery powered chopper would
still be little more effective than one that
uses internal combustion.

again battery power does not solve the probelm of generating enough
lift in a rarefied atmosphere.

regards,
Seemanta Dutta
Jul 17 '05 #30

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