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Mars Rover Controlled By Java

P: n/a
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 #1
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P: n/a
Michael N. Christoff wrote:
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

The software on earth is in java, but is the software running on the
thing itself java?
Jul 17 '05 #2

P: n/a
Thats' correct. Look at
http://www.cnn.com/2004/TECH/space/0...eut/index.html

Had it been running Microsoft .NET, the payload would be heavier due to more
memory needed to run Windows, the cost higher due to licensing fees NASA
would have to pay Bill Gates/Microsoft, and by now would be sending back the
"blue screen of death" instead of the martian surface!
"Ken Larson" <ke**********@mindspring.com> wrote in message
news:bu*************@news.t-online.com...
Michael N. Christoff wrote:
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

The software on earth is in java, but is the software running on the
thing itself java?

Jul 17 '05 #3

P: n/a
Read the article carefully. Java is being used to create 3D views of
terrain, and for command and control functions, ON EARTH. The last
paragraph correctly states that Wind River Systems made the embedded
software in the Spirit and Opportunity rovers. They run applications
created by JPL which execute on the VxWorks real-time operating system
(RTOS). I know this because a little of my work is in that RTOS - I
worked for Wind River until recently.

If you want more info on VxWorks, see the web site: www.windriver.com

The VxWorks RTOS also ran the Mars Lander and is in many other active
NASA probes like Stardust.

--mitch

JavaJunkie wrote:
Thats' correct. Look at
http://www.cnn.com/2004/TECH/space/0...eut/index.html

Had it been running Microsoft .NET, the payload would be heavier due to more
memory needed to run Windows, the cost higher due to licensing fees NASA
would have to pay Bill Gates/Microsoft, and by now would be sending back the
"blue screen of death" instead of the martian surface!
"Ken Larson" <ke**********@mindspring.com> wrote in message
news:bu*************@news.t-online.com...
Michael N. Christoff wrote:
Java, the software developed by Sun Microsystems in the mid-1990s as a
universal operating system for Internet applications, gave NASA a low-costand 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


The software on earth is in java, but is the software running on the
thing itself java?


Jul 17 '05 #4

P: n/a
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!

I was thinking, NASA could run some servers which will present Spirit's 3D
visualization. They could use Java3D in some applet so anybody interested
could navigate path that Spirit has traveled. It will be nice to see that.
How many cameras Spirit has anyway?

I was also thinking why all robots or searchers have wheels, I mean if they
are doing some research on land ok than, but it will be easier to use some
flying robot like small helicopter or something for making map. It will have
its platform with solar panels, it can go faster and I think travel lot more
distance. The platform can have wheels so it can move. The helicopter can be
useful to analyze around the platform and navigate platform. Let's say Sprit
and small robo-copter will be ideal combination. It's just suggestion.

At the end flying robots will depend on Mars's atmosphere, right?

"mitch" <realtime@-no-spam-acm.org> wrote in message
news:10*************@corp.supernews.com...
Read the article carefully. Java is being used to create 3D views of
terrain, and for command and control functions, ON EARTH. The last
paragraph correctly states that Wind River Systems made the embedded
software in the Spirit and Opportunity rovers. They run applications
created by JPL which execute on the VxWorks real-time operating system
(RTOS). I know this because a little of my work is in that RTOS - I
worked for Wind River until recently.

If you want more info on VxWorks, see the web site: www.windriver.com

The VxWorks RTOS also ran the Mars Lander and is in many other active
NASA probes like Stardust.

--mitch

JavaJunkie wrote:
Thats' correct. Look at
http://www.cnn.com/2004/TECH/space/0...eut/index.html

Had it been running Microsoft .NET, the payload would be heavier due to more memory needed to run Windows, the cost higher due to licensing fees NASA
would have to pay Bill Gates/Microsoft, and by now would be sending back the "blue screen of death" instead of the martian surface!
"Ken Larson" <ke**********@mindspring.com> wrote in message
news:bu*************@news.t-online.com...
Michael N. Christoff wrote:

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 rolledonto 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
The software on earth is in java, but is the software running on the
thing itself java?

Jul 17 '05 #5

P: n/a
da*********@fer.hr (Dalibor Hrg) wrote (abridged):
We can say that Java is most useful language on Mars today :)))


Err, I read him as saying Java is /not/ on Mars today.

-- Dave Harris, Nottingham, UK
Jul 17 '05 #6

P: n/a
> Had it been running Microsoft .NET, the payload would be heavier due to more
memory needed to run Windows, the cost higher due to licensing fees NASA
would have to pay Bill Gates/Microsoft, and by now would be sending back the
"blue screen of death" instead of the martian surface!


