Thunderscan: A clever device transforms a printer into a scanner

Summary

The first project that I worked on for Apple after starting in August 1979 was writing low level software for the Silentype printer (see What Hath Woz Wrought), a cute, inexpensive thermal printer for the Apple II, that was based on technology licensed from a local company named Trendcom. In typical Apple fashion, we improved on Trendcom's design by replacing their relatively expensive controller board with a much simpler one that relied on the microprocessor in the Apple II to do most of the dirty work. The only other engineer working on the project was Victor Bull, who was the hardware designer and also the project leader. Vic was smart, taciturn and easy to work with, and I learned a lot from him about how thermal printers worked, as well as how things worked at Apple. We finished the project quickly, and the Silentype shipped in November 1979, less than four months after I began working on it. In May 1984, during my leave of absence from Apple (see Leave Of Absence), I received a phone call from Victor Bull, who I hadn't heard from in a couple of years. He had left Apple more than a year ago to work with his friend Tom Petrie at a tiny company based in Orinda named Thunderware, that sold a single product called Thunderclock, an inexpensive calendar/clock card for the Apple II. Victor said that he thought that I might be interested in writing software for an exciting, clever new product that Thunderware was developing for the Macintosh, which he refused to describe over the phone. He invited me to come visit them to check it out. In early June, I drove up to Thunderware's office in Orinda, which was about an hour's drive from my house in Palo Alto. After I arrived at their modest headquarters, Vic introduced me to his partner, Tom Petrie, and I signed a non-disclosure agreement before they ushered me into a back room to see their demo. The most popular printer for both the Apple II and the Macintosh was the ImageWriter, a $500 dot-matrix printer capable of render...