Archaeology Magazine - July/August 2011 - 32
David X. Cohen has said that his fondness for the chip came from programming video games on his Apple II Plus in high school. According to Mensch, through the mid-1980s, beginning computer engineers learned the craft of microprocessor design by studying the 6502. Today, while chip designers may appreciate the simplicity of the 6502, they design only discrete parts of the CPUs. The era of the tall, thin man is over, says Mensch. n , while browsing a retro computer parts website, Greg James saw two 6502s on sale for $10 each. He bought them both. He’d recently cleaned out his garage and stumbled upon A 1974 photo of the MOS Technology 6502 design team with a design schematic. Bill Mensch is standing second from the left. an Atari 2600 and an Apple II, two machines that had “played a big part in my childhood.” He credits the former with teaching him that computers were fun and dreds of pages with different sections of a chip on each. His the latter with introducing him to programming. When he method, he says, guaranteed that the logic flow (specifically, realized that both ran on essentially the same chip—the how steps of process control and arithmetic are performed Atari contains an MOS Technology 6507, a 6502 in differby the chip and then passed along) matched with the wiring ent plastic packaging—he started to research the microproof different transistors and circuits on the microprocessor. It’s cessor, eventually tracking down an incomplete schematic a “what you see is what you get” approach that means, despite that he thought he could improve on to determine how the the original diagram being lost, the excavation of the chip by chip worked. the Visual 6502 team would be able to clearly demonstrate To analyze and then preserve the 6502, James treated it how it functioned. “If anybody really studies Visual 6502 in like the site of an excavation. First, he needed to expose the detail,” Mensch explains,“what they’ll find is that everything actual chip by removing its packaging of essentially “billiardwas strategically located at its best position on the chip.” ball plastic.” He eroded the casing by squirting it with very When it debuted at the Western Electronic Show and hot, concentrated sulfuric acid. After cleaning the chip with Convention at San Francisco’s St. Francis Hotel, MOS Techan ultrasonic cleaner—much like what’s used for dentures nology’s 6502 was four times faster and two to four times or contact lenses—he could see its top layer. smaller than competing chips offered by Motorola and Intel. The 6502 has three basic layers. The bottom layer is a It was also roughly a tenth of the cost, being sold for $25 a wafer of silicon known as the “substrate.” Above it is a thin piece out of “a big old Mason jar.” layer of polysilicon wires that form transistors and build Soon, the 6502 would become ubiquitous. Apple Comcircuits around the chip. The top layer is thick metal wiring puter cofounder Stephen Wozniak was among those who primarily for supplying power. Its bulky structures obscure picked up a couple of chips. “I would credit Apple and the polysilicon’s complex maze of wiring. Wires in a single Wozniak for popularizing the 6502,” says Mensch, adding layer can’t cross over one another, so connections can be made that personal computing took off thanks to the Apple II’s between layers to clear the cobweb of polysilicon and pack expansion slots that allowed consumers to add memory or circuits closer together. install an extra floppy disk drive. Though Apple was among After photographing the chip’s topmost layer, James the first to incorporate the 6502, it wasn’t the best-selling removed the metal using phosphoric acid mixed with acetic brand to use the chip. In the mid-1980s, casual computer acid and nitric acid heated to 120 degrees Fahrenheit. Once consumers favored the Commodore family of home comthe metal was gone, he took another photograph. “That was puters, which also ran on a version of the 6502. But the the money photograph,” says James of the moment when, Nintendo Entertainment System outsold every other device in a real-world excavation, archaeologists can observe a that the 6502 appeared in, combined, moving close to 62 landscape of artifacts, like canals or foundations of homes. million units. James went one step