View Full Version : The Slow-Stepping Debugger

June 23rd, 2008, 11:59 PM

I just got some old computer magazines from 1977 called "Kilobaud", "the small computer magazine". I don't have the first issue but I've heard that it had an article titled "You have an IMSAI - so now what?"

Issue number four has the article named in the subject of this post. It says that the IMSAI has in it's front panel the components for a single step through memory function (like the Altair 8800B) and that adding a ten microfarad capacitor will change it to an automatic slow step through memory circuit.

The whole idea of this is to allow the programmer to slowly run his program to see where it crashes. I believe that the interval is 1.5 seconds, which seems a little fast until you realize that all you have to do is remember the last address that the program was still functioning normally to find the bug.

I had had the idea of slowing my Science Fair Microcomputer Trainer down by adding a bigger capacitor to the clock circuit (400 KHz). So it was interesting to see that others had had the same idea.

My University library still has these magazines, and the public is welcome to look at them. They also have copy machines available. Perhaps a trip to your library will give you a chance to see how they did it in the old days.