Re: Mars Rover Controlled By Java
From: Michael N. Christoff (mchristoff_at_sympatico.caREMOVETHIS)
Date: 01/22/04
- Next message: Michael N. Christoff: "Re: Mars Rover Controlled By Java"
- Previous message: Marc Dzaebel: "Re: reinitialize byte array to zero"
- In reply to: Harry Conover: "Re: Mars Rover Controlled By Java"
- Next in thread: Michael N. Christoff: "Re: Mars Rover Controlled By Java"
- Reply: Michael N. Christoff: "Re: Mars Rover Controlled By Java"
- Reply: Jan C. Vorbrüggen: "Re: Mars Rover Controlled By Java"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Date: Wed, 21 Jan 2004 19:46:59 -0500
"Harry Conover" <hhc314@yahoo.com> wrote in message
news:7ce4e226.0401211406.5858d3e7@posting.google.com...
> "Michael N. Christoff" <mchristoff@sympatico.caREMOVETHIS> wrote in
message news:<ZCZNb.8151$c1.1022393@news20.bellglobal.com>...
> > 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_3-5142220.html?tag=nefd_top
>
>
> 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 misrepresentation of Java's
> capabilities, potentially at Sun's credibility expense.
>
a) the article never said that Java was on the rover itself. b) Java is
more than a language, it is a platform. c) the fact that Java needs an
underlying OS has never been disputed by anyone. The idea is for Java to be
portable to other _already developed_ platforms. It would not be very
portable if you had to dual boot into a Java OS to run Java apps. d) There
is no reason to believe a real time system cannot be virtual machine based.
It is technicaly feasible and all the benefits of seperating code from
hardware/OS are just as relevant on embedded systems as they are on
desktops. Just look at cell phones. (note: many many people laughed at the
idea that something as small as a cell-phone could run any VM-based
language. Java on top of VM on top of embedded OS seemed way too bulky to
ever be practical. But Moore's law apparently does not apply only to
desktops, but even embedded devices). Will a real-time Java have all the
features of regular Java? Doubtful. ie: automatic garbage collection may
not be possible.
l8r, Mike N. Christoff
- Next message: Michael N. Christoff: "Re: Mars Rover Controlled By Java"
- Previous message: Marc Dzaebel: "Re: reinitialize byte array to zero"
- In reply to: Harry Conover: "Re: Mars Rover Controlled By Java"
- Next in thread: Michael N. Christoff: "Re: Mars Rover Controlled By Java"
- Reply: Michael N. Christoff: "Re: Mars Rover Controlled By Java"
- Reply: Jan C. Vorbrüggen: "Re: Mars Rover Controlled By Java"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Relevant Pages
|
