Z-Star EX

Has anyone successfully used an old Zenith Z-Star EX notebook computer as an
engine for a CNC G-Code interepreter? I've got one with 8 Mbytes of memory
running either DOS or Win 3.1. When running TurboCNC under pure DOS (from
the boot up, windows is not even in the pictur), I find that I can't get
reliable slewing beyond a few hundred steps per second. But, if I run the
same program using my Sony PCG-F430, I can get reliable (and repeatable)
slewing at about 4000 steps per second.

I got my 'scope out and looked at the step pulse. With the Sony, the step
pulse train was strong and showed no dither. With the Zenith, The pulse
train showed some dither (looks like a pulse dropped) which, I believe,
caused the motor to fail at anything but a low speed.

I tried removing the driver for the J-Mouse and also the external CD drive
that was attached, but these had no effect on the jerkiness. I'm thinking
that, somewhere, there's an interrupt being serviced that is eating into the
time which should be spent sending the pulse train out to the motors.

If anyone's had any luck with the Z-Star, I'd appreciate hearing what
software you're running and what tricks you had to do to make it work for
you.

Thanks,

-- Carol & Jerry Jankura
Strongsville, Ohio
So many toys, so little time....