You give it too much credit!
Jul 17 '05 #7

P: n/a
Dalibor Hrg wrote:
[snip]
I was also thinking why all robots or searchers have wheels, I mean if they
are doing some research on land ok than, but it will be easier to use some
flying robot like small helicopter or something for making map. It will have
its platform with solar panels, it can go faster and I think travel lot more
distance. The platform can have wheels so it can move. The helicopter can be
useful to analyze around the platform and navigate platform. Let's say Sprit
and small robo-copter will be ideal combination. It's just suggestion.

[snip]

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? Martian aircraft are a bad dream.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!
Jul 17 '05 #8

P: n/a
"Uncle Al" <Un******@hate.spam.net> wrote in message
news:40***************@hate.spam.net...
| Dalibor Hrg wrote:
| [snip]
....
| > flying robot like small helicopter or something for making
map. It will have
| > its platform with solar panels, it can go faster and I think
travel lot more
| > distance.
....
| 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?

Why mention oxygen specifically?
The solar panels mentioned would have no
problem with the complete absence of oxygen.

...Though a battery powered chopper would
still be little more effective than one that
uses internal combustion.

And getting back to the original
thrust of this thread.

No, even if it were possible to make
a craft that could fly in Mars' atmosphere,
that would not be controlled by Java either
as it would violate Sun's license.

[ Why the heck was this cross-posted to
sci.physics? Some of the other groups are
borderline, but that one's off the wall.. ]

--
Andrew Thompson
* http://www.PhySci.org/ PhySci software suite
* http://www.1point1C.org/ 1.1C - Superluminal!
* http://www.AThompson.info/andrew/ personal site
Jul 17 '05 #9

P: n/a
On a sunny day (Sat, 17 Jan 2004 10:53:34 +0100) it happened "Dalibor Hrg"
<da*********@fer.hr> wrote in <bu**********@ls219.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.
Jul 17 '05 #10

P: n/a
On a sunny day (Sat, 17 Jan 2004 12:32 +0000 (GMT Standard Time)) it happened
br******@cix.co.uk (Dave Harris) wrote in
<me***********************@brangdon.m>:
da*********@fer.hr (Dalibor Hrg) wrote (abridged):
We can say that Java is most useful language on Mars today :)))


Err, I read him as saying Java is /not/ on Mars today.

Correct, and the fact that we already have pics proves that.

Jul 17 '05 #11

P: n/a
> No, even if it were possible to make
a craft that could fly in Mars' atmosphere,
that would not be controlled by Java either
as it would violate Sun's license.


Is the java License valid in other planets? :-)
Jul 17 '05 #12

P: n/a
In article <40***************@hate.spam.net>, Uncle Al
<Un******@hate.spam.net> writes
Dalibor Hrg wrote:
[snip]
I was also thinking why all robots or searchers have wheels, I mean if they
are doing some research on land ok than, but it will be easier to use some
flying robot like small helicopter or something for making map. It will have
its platform with solar panels, it can go faster and I think travel lot more
distance. The platform can have wheels so it can move. The helicopter can be
useful to analyze around the platform and navigate platform. Let's say Sprit
and small robo-copter will be ideal combination. It's just suggestion.

[snip]

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? Martian aircraft are a bad dream.

That's as maybe, but ESA (European Space Agency) are dreaming of putting
Aerostats on Mars. I heard a talk from someone involved in this. See
also http://users.aber.ac.uk/dpb/aerobots.html. From what I remember,
they are balloons with fan motors. Much R&D will go into interpreting
the pictures they take well enough to only send back the interesting
bits. They illustrated the talk with a radio-controlled helium balloon
they have been using to learn the practicalities. Don't know the
programming language, but those involved have experience in Ada and
Matlab.

(cross-posting trimmed to only moderately insane).
--
A. G. McDowell
Jul 17 '05 #13

P: n/a
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**********@ls219.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.


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:

http://www.bagley.org/~doug/shootout/index2.shtml

http://osnews.com/story.php?news_id=5602

While these simple tests might not hit on some of the weaknesses of a
JIT language like Java, they do tend to indicate that the performance
for most tests isn't all that bad.
That being said, the fact remains that Java is NOT being used on Mars
today. The Java stuff the original article talked about was all
earth-based stuff. In fact, it wasn't even the thing that was getting
the data from the Mars rover, simply the component that let people
view the data after it had been received.

The code on the rover wasn't specified, but it's most likely C/C++ as
that is the primary development language for Wind River VxWorks. I'm
not even sure if that OS has Java support, though even if it did it
would be a BAD choice. Java is NOT designed with real-time operating
systems in mind. It's a fine language for what it is, but it's not
really a suitable choice for this application. Ada might actually be
the best choice, as this is the sort of thing that language was
designed for, but C/C++ is a good alternative that is widely supported
and well known.

-------------
Tony Hill
hilla <underscore> 20 <at> yahoo <dot> ca
Jul 17 '05 #14

P: n/a
Andrew Thompson wrote:

No, even if it were possible to make
a craft that could fly in Mars' atmosphere,
that would not be controlled by Java either
as it would violate Sun's license.


