I published Bugbook III in August 1975, which was one year after I wrote my August-1974, Bugbooks I and II. As was the case for Bugbooks I and II, breadboarding auxiliary functions (four logic switches, four logic indicators, two pulsers, one clock, and one seven-segment display) were based upon “LR Outboards”***.
Although the 1975 E&L Instruments’ MD-1** microcomputer trainer and the 1974, auxiliary-function hardware*** are not available in 2017, it should be possible to dry lab the experiments in Bugbook III. In fact, the dry-lab approach was responsible for the majority of the sales of Bugbook III. For example, during 1975-77, only about 1700 MD-1** microcomputer trainers (sales price about $1500) were sold, whereas several hundred thousand typewritten Bugbooks III (or its typeset equivalent) were sold.
Despite its modest sales, the MD-1** microcomputer trainer was a significant innovation in the United States. Why? Because it married a solderless breadboard with the address, data, and control buses of the 40-pin, 8080- microprocessor integrated circuit. Dr. Titus was a genius as a microcomputer-trainer designer. It should be no surprise that Bugbook III became an educational innovation because it was the first professional-level laboratory book that explained how and why a microprocessor worked. Blacksburg, VA and Virginia Polytechnic Institute & State University -- despite being located in rural Virginia – played an important educational role in the microprocessors revolution during the 1970s.
Bugbook III was organized as a series of eight chapters:
1. What is a microcomputer?
2. Breadboarding with the MD-1** microcomputer
3. An introduction to microcomputer programming
4. Generating a device select pulse
5. Clock cycles and timing loops
6. Generating status information
7. Microcomputer input/output
8. Subroutines, interrupts, external flags, and stacks
Dr. Jonathan Titus, designer of the MD-1** microcomputer trainer, wrote Chapter 8, which was the only chapter in the entire Bugbook series that was written by somebody other than myself.
Definitions of more than fifty jargon terms were provided in Bugbook III.
For each experiment in Bugbook III, I used a Leroy Lettering set to create a coherent set of schematic diagrams. Breadboarded experiments – using the MD-1** microcomputer trainer -- were created directly from the schematic diagrams. Bugbook III was written using an IBM Selectric typewriter and several different Selectric typeballs (see https://en.wikipedia.org/wiki/IBM_Selectric_typewriter ). Bugbooks I, II, III, V, and VI were printed at Southern Printing (Blacksburg VA) directly from my typewritten pages.
Can you imagine the joy that I felt by being able to understand – by the marriage of a solderless breadboard to an 8080 microprocessor chip -- how any computer worked?
** The original “Mark 80” microcomputer was retitled as the MD-1 microcomputer.
*** Created by David Larsen in the department of chemistry at VPI&SU.