Re: EMC for DOS?

To answer the multitasking question let's focus very narrow and compare
the EMC running under Linux or under dos. No extraneous stuff about
fanuc or anyone else. And no stuff about playing pysol card games or
downloading porn.

EMC as it runs under realtime Linux uses several processes at the same
time all by itself. At least four big ones come to mind for my minimill.
There is the free running interpreter sitting there pumping about 200
blocks beyond the executing one into the task program. The task program,
also free running, is where the major coordination of all elements of
your machine takes place. Then there is the motion module which kinda
free runs but is time deterministic.

The big multitasker is the Graphical User Interface. Here I can run a
lot of the EMC with a single program like xemc, tkemc, or tkemcex but if
I want to edit the tool table, the parameters, or the part program, or
tune on the machine or log machine motion, or watch the parport or I/O
logic each is a separate process running under some combination of linux
and real time linux.

With a single path OS like dos you have to build into your CNC software
the ability to hook in these peripheral tasks without trashing the main
job of keeping the machine moving in a safe, coordinated manner. Just
showing the ladder logic can be a major diversion for a single tasking os.

So my answer to the why multitask question is that it allows you to do
many of the things that members of this list want their machines to do.
Want a push button operator panel -- add a task and you're there. Yes
you can add the same panel with a dos version but you will have to do a
bunch of coding.

HTH

RayH -- U.P. Michigan

>    From: "stevenson_engineers" <machines@...>
> Subject: Re: EMC for DOS?

<s>

> Why does everybody place such importance on this muli tasking.
> Old computers for shop use are 10 a penny now.
> I can't imagine anybody doing any serious work risking many hours of
> machining because there is a gltch whilst you are playing on the
> internet  and your CNC's doing a job.