Irrelevant. If you really do see Java in space, it won't be made by Sun.

http://www.aicas.com/press/pr_12_en_24-Oct-03.html

[sci.physics deleted from X-postings]

--
Chris Gray ch***@kiffer.eunet.be

Jul 17 '05 #15

P: n/a
Uncle Al 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? Martian aircraft are a bad dream.


Hmm. Then the test of a Mars glider plane back in August of 2001 was
just a bad dream? ;-) Work has begun on a propellered version of the
glider cited below. Enjoy.

--mitch
----------------------------

http://amesnews.arc.nasa.gov/releases/2001/01_58AR.html

Michael Mewhinney Aug. 13, 2001
NASA Ames Research Center, Moffett Field, CA
Phone: 650-604-5026 or 604-9000
jb****@mail.arc.nasa.gov or mm********@mail.arc.nasa.gov
RELEASE: 01-58AR

AMES COMPLETES SUCCESSFUL TEST OF MARS AIRPLANE PROTOTYPE

Soaring gracefully down to Earth from a balloon floating 101,000 feet high
above Oregon, a NASA prototype of an airplane that someday may fly over
Mars successfully completed a high-altitude flight test this week.

Conducted at Oregon's Tillamook airport by the Kitty Hawk 3 project at NASA
Ames Research Center, Moffett Field, CA, the test was designed to validate
the aerodynamic performance of the prototype. Nicknamed "Orville" after
one of the famed Wright brothers who first flew on Dec. 17, 1903, the NASA
731 glider was dropped from a helium-filled balloon that towed it up to an
altitude of 101,000 feet - the highest ever for such a test - before
releasing it. Engineers and scientists hailed the test as a great success.

"It was a great flight and everything went really well. It appears that we
realized all of our test objectives," exclaimed a jubilant Andy Gonzales,
an Ames aerospace engineer who served as the flight test director.
Low-altitude tests of NASA 729, another prototype called "Wilbur," were
conducted last month at Ames.

"Mars has always fascinated people," said Larry Lemke, an aerospace
engineer at NASA Ames who serves as Ames' project manager for advanced Mars
mobility concepts, which include airplanes as well as other systems.
"Every time we send a mission up there, we come back with fascinating
discoveries."

According to Lemke, a Mars airplane is an idea whose time has come. "The
Mars airplane is an idea that has been around for about 25 years, and over
the past five years or so, it has been growing in popularity," he said. "I
think a Mars airplane will play a role in exploring the Red Planet."

Conventional in appearance, the Mars airplane concept developed by Ames
engineers features a long, straight wing and twin tails in the rear. The
remote-controlled glider tested in Oregon featured an approximately
four-foot-long fuselage and an eight-foot wing span.

"The flying we have successfully completed in Oregon is very similar to the
flying that we will be doing over Mars during a productive exploration
mission," Lemke said. "One unique aspect of flying a Mars mission with an
airplane is that it must be constructed in a fold-up configuration in order
to fit inside a spacecraft."

In its future configuration for Mars, the aircraft is expected to have its
own propeller propulsion system capable of operating in the Mars
atmosphere, which is comprised mostly of carbon dioxide. It will also
carry a variety of sophisticated instruments to observe and conduct science
experiments.

"The possibility of life on Mars is a very hot topic and an interesting
question, so I'm sure you will find instruments on board that are designed
to find signs of water on Mars, which is necessary for life," Lemke said.

"In addition, we would have a large array of cameras on the airplane to be
able to see large areas of the Mars terrain in very high resolution," Lemke
said. He said the cameras aboard the aircraft would be so precise, they
could see objects on Mars as small as the size of a quarter. "I think the
images will be stunning," he said. "During a Mars airplane mission, we will
be able to view the planet at very close proximity and this will convey to
the public that there is a real planet there, not just an abstract."

"Our test flight at Tillamook airport showed the airplane's flight was very
smooth and stable which makes for a good platform for science instruments,"
said Gonzales.

Ames engineers predict the next few years will be challenging, as they
prepare for a potential mission to Mars. "We will be expanding the envelope
and developing a much more complex aircraft for exploring Mars," Lemke
said. The next step will be to develop a Mars airplane model with folding
wings and later, one with a propeller propulsion system.

