Mars Rover Controlled By Java

[Randy Howard]

Re: Mars Rover Controlled By Java

In article <400EABC4.B2899 20A@Sonnack.com >, Chris@Sonnack.c om says...[color=blue]
> seemanta dutta wrote:
>[color=green]
> > of course by increasing the velocity several times we can generate
> > some lift, but that would be a totally wasteful use of energy.[/color]
>
> One can also increase wing area. This is, e.g., why 747s can land
> so amazingly slowly for such a big bird.[/color]

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

[Randy Howard]

Re: Mars Rover Controlled By Java

In article <400EABC4.B2899 20A@Sonnack.com >, Chris@Sonnack.c om says...[color=blue]
> seemanta dutta wrote:
>[color=green]
> > of course by increasing the velocity several times we can generate
> > some lift, but that would be a totally wasteful use of energy.[/color]
>
> One can also increase wing area. This is, e.g., why 747s can land
> so amazingly slowly for such a big bird.[/color]

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

[Programmer Dude]

Re: Mars Rover Controlled By Java

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

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.
[color=blue]
> [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
> ...[/color]

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 <Chris@Sonnack. com> _____________| How's my programming? |
|_ http://www.Sonnack.com/ _______________ ____| Call: 1-800-DEV-NULL |
|______________ _______________ _______________ _|_____________ __________|

[Programmer Dude]

Re: Mars Rover Controlled By Java

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

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.
[color=blue]
> [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
> ...[/color]

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 <Chris@Sonnack. com> _____________| How's my programming? |
|_ http://www.Sonnack.com/ _______________ ____| Call: 1-800-DEV-NULL |
|______________ _______________ _______________ _|_____________ __________|

[Toon Moene]

Re: Mars Rover Controlled By Java

Ashlie Benjamin Hocking wrote:
[color=blue]
> Richard Maine <nospam@see.sig nature> writes:
>[color=green]
>>If you are sufficiently clueless, you can manage to express that
>>cluelessnes s in any language.[/color][/color]
[color=blue]
> I think this is a quote worthy of a .sig file. (I'm assuming this is a
> Richard Maine original?)[/color]

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:toon@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)

[Toon Moene]

Re: Mars Rover Controlled By Java

Ashlie Benjamin Hocking wrote:
[color=blue]
> Richard Maine <nospam@see.sig nature> writes:
>[color=green]
>>If you are sufficiently clueless, you can manage to express that
>>cluelessnes s in any language.[/color][/color]
[color=blue]
> I think this is a quote worthy of a .sig file. (I'm assuming this is a
> Richard Maine original?)[/color]

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:toon@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)

[Harry Conover]

Re: Mars Rover Controlled By Java

"Michael N. Christoff" <mchristoff@sym patico.caREMOVE THIS> wrote in message news:<ZCZNb.815 1$c1.1022393@ne ws20.bellglobal .com>...[color=blue]
> 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[/color]


Mike, I have no facts to support this, but my guess is that that the
PR blurb you post is little more than a bit of marketing spin whose
quotes are being read out of context by a few Java enthusiasts.

First of all, obviously Java is not an operating system. It's an
application programming language or tool targeted to the production of
Internet (particularly browser applications). You also cannot
implement a true operating system using Java as your programming
language. If you doubt this, I'll hand you an 80586 chip with 128-Megs
of online memory and chuckle as you try!)

Java is absolutely useless except when running on a platform already
equipped with an operating system, and many layers of data
communications and application programs, where the top levels include
an operating TCP/IP stack and browser software.

Almost certainly the OS within the rover is a highly optimized
real-time kernel likely programmed in assembler, C, C++ or some other
system implementation langage. (Perhaps even Ada, although that would
be a long-shot.) Java is certainly not a member of this tight-knit
club of system implementation languages, and I simply cannot picture
anyone even attempting to implement a real-time OS using it. Java is
not running the Rover, its real-time operating system is.

My guess is that when you get details of the facts supporting this PR
release, you'll learn that certain Java apps form a portion of the
man-machine interface design employed for the entry of command
sequences here on earth, since Java is capable of simpllifying the
design of this type of software over what could otherwise be
programmed using xlib, C, C++ or even (gasp) assembly language, since
the programming of a control entry MMI is today not exactly rocket
science (no pun intended). (Heck, you could probably even use Visual
Basic for the purpose, if really desperate! Back in the early days of
surveilance satellites, we even programmed the ground based command
interpreters for the K-series birds using Fortran, and they were both
trivial to program and functioned perfectly.)

