I have ported a few real time DOS programs to RT Linux and it is fairly easy once you
have the RT Linux machine setup. I won't go into all of the details of setting up the
Linux machine because there are many steps involved. However, the instructions are
clear. Here is the basic outline of converting a real time DOS program. I won't go
into the details because they a presented quite well in the examples provided with RT
Linux.
1. I am assuming that you have been using hardware interrupts to get 1ms periodic
rates for the real time portion of your task. All you have to do is put the real time
part of your dos code into an RT module. Creating an RT module is explained quite
clearly in the examples provided with RT Linux.
2. The foreground or non-real-time part of your program runs as a separate task in
Linux user space. You can send messages between the foreground task using fifo's or
shared memory.
Using fifo's assures that any messages, passed between the real time module and the
user space program, are never lost or missed.
One of the nice things about shared memory is that more than one foreground task can
access the information. In the past I have had up to three different user space tasks
accessing shared memory. The first displayed all of the pertinent data I wanted to
see. The second accepted commands and transmitted them to the real time task. And
the third logged data to disk. Having the three different tasks allowed me to change
some of the functionality of one task with stopping or interfering with the operation
of the others. However, the user space program may loose information that is rapidly
updated by the real time task.
I hope this helps.
Rich
> ----------
> From: [EMAIL PROTECTED][SMTP:[EMAIL PROTECTED]]
> Sent: Tuesday, January 26, 1999 3:57 AM
> To: [EMAIL PROTECTED]
> Subject: [rtl] [Q] About achieving 1 mks of execution period
>
>
> Hi.
>
> I'm trying to port an old DOS program to RT Linux, it emulates an more
> older processor which has an 1 MHz clock. What a hardware do I need to
> have an 1 mks RT task ? What a shortest time can I have on SMP
> system ? Anybody has such developing experience under RT Linux ?
>
> Thanks in advance. Any answers will be appreciated.
>
>
> --- [rtl] ---
> To unsubscribe:
> echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
> echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED]
> ----
> For more information on Real-Time Linux see:
> http://www.rtlinux.org/~rtlinux/
>
--- [rtl] ---
To unsubscribe:
echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED]
----
For more information on Real-Time Linux see:
http://www.rtlinux.org/~rtlinux/
