Re: Can EMC be run accross two PC's

[Ray <rehenry-at-up.net>]

Woody, Tom, John

Uh, yea.  I put copies of some posts re this at;

file:/home/ray/handbook/part3/customizing/remoteg.html

I haven't tried a black box linux yet but I plan to show one off at NAMES
in three months.  NIST sees NML as a fully capable real time communication
system.  They say;

"To achieve efficient communication between distributed real-time
processes, it is desirable to both choose the best protocol for each
ommunication path and limit variation to improve software portability.
These divergent goals can be satisfied through the use of a uniform
pplication programming interface (API) that hides the details of specific
protocols from programmers. The Neutral Message Language (NML) is a
uniform API to communication functions that includes many popular
protocols: interprocess shared memory; interprocessor backplane global
memory; and Internet networking. NML implements a mailbox model for
ommunication, with both queued- and non-queued access, blocking- and
non-blocking reads and writes, and multiple readers and writers. NML
provides language bindings for both C++ and Java. The protocol
parameters are contained in configuration files that are read at run time, so
hat a system's allocation of processes to processors can be deferred as late
s desired and modified dynamically. NML handles mutual exclusion for
data integrity, and converts between native machine format and neutral
data encoding when necessary."

William P. Shackleford, Frederick M. Proctor, and John L. Michaloski
National Institute of Standards and Technology
ABSTRACT
--

Now since most all of the EMC communicates using NML you should be able to
split up the task most any place.  So long as the NML channels exist
between processors the EMC should not care where the tasks start, how they
pipe, or where they end.

Perhaps we would like to share this task by selecting a common SBC and
some other hardware.  I've done some looking at pc104 but a pentium based
SBC seems like it would do the job at lower cost but without the hassle of
changing mother boards more often than some change socks.

Thanks for bringing this up.
--

Ray


On Fri, 08 Dec 2000, Woody wrote:
> (Dang, I've unlurked and now I can't stop...)
> 
> If you look at the NIST EMC/RCS/NML stuff, they claim this should be
> a 'feature' using something like TCP/IP/UDP and modifying the NML
> configuration.  I'd be _real_ interested if someone has (or would) try this.
> 
> I'm _VERY_ new to EMC and still struggling with RCS/NML and haven't
> taken more than the cursory look at the division of duties between io,
> mot and task.
> 
> If anybody could throw me some detailed info on that sort of thing and
> perhaps how the UI interfaces with EMC (i'm definitely not a Tkl guru),
> maybe a tutorial for us all that would be most excellent.
> 
> -Woody
> 
> ----- Original Message -----
> From: John Guenther <jguenthe-at-nafis.fp.trw.com>
> To: Multiple recipients of list <emc-at-nist.gov>
> Sent: Friday, December 08, 2000 11:39 AM
> Subject: Can EMC be run accross two PC's
> 
> 
> >
> > Hi All,
> >
> > Here is my question, can EMC be split up and run on two PC's?  The idea
> > is to put the emcio and emcmot functions on a dedicated processor, maybe
> > even a single board computer running LInux.  I would then be running the
> > emctask functions, the gui and what ever else on another computer.
> > Connection between the two computers would / could be by high speed
> > serial interface.
> >
> > My theory is that this might allow the emctask functions to be performed
> > by a Windoze computer with a familiar user interface.  The time critical
> > and complicated functions would be performed on a dedicated computer
> > running rt-linux.