s100 busses!

From: Dwight Elvey <elvey_at_hal.com>
Date: Wed May 10 11:18:07 2000

allisonp_at_world.std.com wrote:
> On Tue, 9 May 2000, Ron Hudson wrote:
>
> > Does anyone still sell s100 based computers?
> > Aren't they used still for process controll and automation?
>
> Effectively not for many years.
>
> > 2nd question
> > How did the control panel of the IMSAI work, was it controlled by a rom
> program
> > that lit the leds and read the switches?
>
> There was no rom in the base imsai. The frontpannel was all hardware and
> worked by inserting wait states in the instruction flow effectively
> stopping the micoprocessor at every cycle.

Hi
 This wasn't the only clever part. They also jammed instructions
into the 8080 to do fetches and stores. All they used were
a number of one shots, some glue logic and 3state buffers.
The first time I looked at how they did it, I was impressed.
I don't know if it was an original idea but it was clever.
Dwight
Received on Wed May 10 2000 - 11:18:07 BST