Subject:
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Re: Something else is needed, I think...
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 4 May 1999 17:22:08 GMT
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Original-From:
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John A. Tamplin <jat@AVOIDSPAMliveonthenet.com>
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Viewed:
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1016 times
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On Tue, 4 May 1999, Sren Hilmer wrote:
> I say Java is the way to go, actually I am planning to do a JVM for the RCX.
> The JVM is not necessarily complex, It is possible to do a subset, SUN already
> does that with the JavaCard specification (that is Java running on smartcards).
> This specification rules out things like floats, ints, Strings, Threads,
> garbage collection, ...
> some of them we probably need to put back in like threads (and maybe gc).
JavaCard is highly specialized to a SmartCard application. As far as I know,
the only way to communicate with a JavaCard interpreter is through the ISO
APDU mechanism. You also don't have computation running in the background,
since applets only respond to select and process methods.
> And like in the JavaCard specification some of the stuff that comprise the JVM
> does not need to run on the target computer (RCX in our case), the bytecode
> verifier and the resolver can be run on the computer which downloads the
> classes to the target (the specification does not require dynamic class loading
> either).
EmbeddedJava doesn't require dynamic class loading, but if you do have a
way of loading classes the bytecode verifier must be present. In JavaCard,
there is an additional step of verifying the bytecode is a JavaCard subset
and compressing it.
> I have been using five different implementations of the JavaCard specification
> by now, and they all seems to work really well.
Which ones are these? I am using the JC2.0 which is implemented by the
iButton with Java.
John A. Tamplin Traveller Information Services
jat@LiveOnTheNet.COM 2104 West Ferry Way
256/705-7007 - FAX 256/705-7100 Huntsville, AL 35801
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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Message has 1 Reply:
 | | Re: Something else is needed, I think...
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| (...) already (...) smartcards). (...) That is right, but this is mainly enforced by the class library, which offcourse will have to be way different for the RCX. What I was getting at was that we do not need to implement the whole java bytecode (...) (25 years ago, 5-May-99, to lugnet.robotics)
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Message is in Reply To:
| | Re: Something else is needed, I think...
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| (...) I say Java is the way to go, actually I am planning to do a JVM for the RCX. The JVM is not necessarily complex, It is possible to do a subset, SUN already does that with the JavaCard specification (that is Java running on smartcards). This (...) (25 years ago, 4-May-99, to lugnet.robotics)
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