Also, at last count the foundations of the Internet rested heavily on
C/C++/Assembler implementations running on Unix platforms, however
this may or may not have changed over the years. (At last count, the
thousands of different routines supporting operation of the Internet
involved the use of nearly as many different programming tools...since
so long as they all result in the production of really tight, robust,
executable machine code, the choice of programming language really
doesn't matter.)

When a firm intentionally confuses application programming tools such
as Java with real-time OS implementation methodoloy, in my mind they
both risk and deserve justifiable ridicule. I don't believe that Sun
intended to create such confusion in their publicity release, however
a few Java enthusiasts do seem bent on misrepresentati on of Java's
capabilities, potentially at Sun's credibility expense.

Harry C.

[Harry Conover]

Re: Mars Rover Controlled By Java

"Michael N. Christoff" <mchristoff@sym patico.caREMOVE THIS> wrote in message news:<ZCZNb.815 1$c1.1022393@ne ws20.bellglobal .com>...[color=blue]
> 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[/color]


Mike, I have no facts to support this, but my guess is that that the
PR blurb you post is little more than a bit of marketing spin whose
quotes are being read out of context by a few Java enthusiasts.

First of all, obviously Java is not an operating system. It's an
application programming language or tool targeted to the production of
Internet (particularly browser applications). You also cannot
implement a true operating system using Java as your programming
language. If you doubt this, I'll hand you an 80586 chip with 128-Megs
of online memory and chuckle as you try!)

Java is absolutely useless except when running on a platform already
equipped with an operating system, and many layers of data
communications and application programs, where the top levels include
an operating TCP/IP stack and browser software.

Almost certainly the OS within the rover is a highly optimized
real-time kernel likely programmed in assembler, C, C++ or some other
system implementation langage. (Perhaps even Ada, although that would
be a long-shot.) Java is certainly not a member of this tight-knit
club of system implementation languages, and I simply cannot picture
anyone even attempting to implement a real-time OS using it. Java is
not running the Rover, its real-time operating system is.

My guess is that when you get details of the facts supporting this PR
release, you'll learn that certain Java apps form a portion of the
man-machine interface design employed for the entry of command
sequences here on earth, since Java is capable of simpllifying the
design of this type of software over what could otherwise be
programmed using xlib, C, C++ or even (gasp) assembly language, since
the programming of a control entry MMI is today not exactly rocket
science (no pun intended). (Heck, you could probably even use Visual
Basic for the purpose, if really desperate! Back in the early days of
surveilance satellites, we even programmed the ground based command
interpreters for the K-series birds using Fortran, and they were both
trivial to program and functioned perfectly.)

Also, at last count the foundations of the Internet rested heavily on
C/C++/Assembler implementations running on Unix platforms, however
this may or may not have changed over the years. (At last count, the
thousands of different routines supporting operation of the Internet
involved the use of nearly as many different programming tools...since
so long as they all result in the production of really tight, robust,
executable machine code, the choice of programming language really
doesn't matter.)

When a firm intentionally confuses application programming tools such
as Java with real-time OS implementation methodoloy, in my mind they
both risk and deserve justifiable ridicule. I don't believe that Sun
intended to create such confusion in their publicity release, however
a few Java enthusiasts do seem bent on misrepresentati on of Java's
capabilities, potentially at Sun's credibility expense.

Harry C.

[Harry Conover]

Re: Mars Rover Controlled By Java

mitch <realtime@-no-spam-acm.org> wrote in message news:<100hlnoe2 l8lp85@corp.sup ernews.com>...[color=blue]
> 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[/color]

Now that I can believe! :-)

I'm still supporting embedded 8051 packages running on the original
Franklin RTOS, nearly all embedded control systems using the Intel
80X86 family now run VxWorks, with the exception of the 80186. Wind
River is certainly doing something right.

