Oral History of William David "Bill" Mensch Jr.

Bill Mensch shares his life story, from his early career at Motorola to co-designing the legendary 6502 microprocessor and founding WDC.

Interviewed by Stephen Diamond, on November 10, 2014 in Mountain View, California, X7273.2015 © Computer History Museum Bill grew up on a farm north of Philadelphia. He found his way to Temple University where he studied electrical engineering, but did not complete a degree. After working at a few low-paying jobs for small companies, he found his way to Arizona where he attended the University of Arizona. After a time at Philco Ford, he got a job at Motorola that he saw as an industry leader. When he began work, he was enrolled in a one-year training program that involved rotating among four different areas of the company. Bill eventually joined the microprocessor design group. While there he designed a PIA (Peripheral Interface Adapter), I/O buffers, clock generators, etc. When Motorola asked him to transfer to Texas, he decided to join his colleague, Chuck Peddle, and join MOS Technology in Pennsylvania where they could design their own microprocessor. They took a half dozen other Motorola people with them and set out to design a microprocessor, the 6502, which would out perform Motorola’s 6800. The 6502 turned out to be a spectacular success. One of their prime goals was to design a product that could be sold profitably for 10% of the cost of other microprocessors of that day. They felt that they could open up many new markets with a product that cheap. In that they were very successful. It became the standard processor chip for Apple, Atari, and even the BBC Micro in England. Bill Mensch eventually found his way back to Arizona, where he started the “Western Design Center.” WDC developed a CMOS version of the 6502 and the company continues to be active in the microprocessor market. * Note: Transcripts represent what was said in the interview. However, to enhance meaning or add clarification, interviewees have the opportunity to modify this text afterward. This may result in discrepancies between the transcript and the video. Please refer to the transcript for further information - computerhistory.org/collections/catalog/102739969 Visit computerhistory.org/collections/oralhistories/ for more information about the Computer History Museum's Oral History Collection. Lot Number: X7273.2015 Catalog Number: 102739969