[Gambas-user] Did anybody try to run stepper motors through paralel port

[nando]

I use Gambas for nearly real-time work
and it performs remarkably well, actually quite impressed.
Far better than VB
I have a data stream at 13.5 Kbps coming in from a remote modem
requiring immediate work and turn around output.
It might not seem like a fast stream, but the remote end requires a
response immediately otherwise there are resends.  It works!
Gambas 1.0.19 graphical, FC4, samba
Longest running time was about 420 days sans error.
Some rules to follow:
multiple core if you have it: good!
remove unneed cron jobs.
reduce overhead.
turn swap off.
Very clean efficient programming as possible
-Fernando


---------- Original Message -----------
From: Doriano Blengino <doriano.blengino at ...1909...>
To: mailing list for gambas users <gambas-user at lists.sourceforge.net>
Sent: Sun, 18 Apr 2010 23:07:55 +0200
Subject: Re: [Gambas-user] Did anybody try to run stepper motors through	paralel port

> Zelimir Ikovic ha scritto:
> > I wanted to know how predictable and reliable GAMBAS is when a reaction to real-world
events is required. 
> >
> > Let say that Java RealTimeSystem is intended only for suitable  operating systems,
which means that only a 
> > real-time operating system, such as QNX, is appropriate for implementing the JVM.
> > So that means it depends on underlynig OS version ...
> >  
> >  Simply installing an RTS extension 
> >  and renaming java.lang.Thread instances to 
> >  javax.realtime.RealtimeThread will not turn the 
> >  application into a real-time app.
> >  
> >  I just wanted to know what is Gamas reaction to real world compared under different
underlyng OS.
> >  FreeBSD, OpenBSD and Linux are not he same.
> >   
> I understand but, let me say, your sample code had nothing to do with 
> realtime... it was simply "fast as much as possible", without any 
> mechanism to ensure some kind of real-time response to some event. To 
> only read a counter is not enough. I can run 4 stepper motors directly 
> (no step+direction, but driving the phases directly instead) with a CPU 
> more than 100 times slower than a x86 CPU. But this is possible using 
> interrupts. Practically every OS can, in some way, use interrupts - 
> gambas can not. So, the only way in gambas to do precise timing is to 
> let it run alone, with maximum priority and privileges. Or, to delegate 
> high timing precision to some external piece of software (a libray or a 
> driver) which can take advantage of interrupts, or callbacks, or signals.
> 
> On the other hand I think that gambas can, with tight loops, do delays 
> like you did in the original source. Surely it is predictable enough to 
> let you calculate in some way the correct amount of cycling to obtain 
> the needed delay - the fact is that gambas will never be the only thing 
> running on the system, and you have little control about that. The same 
> problem of windows xp - if you want precise timing, you must obtain 
> privileges, either for the program or using a driver. I must also add 
> that, without particular precautions, linux is more predictable about 
> sleep() than win2000 or xp.
> 
> Regards,
> 
> -- 
> Doriano Blengino
> 
> "Listen twice before you speak.
> This is why we have two ears, but only one mouth."
> 
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------- End of Original Message -------