From: karpf@sartre.wro.dec.com (Len Karpf)
Newsgroups: comp.ai.shells
Subject: Re: G2 - Real-time expert system
Date: 2 Sep 92 16:12:45 GMT
Reply-To: karpf@sartre.wro.dec.com (Len Karpf)
Organization: Digital Equipment Corporation


In article <1992Sep2.111639.3470@fel.tno.nl>, leeh7@fel.tno.nl (Ed van Leeuwen) writes:
|> Path: pa.dec.com!decwrl!olivea!uunet!mcsun!sun4nl!tnofel!leeh7
|> From: leeh7@fel.tno.nl (Ed van Leeuwen)
|> Newsgroups: comp.ai.shells
|> Subject: G2 - Real-time expert system
|> Message-ID: <1992Sep2.111639.3470@fel.tno.nl>
|> Date: Wed, 2 Sep 92 04:16:39 GMT+8:00
|> Organization: TNO Physics and Electronics Laboratory
|> Lines: 26
|> 
|> Dear reader,
|> 
|> We have had some information and a demonstration of the
|> real-time expert system shell G2. It looks impressive
|> but I would like to have some information of users who
|> have already had some experience with this shell.
|> 
|> Please send me you brief working experience.
|> Thanks in advance.
|> 
|> Should anyone have any information on other real-time expert
|> system shells, I would be grateful if they should reply as well.
|> 
|> 
|> 
|> 					Regards,
|> 
|> 					Ed.
|> 
|> ===============================================================================
|> Ed van Leeuwen                        |  Ed W.A. van Leeuwen
|> FEL-TNO                               |  TNO Physics and Electronics Laboratory
|> 's-Gravenhage                         |  The Hague, the Netherlands
|> -------------------------------------------------------------------------------
|> Ed.van.Leeuwen@fel.tno.nl             |  WARNING: do not feed the lions
|> ===============================================================================
|> 


I have just finished a 2 year project using G2.  It was a real-time expert system that controls production in an automobile plant.  We developed most of the application in version 2.1, and delivered in the *beta* of version 3.0.  I know the tool pretty well, so I think that I can give you a few pointers.  

Be advised that Gensym's definition of real-time and your definition of real time may not be the same.  If you are receiving sensor data from a single sensor more than once a second, you're going to have to do some pretty fancy footwork to cope with the data.  Furthermore, G2 code is interpreted and cannot be compiled for run time delivery.  Therefore, you will always have a performace hit.  G2's garbage collector cannot be externally controlled, and it seems to get hung up at times.  That it not a desirab





le feature for a real-time application.

The developer's interface is poor.  It can be a chore to get things done.  Its editor does not even have such basic functions such as search, replace, and scrolling.

The claim that the system is object-oriented is a great stretch - G2's object representation much more closely resembles Pascal records than it does the Smalltalk model.

G2's hooks to the outside world, via its GSI module, are quite rudimentary.  GSI is written in C and that is really the only language that it will support.

If you want more information, you can contact me directly.  We are currently looking at other real-time tools such as RTworks from Talarian, but that's the only other tool that we've found so far that claims to be real-time.
			    Len Karpf
			    karpf@sartre.wro.dec.com

			    *The opinions expressed are my own.*
Newsgroups: comp.ai.shells