-- end --

Note to Broadcasters: A video file related to this news release is
scheduled for distribution via satellite on NASA Television on August 14,
2001. Because feed times and the schedule are subject to change, please
check the NASA TV video file line-up on the web at
ftp://ftp.hq.nasa.gov/pub/pao/tv-advisory/nasa-tv.txt

NASA TV is available on GE-2, transponder 9C at 85 degrees west longitude,
with vertical polarization; frequency is on 3880.0 megahertz, with audio on
6.8 megahertz. For general questions about the video file, call NASA
Headquarters, Washington, DC: Fred Brown at 202/358-0713

Jul 17 '05 #16

P: n/a
mitch wrote:

Uncle Al 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? Martian aircraft are a bad dream.
Hmm. Then the test of a Mars glider plane back in August of 2001 was
just a bad dream? ;-) Work has begun on a propellered version of the
glider cited below. Enjoy.

AMES COMPLETES SUCCESSFUL TEST OF MARS AIRPLANE PROTOTYPE
The empirical fact is that lowland Martian air pressure is 7-10 torr.
The is equivalent to 120,000-100,000 feet terrestrial altitude. If
the silly thing will be diddling at even 1000 ft altitude Martian, the
air will be thinner. I don't care if Hillary Ramrod Clinton left a
big warm wetspot on the chute prior to deployment. Stuff doesn't fly
that high - certainly absent oxygen in the intake.

"Ye canna break the laws of physics."

The Concorde flew at 60,000 feet and gulped air like a madman. The
U-2 did 75,000 feet, breathed air, and it was a bitch to fly. The
SR-71 Blackbird could barely do 100,000 feet while at Mach 3+ with its
cockpit windshield simmering at 620 F. It drank 8000 gallons/hr of
fuel. It breathed 6 million ft^3 of air/minute.
Soaring gracefully down to Earth from a balloon floating 101,000 feet high
above Oregon, a NASA prototype of an airplane that someday may fly over
Mars successfully completed a high-altitude flight test this week.


Yeah, right. They have an airfoil that works in vacuum. What is its
payload - one NASA decal? Learn the difference between Official Truth
and real world truth.

[snip]

--
Uncle Al
http://www.mazepath.com/uncleal/qz.pdf
http://www.mazepath.com/uncleal/eotvos.htm
(Do something naughty to physics)
Jul 17 '05 #17

P: n/a
"Uncle Al" <Un******@hate.spam.net> wrote in message
news:40***************@hate.spam.net...

[SNIP]
The empirical fact is that lowland Martian air pressure is 7-10 torr.
The is equivalent to 120,000-100,000 feet terrestrial altitude. If
the silly thing will be diddling at even 1000 ft altitude Martian, the


According to that link they've tested it at over 100,000 ft
already. Cute idea, but I figure the air-ship type option
may be more robust and easier to deploy - plus if something
momentarily breaks it's less like to fall out of the sky.

Cheers,
Rupert
Jul 17 '05 #18

P: n/a
"Rupert Pigott" <ro*@dark-try-removing-this-boong.demon.co.uk>
wrote in message news:10***************@saucer.planet.gong...
| "Uncle Al" <Un******@hate.spam.net> wrote in message
| news:40***************@hate.spam.net...
|
| [SNIP]
|
| > The empirical fact is that lowland Martian air pressure is
7-10 torr.
| > The is equivalent to 120,000-100,000 feet terrestrial
altitude. If
| > the silly thing will be diddling at even 1000 ft altitude
Martian, the
|
| According to that link they've tested it at over 100,000 ft
| already. Cute idea, but I figure the air-ship type option
| may be more robust and easier to deploy - plus if something
| momentarily breaks it's less like to fall out of the sky.

This topic was discussed recently on sci.space.tech.
One of the problems identified for heavier than..
atmosphere craft was the *runway length required
to take-off or land.

[ And to those that would jump in and suggest
keeping it aloft continuously, that is impractical
with sandstorms, ..even assuming you could squeeze
a 'little' RTG into it, and still get it off the ground. ]

Balloon, or better still, orbiter with a bloody
good telescope. No dust, no sand, no runways
to deal with and you can cover far more area.

* Well, of _course_ they would be using all
those really _long_ runways built on Mars
during WWII. ;-)

--
Andrew Thompson
* http://www.PhySci.org/ PhySci software suite
* http://www.1point1C.org/ 1.1C - Superluminal!
* http://www.AThompson.info/andrew/ personal site
Jul 17 '05 #19

P: n/a

"Tony Hill" <hi*************@yahoo.ca> wrote in message
news:67******************************@news.1usenet .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**********@ls219.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.


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:

http://www.bagley.org/~doug/shootout/index2.shtml

http://osnews.com/story.php?news_id=5602

While these simple tests might not hit on some of the weaknesses of a
JIT language like Java, they do tend to indicate that the performance
for most tests isn't all that bad.
That being said, the fact remains that Java is NOT being used on Mars
today. The Java stuff the original article talked about was all
earth-based stuff. In fact, it wasn't even the thing that was getting
the data from the Mars rover, simply the component that let people
view the data after it had been received.

