IP Calculator Final Version

[Alex Tweedly]

On 27/01/2015 23:53, Ralph DiMola wrote:
> I wrote the OS for a custom computer for solving the 3d solution of the
> FA-18 Flight Simulator back in the 80's. I had to write the floating point
> input/display routines. I was very proud how I anticipated all the combos
> for FP input. 1.0/1/1e10/.0005 e-20/0.0005/-55/1.125 e0 and all the other(so
> I thought) input expectations and error handling. I Demoed it for colleague
> before I presented it to the team and he typed +0 and it crashed the OS.
> Woops......
>

Back in the 80's, I worked on a graphics display/editor for an IC design 
system; it worked on Tektronix 401x displays.

We had a really irritating bug that we just couldn't find, so every so 
often, during a screen refresh (which could take 10-30 seconds), the 
program would crash; this was always preceded by failures in the 
re-drawing, which could be easily recognized by someone experienced with 
it, but weren't immediately obvious to a casual observer.

The Tektronix displays had this really stooopid design feature - the 
on/off switch was on the lower right front of the pedestal just where 
your right foot could inadvertantly catch on it as you crossed or 
uncrossed your legs, and switch off the display.

It was surprising how often the operator demo-ing the system to a 
potential customer would accidentally hit that switch when failure mode 
was imminent :-)

-- Alex.