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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 18428
>
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
Jan C. Vorbrüggen <jv**********@m ediasec.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
Jan C. Vorbrüggen <jv**********@m ediasec.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
Richard Maine <no****@see.sig nature> 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.virg inia.edu | decisions you and I make every day are of
| such infinite importance." - C. S. Lewis
---------------------------------------------------------------------
Jul 17 '05 #44
Richard Maine <no****@see.sig nature> 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.virg inia.edu | decisions you and I make every day are of
| such infinite importance." - C. S. Lewis
---------------------------------------------------------------------
Jul 17 '05 #45
In article <40************ ***@Sonnack.com >, Ch***@Sonnack.c om 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
In article <40************ ***@Sonnack.com >, Ch***@Sonnack.c om 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
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
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
Ashlie Benjamin Hocking wrote:
Richard Maine <no****@see.sig nature> writes:
If you are sufficiently clueless, you can manage to express that
cluelessnes s 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**@moe ne.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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