The code on the rover wasn't specified, but it's most likely C/C++ as
that is the primary development language for Wind River VxWorks. I'm
not even sure if that OS has Java support, though even if it did it
would be a BAD choice. Java is NOT designed with real-time operating
systems in mind.


That is correct. However, standard Java is also not a good choice for cell
phones. You need Java Micro edition (J2ME) for this. On that note, there
is much work being done on developing a version of Java for real time
systems.

l8r, Mike N. Christoff

Jul 17 '05 #20

P: n/a
On a sunny day (Sat, 17 Jan 2004 21:28:13 GMT) it happened Tony Hill
<hi*************@yahoo.ca> wrote in
<67******************************@news.1usenet.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

P: n/a
In article <40***************@hate.spam.net>,
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

P: n/a
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**********@ls219.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

P: n/a
|
| >On a sunny day (Sat, 17 Jan 2004 10:53:34 +0100) it happened "Dalibor
Hrg"
| ><da*********@fer.hr> wrote in <bu**********@ls219.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

P: n/a
> 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

P: n/a
Stefan Monnier <mo*****@iro.umontreal.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.virginia.edu | decisions you and I make every day are of
| such infinite importance." - C. S. Lewis
---------------------------------------------------------------------
Jul 17 '05 #26

P: n/a
On a sunny day (Tue, 20 Jan 2004 11:49:32 -0700) it happened Alan Balmer
<al******@att.net> 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**********@ls219.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

P: n/a
On a sunny day (Tue, 20 Jan 2004 19:07:16 GMT) it happened Stefan Monnier
<mo*****@iro.umontreal.ca> wrote in
<jw*******************************@asado.iro.umont real.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

P: n/a
> 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

P: n/a
<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

P: n/a
seemanta dutta wrote:
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.


So he is right: oxygen does not, specifically, matter.
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.


Don't forget that the necessary lift is *also* much lower on Mars
since it has only one tenth the mass!

Jul 17 '05 #31

P: n/a
In article <bu************@ID-161931.news.uni-berlin.de>, Michael Borgwardt <br****@brazils-animeland.de> writes:
seemanta dutta wrote:
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.


So he is right: oxygen does not, specifically, matter.
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.


Don't forget that the necessary lift is *also* much lower on Mars
since it has only one tenth the mass!

Well, the gravity is not proporitonal to mass alone. It's radius is
smaller as well, so its gravity, on surface, is doen only by a factor
of 2 or so. Its atmospheric density, on the other hand, is down by
more than two orders of magnitude. So, the necessary lift is lower by
much less than the available lift.

Mati Meron | "When you argue with a fool,
me***@cars.uchicago.edu | chances are he is doing just the same"
Jul 17 '05 #32

P: n/a
Would it be *on-topic* to query the relevance of this to...

comp.arch
comp.distributed
comp.lang.java
comp.lang.java.programmer
comp.object
comp.programming
comp.theory
sci.physics

I'm all for serendipity and all that, and I've learned all sorts
of things from off-topic threads, but I think the OP's claim (and
hence the official subject of the thread) was shot down with the
first or second reply and we've given aircraft and Java advocacy
a good run now.
Jul 17 '05 #33

P: n/a
In comp.arch Jan Panteltje <pN*************@yahoo.com> wrote:
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.


I think most people have that impression either by playing with Java 1.0
(or listening to those who have), or by using Swing applications.

Newer Java versions and graphical applications using ie. SWT perform
the same as native C/Fortran applications. In fact, the new Hotspot
optimizer in 1.4 is quite good at numerical codes too. For some large
scale computations, my Java codes perform identical to Fortran codes,
with the added benefits of readability and maintainability, not to
mention trivial cross-platform deployment (from my desktop to the local
supercomputer, with excellent scalability).

I might add that Java w/Hotspot quite often outperforms vanilla C
codes, it's only when adding lots of optimization flags to the compiler
that the performance gap closes.

--
Bjørn-Ove Heimsund
Centre for Integrated Petroleum Research
University of Bergen, Norway

Jul 17 '05 #34

P: n/a
> Newer Java versions and graphical applications using ie. SWT perform
the same as native C/Fortran applications. In fact, the new Hotspot
optimizer in 1.4 is quite good at numerical codes too.
While that is likely true, ...
For some large
scale computations, my Java codes perform identical to Fortran codes,
Really? Even if you compile with optimization?
with the added benefits of readability and maintainability, not to
mention trivial cross-platform deployment (from my desktop to the local
supercomputer, with excellent scalability).
I consider a reasonably well-written F95 program to be very maintainable
and more portable than Java - if only for the fact that there's only one
F95 standard all compilers are written to, while there are several
incompatible (in various ways) Java "standards" around, not to mention
the different thread semantics of different implementations.
I might add that Java w/Hotspot quite often outperforms vanilla C
codes, it's only when adding lots of optimization flags to the compiler
that the performance gap closes.