Their VxWorks RTOS package is really slick...I know this because I was
once comissioned to write a RTOS OS for the 80186 similar to VxWorks
(which doesn't support the 80186 in order to provide support for a
legacy PLC controller design. Sadly, the firm quickly lost interest
and cancelled the funding 3-months into the project, just when I was
begining to become really good at rewriting VxWorks 80386 OS code into
80186 code! :-)

I never found out if the mission was scrubbed because of an internal
marketing decision, or because Wind River and its attorneys got wind
(no pun inteded) of the project.

What do/did you think of "Tornado"? Seemed to me that it was equally
as bad as "Starteam", and the neither of these two CM systems came
close to equaling the features provided by the old Unix PWB (for you
newbies, PWB "Programmer s Workbench", arguably the original software
configuration management tool).

Harry C.

[Harry Conover]

Re: Mars Rover Controlled By Java

mitch <realtime@-no-spam-acm.org> wrote in message news:<100hlnoe2 l8lp85@corp.sup ernews.com>...[color=blue]
> 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[/color]

Now that I can believe! :-)

I'm still supporting embedded 8051 packages running on the original
Franklin RTOS, nearly all embedded control systems using the Intel
80X86 family now run VxWorks, with the exception of the 80186. Wind
River is certainly doing something right.

Their VxWorks RTOS package is really slick...I know this because I was
once comissioned to write a RTOS OS for the 80186 similar to VxWorks
(which doesn't support the 80186 in order to provide support for a
legacy PLC controller design. Sadly, the firm quickly lost interest
and cancelled the funding 3-months into the project, just when I was
begining to become really good at rewriting VxWorks 80386 OS code into
80186 code! :-)

I never found out if the mission was scrubbed because of an internal
marketing decision, or because Wind River and its attorneys got wind
(no pun inteded) of the project.

What do/did you think of "Tornado"? Seemed to me that it was equally
as bad as "Starteam", and the neither of these two CM systems came
close to equaling the features provided by the old Unix PWB (for you
newbies, PWB "Programmer s Workbench", arguably the original software
configuration management tool).

Harry C.

[Harry Conover]

Re: Mars Rover Controlled By Java

Richard Maine <nospam@see.sig nature> wrote in message news:<m3isj55ji f.fsf@altair.df rc.nasa.gov>...[color=blue]
> Jan C. Vorbrüggen <jvorbrueggen@m ediasec.de> writes:
>[color=green]
> > For any modern compiler of a 3GL language, not compiling with (the equivalent
> > of) -fast is grossly negligent.[/color]
>
> 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.[/color]

If he was dealing with embedded software, the original designer may
have had good reason not to turn on the optimizer.

In embedded software, we frequently write to memory addresses that are
in turn mapped to hardware control registers. Early optimizer design
was frequently done by software folk not familiar with this practices,
often optimizing out writes to address that they didn't see being
later read.

IIRC, Microsoft's "MASM" was an assembler whose optimization exhibited
this defect. Today, no many people use MASM, so I don't know if the
flaw was ever corrected. As a result, many embedded software/firmware
designers today still operate with the optimizer turned off for
"safety", and prefer to optimize their own code.

Franklin's 8051 development suite initially exhibied the same problem,
but given that their target market was entired embedded software
designers, the problem was corrected by the 2nd release of the
product.
[color=blue]
> 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.[/color]

Amen to that statement, and suggest that it be etched it in stone.

A skilled programmer can even write in GWBASIC and produce fantastic
results through the clever use of (IIRC) PUT and POKE commands, which
allow the insertion of machine language instructions in the GWBASIC or
the Atari BASIC command stream. (I wonder how many of today's
programmers would be resouceful enough to use of such extreme
techniques to achieve their goals? Heck, for that matter how many have
ever even directly used machine code?)

Harry C.

[Harry Conover]

Re: Mars Rover Controlled By Java

Richard Maine <nospam@see.sig nature> wrote in message news:<m3isj55ji f.fsf@altair.df rc.nasa.gov>...[color=blue]
> Jan C. Vorbrüggen <jvorbrueggen@m ediasec.de> writes:
>[color=green]
> > For any modern compiler of a 3GL language, not compiling with (the equivalent
> > of) -fast is grossly negligent.[/color]
>
> 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.[/color]

If he was dealing with embedded software, the original designer may
have had good reason not to turn on the optimizer.

