Re: I made a Success of it!

Ian et al,

Regarding setting up Linux/RT Linux and shared memory on a 486 with 64
MB of RAM (64 MB, correct?), note that there is a pitfall with 486s and
shared memory: you can only allocate up to, BUT NOT INCLUDING, 1 MB of
shared memory. Fortunately the EMC data structure only occupies about
500K so this is not a problem. Set aside 768K so the numbers are easier,
which means bumping up the set-aside by 256K = 0x40000.

To set up LILO for this, you need make the /etc/lilo.conf append line be
this:

...
append="mem=0x3F40000"

Note that you can use the "0x" notation instead of the "m" or "M"
notation.

Next, change the emc.run (or whatever you call you run script) to pass
this to the motion controller via insmod, e.g.,

...
# install motion module in kernel
echo "installing motion module..."
insmod -f plat/rtlinux_09J/lib/steppermod.o SHMEM_BASE_ADDRESS=0x3F40000
PARPORT_IO_ADDRESS=0x378
...

And finally, make the corresponding change in the INI file, e.g.,

...
[EMCMOT]
...
SHMEM_BASE_ADDRESS = 0x3F40000
...

This 3-part harmony sets aside the shared memory at boot time, tells the
motion controller what it is, and tells the task level controller what
it is. Note that the motion controller can't read INI files so we have
to live with passing it as a symbol=value argument to insmod.

Forgive me if you tried something like this during one of your nine
attempts.

--Fred