by Sean Michael Ragan

In September of last year, Matt Mets blogged about Visual 6502, an in-browser simulation of the landmark MOS 6502 microprocessor, produced by San Francisco hacker Greg James and Montreal brothers Barry and Bryan Silverman.
Recently, the July/August issue of the American Institute for Archaeology’s Archaeology featured an interesting article about the story behind Visual 6502. It provides a concise overview of the 6502′s historical significance, and then goes on to cast the team’s reverse-engineering project in terms of “digital archaeology,” emphasizing the “excavation” metaphor: Like physical archaeologists, James and the brothers Silverman “dig” into the chip package, itself, to recover lost knowledge of our history.

Back in 1974, the original schematic for the 6502 was sketched out by hand on a drafting board. (In contrast, today’s design methodology has hundreds of engineers working on hundreds of computers creating archived digital files of their work when collaborating on today’s microprocessors.) The creator of the 6502’s schematic doesn’t know where that document is today, and very little information on how the chip was created survives. Further, in the more than 35 years since its design, the understanding of how this remarkable chip performed its functions was lost.