In embedded software, we frequently write to memory addresses that are
in turn mapped to hardware control registers. Early optimizer design
was frequently done by software folk not familiar with this practices,
often optimizing out writes to address that they didn't see being
later read.

IIRC, Microsoft's "MASM" was an assembler whose optimization exhibited
this defect. Today, no many people use MASM, so I don't know if the
flaw was ever corrected. As a result, many embedded software/firmware
designers today still operate with the optimizer turned off for
"safety", and prefer to optimize their own code.

Franklin's 8051 development suite initially exhibied the same problem,
but given that their target market was entired embedded software
designers, the problem was corrected by the 2nd release of the
product.
[color=blue]
> 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.[/color]

Amen to that statement, and suggest that it be etched it in stone.

A skilled programmer can even write in GWBASIC and produce fantastic
results through the clever use of (IIRC) PUT and POKE commands, which
allow the insertion of machine language instructions in the GWBASIC or
the Atari BASIC command stream. (I wonder how many of today's
programmers would be resouceful enough to use of such extreme
techniques to achieve their goals? Heck, for that matter how many have
ever even directly used machine code?)

Harry C.

[Alan Balmer]

Re: Mars Rover Controlled By Java

On 21 Jan 2004 14:06:56 -0800, hhc314@yahoo.co m (Harry Conover) wrote:
[color=blue]
>"Michael N. Christoff" <mchristoff@sym patico.caREMOVE THIS> wrote in message news:<ZCZNb.815 1$c1.1022393@ne ws20.bellglobal .com>...[color=green]
>> 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[/color]
>
>
>Mike, I have no facts to support this, but my guess is that that the
>PR blurb you post is little more than a bit of marketing spin whose
>quotes are being read out of context by a few Java enthusiasts.
>[/color]
You're about four days late with this observation ;-) Folks who
actually read the referenced article, "Java runs remote-controlled
Mars rover", learned that while a Java program "runs" a simulated
rover, here on earth, and is a very useful tool for mission planning,
it does not run *on* the rover, or directly control it. Read the
article.

You can get the software at http://mars.telascience.org/

--
Al Balmer
Balmer Consulting
removebalmercon sultingthis@att .net

[Alan Balmer]

Re: Mars Rover Controlled By Java

On 21 Jan 2004 14:06:56 -0800, hhc314@yahoo.co m (Harry Conover) wrote:
[color=blue]
>"Michael N. Christoff" <mchristoff@sym patico.caREMOVE THIS> wrote in message news:<ZCZNb.815 1$c1.1022393@ne ws20.bellglobal .com>...[color=green]
>> 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[/color]
>
>
>Mike, I have no facts to support this, but my guess is that that the
>PR blurb you post is little more than a bit of marketing spin whose
>quotes are being read out of context by a few Java enthusiasts.
>[/color]
You're about four days late with this observation ;-) Folks who
actually read the referenced article, "Java runs remote-controlled
Mars rover", learned that while a Java program "runs" a simulated
rover, here on earth, and is a very useful tool for mission planning,
it does not run *on* the rover, or directly control it. Read the
article.

You can get the software at http://mars.telascience.org/

--
Al Balmer
Balmer Consulting
removebalmercon sultingthis@att .net

[Alan Balmer]

Re: Mars Rover Controlled By Java

On 21 Jan 2004 14:59:32 -0800, hhc314@yahoo.co m (Harry Conover) wrote:
[color=blue]
>A skilled programmer can even write in GWBASIC and produce fantastic
>results through the clever use of (IIRC) PUT and POKE commands, which
>allow the insertion of machine language instructions in the GWBASIC or
>the Atari BASIC command stream. (I wonder how many of today's
>programmers would be resouceful enough to use of such extreme
>techniques to achieve their goals?[/color]

Programmers tend to be as resourceful as necessary, to the detriment
of the remainder of the code's life cycle.. Fortunately, such
techniques are usually not necessary on today's programming platforms.
Unfortunately, some programmers use them anyway.
[color=blue]
> Heck, for that matter how many have
>ever even directly used machine code?)[/color]

Rarely needed, even in my day. Assembler language is much preferable,
and lots of people still use it. Direct use of machine code is (was)
sometimes useful for debugging and patching.

--
Al Balmer
Balmer Consulting
removebalmercon sultingthis@att .net