For any modern compiler of a 3GL language, not compiling with (the equivalent
of) -fast is grossly negligent.

Jan
Jul 17 '05 #35

P: n/a
In comp.arch Jan C. Vorbrüggen <jv**********@mediasec.de> wrote:
For some large
scale computations, my Java codes perform identical to Fortran codes,
Really? Even if you compile with optimization?


Yes, but I might add that the things I do are not easily vectorizable
(sparse matrix calculations). For dense array computations, a good
compiler can do fancy unrolling tricks and other things which is not
(yet) available in Java nor in Hotspot.
with the added benefits of readability and maintainability, not to
mention trivial cross-platform deployment (from my desktop to the local
supercomputer, with excellent scalability).


I consider a reasonably well-written F95 program to be very maintainable
and more portable than Java - if only for the fact that there's only one
F95 standard all compilers are written to, while there are several


It's very easy to create unmaintainable code in any language, Java is no
exception. It's just that Java doesn't have a 40 year legacy baggage,
and encourages good design practices. Java seems to be well recieved
in some computer science institutes as well, especially as an
introduction to OO programming.

On the portability side, I have had issues porting some F95 codes
between compilers, both of which had different ideas how the standard
were to be interpreted (and the compilers were quite new too). F77
compiles nicely, though.
incompatible (in various ways) Java "standards" around, not to mention
the different thread semantics of different implementations.


Since Java 1.2, I have yet to encounter any issues with thread
implementations, be it on AIX, Solaris, Linux or Windows. There are
of course some more issues relating to thread local storage and
caching, but the semantics of this is being worked out (for Java 1.5)
I might add that Java w/Hotspot quite often outperforms vanilla C
codes, it's only when adding lots of optimization flags to the compiler
that the performance gap closes.


For any modern compiler of a 3GL language, not compiling with (the equivalent
of) -fast is grossly negligent.


Agreed. But many folks around here run their codes compiled with
"f77 -g" (not that I do that, of course :-)

--
Bjørn-Ove Heimsund
Centre for Integrated Petroleum Research
University of Bergen, Norway
Jul 17 '05 #36

P: n/a
On Wed, 21 Jan 2004 10:11:07 -0000, "Ken Hagan"
<K.*****@thermoteknix.co.uk> wrote:
Would it be *on-topic* to query the relevance of this to...

comp.arch
comp.distributed
comp.lang.java
comp.lang.java.programmer
comp.object
comp.programming
comp.theory
sci.physics

I'm all for serendipity and all that, and I've learned all sorts
of things from off-topic threads, but I think the OP's claim (and
hence the official subject of the thread) was shot down with the
first or second reply and we've given aircraft and Java advocacy
a good run now.

In unmoderated groups, threads don't have "official" subjects, and
thread drift will be with us forever. Messages do have topicality,
however, and the comparison and qualification of programming
languages, and specifically Java, would seem to be topical in at least
two of the above groups. I will volunteer to trim the cross-post list,
however.

As for your question, yes. Topicality is always on-topic.

--
Al Balmer
Balmer Consulting
re************************@att.net
Jul 17 '05 #37

P: n/a
seemanta dutta wrote:
of course by increasing the velocity several times we can generate
some lift, but that would be a totally wasteful use of energy.


One can also increase wing area. This is, e.g., why 747s can land
so amazingly slowly for such a big bird.

--
|_ CJSonnack <Ch***@Sonnack.com> _____________| How's my programming? |
|_ http://www.Sonnack.com/ ___________________| Call: 1-800-DEV-NULL |
|_____________________________________________|___ ____________________|
Jul 17 '05 #38

P: n/a
seemanta dutta wrote:
of course by increasing the velocity several times we can generate
some lift, but that would be a totally wasteful use of energy.


One can also increase wing area. This is, e.g., why 747s can land
so amazingly slowly for such a big bird.

--
|_ CJSonnack <Ch***@Sonnack.com> _____________| How's my programming? |
|_ http://www.Sonnack.com/ ___________________| Call: 1-800-DEV-NULL |
|_____________________________________________|___ ____________________|
Jul 17 '05 #39

P: n/a
>
The code on the rover wasn't specified, but it's most likely C/C++ as
that is the primary development language for Wind River VxWorks. I'm
not even sure if that OS has Java support, though even if it did it
would be a BAD choice. Java is NOT designed with real-time operating
systems in mind. It's a fine language for what it is, but it's not
really a suitable choice for this application. Ada might actually be
the best choice, as this is the sort of thing that language was
designed for, but C/C++ is a good alternative that is widely supported
and well known.


