Java in a chip? JAM (Java Actual Machine)?

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Ramon F Herrera - 27 Nov 2007 04:22 GMT

One can't help but wonder: what has prevented folks from making Java
run directly in its own hardware...

Is there anything inherent in the language that prevents it from being
compiled or even chiseled on silicon?

-Ramon

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Manish Pandit - 27 Nov 2007 04:29 GMT

> One can't help but wonder: what has prevented folks from making Java
> run directly in its own hardware...
[quoted text clipped - 3 lines]
>
> -Ramon

Looks like they tried, back in good ol' 1998 and gave up.

http://www.javaworld.com/javaworld/jw-11-1998/jw-11-idgns-javachip.html

-cheers,
Manish

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mich - 27 Nov 2007 15:38 GMT

>> One can't help but wonder: what has prevented folks from making Java
>> run directly in its own hardware...
[quoted text clipped - 7 lines]
>
> http://www.javaworld.com/javaworld/jw-11-1998/jw-11-idgns-javachip.html

Interesting; why not have a "java" card that can just be installed in a
computer. Would that really speed up a java program?

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Hunter Gratzner - 27 Nov 2007 07:10 GMT

> One can't help but wonder: what has prevented folks from making Java
> run directly in its own hardware...

Nothing. People have done it and still do it. But the customers are
not really keen for these chips and some vendors are to stupid to
market them properly.

> Is there anything inherent in the language that prevents it from being
> compiled or even chiseled on silicon?

No. Many did, some still do. Among the more known are the following
two.

Azul Systems builds Java "supercomputers" based on their own Vega
chip. And got in trouble with Sun about patents.

ARM sells ARM processors with Jazell DBX (Direct Bytecode eXecution).
The problem? Once again intellectual property rights. You need to
obtain a special license from ARM in order to be allowed to execute
the particular machine instruction on an ARM processor that enables
Jazell. Sun's J2ME ARM reference implementation suffers from this. To
quote from http://java.sun.com/javame/reference/docs/cldc-hi-2.0-web/doc/release/CLDC_HI-re
lease-notes.html

"This confidential and proprietary software may be used for evaluation
or testing purposes for internal use only. Any commercial use requires
execution of a separate JTEK licensing agreement from ARM Limited.

This is in addition to any license agreement the licensor may have
entered into with Sun. For the avoidance of doubt, distribution of
products containing software code to exercise the BXJ instruction and
enable the use of the ARM Jazelle architecture extension without a
JTEK licensing agreement from ARM is expressly forbidden."

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Martin Gregorie - 27 Nov 2007 16:17 GMT

>> One can't help but wonder: what has prevented folks from making Java
>> run directly in its own hardware...
[quoted text clipped - 13 lines]
>
> ARM sells ARM processors with Jazell DBX (Direct Bytecode eXecution).

[ property rights stuff snipped]

There's another Java-based embedded system: the Parallaxes Javelin STAMP:

http://www.parallax.com/ProductInfo/Microcontrollers/tabid/121/Default.aspx

It uses a pretty heavily modified version of Java 1.2. The Javelin is a
micro PCB that fits in a 24 pin DIL socket, so there's no point in
having any GUI stuff, but OTOH it has been extended to deal with digital
signal lines, serial I/O and A<->D conversion. In summary, the language
subsetting involves:
    single thread only
    no GC
    no Interfaces (only abstract classes)
    subset of primitive data types (boolean, char, byte, 8 and 16
                     bit ints)
subset of the class library
     1-dimensional arrays
     Strings are ASCII, not unicode.

However, there seem to be no licensing issues.

The Javelin is pin-compatible with the BS2 BASIC stamp and, for that
matter, as the BASIC is an integer basic subset with hardware specific
extensions to handle digital signal lines and serial i/o it looks as if
the subsetting and extensions applied to both Java and BASIC are quite
similar.

Signature

martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

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Roedy Green - 28 Nov 2007 05:54 GMT

On Mon, 26 Nov 2007 20:22:58 -0800 (PST), Ramon F Herrera
<ramon@conexus.net> wrote, quoted or indirectly quoted someone who
said :

>One can't help but wonder: what has prevented folks from making Java
>run directly in its own hardware...
>
>Is there anything inherent in the language that prevents it from being
>compiled or even chiseled on silicon?

See http://mindprod.com/jgloss/picojava.html

Signature

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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Java in a chip? JAM (Java Actual Machine)?

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