Seems like Java may well be used on the actual rover in the future:

Jim Sculley wrote:
<quote>
In any event this entire discussion has ignored the Realtime
Specification for Java, implementations of which are being used in
mission critical apps, such as control systems for a future Mars rover:

http://www.opengroup.org/rtforum/upl...den_Gate_May01
-v05.pdf

Jim S.
</quote>

l8r, Mike N. Christoff

Jul 17 '05 #40

P: n/a
>
The code on the rover wasn't specified, but it's most likely C/C++ as
that is the primary development language for Wind River VxWorks. I'm
not even sure if that OS has Java support, though even if it did it
would be a BAD choice. Java is NOT designed with real-time operating
systems in mind. It's a fine language for what it is, but it's not
really a suitable choice for this application. Ada might actually be
the best choice, as this is the sort of thing that language was
designed for, but C/C++ is a good alternative that is widely supported
and well known.


Seems like Java may well be used on the actual rover in the future:

Jim Sculley wrote:
<quote>
In any event this entire discussion has ignored the Realtime
Specification for Java, implementations of which are being used in
mission critical apps, such as control systems for a future Mars rover:

http://www.opengroup.org/rtforum/upl...den_Gate_May01
-v05.pdf

Jim S.
</quote>

l8r, Mike N. Christoff

Jul 17 '05 #41

P: n/a
Jan C. Vorbrüggen <jv**********@mediasec.de> writes:
For any modern compiler of a 3GL language, not compiling with (the equivalent
of) -fast is grossly negligent.


A few years ago, I was asked to help with improving the performance of
a major production code here. The author of the code didn't even
know how to turn on the optimizer. I mean turning on the optimizer
at all, even with a simple -O, much less experimenting with the other
settings. I was a bit shocked that they felt the need to call for
help and hadn't even tried that. This was from a supposedly
professional full-time programmer and was in a code that had gone
through all the formal development process (for what little that
was actually worth :-() and was in production use.

But then, I found plenty of other problems also. I suppose it
figures. :-(

It was a Fortran code, but the major problems didn't have much to
do with the language. If you are sufficiently clueless, you can
manage to express that cluelessness in any language.

--
Richard Maine | Good judgment comes from experience;
email: my first.last at org.domain | experience comes from bad judgment.
org: nasa, domain: gov | -- Mark Twain
Jul 17 '05 #42

P: n/a
Jan C. Vorbrüggen <jv**********@mediasec.de> writes:
For any modern compiler of a 3GL language, not compiling with (the equivalent
of) -fast is grossly negligent.


A few years ago, I was asked to help with improving the performance of
a major production code here. The author of the code didn't even
know how to turn on the optimizer. I mean turning on the optimizer
at all, even with a simple -O, much less experimenting with the other
settings. I was a bit shocked that they felt the need to call for
help and hadn't even tried that. This was from a supposedly
professional full-time programmer and was in a code that had gone
through all the formal development process (for what little that
was actually worth :-() and was in production use.

But then, I found plenty of other problems also. I suppose it
figures. :-(

It was a Fortran code, but the major problems didn't have much to
do with the language. If you are sufficiently clueless, you can
manage to express that cluelessness in any language.

--
Richard Maine | Good judgment comes from experience;
email: my first.last at org.domain | experience comes from bad judgment.
org: nasa, domain: gov | -- Mark Twain
Jul 17 '05 #43

P: n/a
Richard Maine <no****@see.signature> writes:
If you are sufficiently clueless, you can manage to express that
cluelessness in any language.


I think this is a quote worthy of a .sig file. (I'm assuming this is a
Richard Maine original?)

---------------------------------------------------------------------
| "Good and evil both increase at compound
Ben Hocking, Grad Student | interest. That is why the little
ho*****@cs.virginia.edu | decisions you and I make every day are of
| such infinite importance." - C. S. Lewis
---------------------------------------------------------------------
Jul 17 '05 #44

P: n/a
Richard Maine <no****@see.signature> writes:
If you are sufficiently clueless, you can manage to express that
cluelessness in any language.


I think this is a quote worthy of a .sig file. (I'm assuming this is a
Richard Maine original?)

---------------------------------------------------------------------
| "Good and evil both increase at compound
Ben Hocking, Grad Student | interest. That is why the little
ho*****@cs.virginia.edu | decisions you and I make every day are of
| such infinite importance." - C. S. Lewis
---------------------------------------------------------------------
Jul 17 '05 #45

P: n/a
In article <40***************@Sonnack.com>, Ch***@Sonnack.com says...
seemanta dutta wrote:
of course by increasing the velocity several times we can generate
some lift, but that would be a totally wasteful use of energy.


One can also increase wing area. This is, e.g., why 747s can land
so amazingly slowly for such a big bird.


Flaps and slats (particularly on large aircraft) make a huge difference.

This is somewhat interesting, although the animation is fairly weak.
http://www.grc.nasa.gov/WWW/K-12/airplane/flap.html

During takeoff and landing the airplane's velocity is relatively low.
To keep the lift high (to avoid objects on the ground!), airplane designers
try to increase the wing area and change the airfoil shape by putting some
moving parts on the wings' leading and trailing edges. The part on the leading
edge is called a slat, while the part on the trailing edge is called a flap.
The flaps and slats move along metal tracks built into the wings. Moving the
flaps aft (toward the tail) and the slats forward increases the wing area.
Pivoting the leading edge of the slat and the trailing edge of the flap
downward increases the effective camber of the airfoil, which increases the
lift. In addition, the large aft-projected area of the flap increases the drag
of the aircraft. This helps the airplane slow down for landing.
--
Randy Howard
2reply remove FOOBAR

Jul 17 '05 #46

P: n/a
In article <40***************@Sonnack.com>, Ch***@Sonnack.com says...
seemanta dutta wrote:
of course by increasing the velocity several times we can generate
some lift, but that would be a totally wasteful use of energy.


One can also increase wing area. This is, e.g., why 747s can land
so amazingly slowly for such a big bird.


Flaps and slats (particularly on large aircraft) make a huge difference.

This is somewhat interesting, although the animation is fairly weak.
http://www.grc.nasa.gov/WWW/K-12/airplane/flap.html

During takeoff and landing the airplane's velocity is relatively low.
To keep the lift high (to avoid objects on the ground!), airplane designers
try to increase the wing area and change the airfoil shape by putting some
moving parts on the wings' leading and trailing edges. The part on the leading
edge is called a slat, while the part on the trailing edge is called a flap.
The flaps and slats move along metal tracks built into the wings. Moving the
flaps aft (toward the tail) and the slats forward increases the wing area.
Pivoting the leading edge of the slat and the trailing edge of the flap
downward increases the effective camber of the airfoil, which increases the
lift. In addition, the large aft-projected area of the flap increases the drag
of the aircraft. This helps the airplane slow down for landing.
--
Randy Howard
2reply remove FOOBAR

Jul 17 '05 #47

P: n/a
Randy Howard wrote:
One can also increase wing area. This is, e.g., why 747s can land
so amazingly slowly for such a big bird.
Flaps and slats (particularly on large aircraft) make a huge
difference.


One reason they make a diff on large aircraft is the proportional
difference in increasing the wing area of an already large wing.

Keep in mind that ALL aircraft land with flaps. 747s are slower
because their wings are bigger to begin with.
[quote]
...To keep the lift high (to avoid objects on the ground!), airplane
designers try to increase the wing area and change the airfoil shape
...


Yep. Airfoil shape is another mechanism. High camber affects
performance, so isn't used other than at slow speeds (IIUC).
Compare this to fighter jets with itty bitty razor-sharp wings.
Those babies need serious speed to fly at all!

--
|_ CJSonnack <Ch***@Sonnack.com> _____________| How's my programming? |
|_ http://www.Sonnack.com/ ___________________| Call: 1-800-DEV-NULL |
|_____________________________________________|___ ____________________|
Jul 17 '05 #48

P: n/a
Randy Howard wrote:
One can also increase wing area. This is, e.g., why 747s can land
so amazingly slowly for such a big bird.
Flaps and slats (particularly on large aircraft) make a huge
difference.


One reason they make a diff on large aircraft is the proportional
difference in increasing the wing area of an already large wing.

Keep in mind that ALL aircraft land with flaps. 747s are slower
because their wings are bigger to begin with.
[quote]
...To keep the lift high (to avoid objects on the ground!), airplane
designers try to increase the wing area and change the airfoil shape
...


Yep. Airfoil shape is another mechanism. High camber affects
performance, so isn't used other than at slow speeds (IIUC).
Compare this to fighter jets with itty bitty razor-sharp wings.
Those babies need serious speed to fly at all!

--
|_ CJSonnack <Ch***@Sonnack.com> _____________| How's my programming? |
|_ http://www.Sonnack.com/ ___________________| Call: 1-800-DEV-NULL |
|_____________________________________________|___ ____________________|
Jul 17 '05 #49

P: n/a
Ashlie Benjamin Hocking wrote:
Richard Maine <no****@see.signature> writes:
If you are sufficiently clueless, you can manage to express that
cluelessness in any language.
I think this is a quote worthy of a .sig file. (I'm assuming this is a
Richard Maine original?)


It bears a relation to "Real Programmers can write Fortran in any
language", but I hesitate to call it a "corollary".

[ dodges ]

--
Toon Moene - mailto:to**@moene.indiv.nluug.nl - phoneto: +31 346 214290
Saturnushof 14, 3738 XG Maartensdijk, The Netherlands
Maintainer, GNU Fortran 77: http://gcc.gnu.org/onlinedocs/g77_news.html
GNU Fortran 95: http://gcc.gnu.org/fortran/ (under construction)

Jul 17 '05 #50

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