further, removing the polysilicon layer The 6502’s profile extended to pop culture, where it with hydrofluoric acid, so that he could capture an image of apparently powered two well-known fictional robots: the bare substrate. the Terminator and Bender from the animated series Once he had all three photographs, he enlarged them to Futurama. In the 1984 film The Terminator, scenes shown thousands of times their actual size and aligned them, creatfrom the perspective of the title character, played by Arnold ing images of a complicated network akin to a dense map of Schwarzenegger, include 6502 programming code on the left roadways. He then traced them, creating a complex network side of the screen. In a 1999 episode of Futurama, it’s revealed of lines like the maps drawn by Google or Mapquest. The that Bender’s brain is powered by a 6502. Executive producer
32 ARCHAEOLOGY • July/August 2011
I
Archaeology Magazine - July/August 2011
Table of Contents for the Digital Edition of Archaeology Magazine - July/August 2011
Archaeology Magazine - July/August 2011
Table of Contents
Editor’s Letter
From the President
Letters
From the Trenches
Reviews
World Roundup
Rebuilding Beirut
Digging Into Technology’s Past
The Nok of Nigeria
Assisi’s Roman Villa
Australia’s Shackled Pioneers
Letter from Pittsburgh
Artifact
Archaeology Magazine - July/August 2011 - Archaeology Magazine - July/August 2011
Archaeology Magazine - July/August 2011 - Cover2
Archaeology Magazine - July/August 2011 - 1
Archaeology Magazine - July/August 2011 - Table of Contents
Archaeology Magazine - July/August 2011 - 3
Archaeology Magazine - July/August 2011 - 4
Archaeology Magazine - July/August 2011 - 5
Archaeology Magazine - July/August 2011 - Editor’s Letter
Archaeology Magazine - July/August 2011 - 7
Archaeology Magazine - July/August 2011 - From the President
Archaeology Magazine - July/August 2011 - 9
Archaeology Magazine - July/August 2011 - Letters
Archaeology Magazine - July/August 2011 - From the Trenches
Archaeology Magazine - July/August 2011 - 12
Archaeology Magazine - July/August 2011 - 13
Archaeology Magazine - July/August 2011 - 14
Archaeology Magazine - July/August 2011 - 15
Archaeology Magazine - July/August 2011 - 16
Archaeology Magazine - July/August 2011 - 17
Archaeology Magazine - July/August 2011 - 18
Archaeology Magazine - July/August 2011 - 19
Archaeology Magazine - July/August 2011 - Reviews
Archaeology Magazine - July/August 2011 - 21
Archaeology Magazine - July/August 2011 - World Roundup
Archaeology Magazine - July/August 2011 - 23
Archaeology Magazine - July/August 2011 - Rebuilding Beirut
Archaeology Magazine - July/August 2011 - 25
Archaeology Magazine - July/August 2011 - 26
Archaeology Magazine - July/August 2011 - 27
Archaeology Magazine - July/August 2011 - 28
Archaeology Magazine - July/August 2011 - 29
Archaeology Magazine - July/August 2011 - Digging Into Technology’s Past
Archaeology Magazine - July/August 2011 - 31
Archaeology Magazine - July/August 2011 - 32
Archaeology Magazine - July/August 2011 - 33
Archaeology Magazine - July/August 2011 - The Nok of Nigeria
Archaeology Magazine - July/August 2011 - 35
Archaeology Magazine - July/August 2011 - 36
Archaeology Magazine - July/August 2011 - 37
Archaeology Magazine - July/August 2011 - 38
Archaeology Magazine - July/August 2011 - Assisi’s Roman Villa
Archaeology Magazine - July/August 2011 - 40
Archaeology Magazine - July/August 2011 - 41
Archaeology Magazine - July/August 2011 - 42
Archaeology Magazine - July/August 2011 - 43
Archaeology Magazine - July/August 2011 - Australia’s Shackled Pioneers
Archaeology Magazine - July/August 2011 - 45
Archaeology Magazine - July/August 2011 - 46
Archaeology Magazine - July/August 2011 - 47
Archaeology Magazine - July/August 2011 - 48
Archaeology Magazine - July/August 2011 - 49
Archaeology Magazine - July/August 2011 - 50
Archaeology Magazine - July/August 2011 - 51
Archaeology Magazine - July/August 2011 - 52
Archaeology Magazine - July/August 2011 - Letter from Pittsburgh
Archaeology Magazine - July/August 2011 - 54
Archaeology Magazine - July/August 2011 - 55
Archaeology Magazine - July/August 2011 - 56
Archaeology Magazine - July/August 2011 - 57
Archaeology Magazine - July/August 2011 - 58
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Archaeology Magazine - July/August 2011 - 67
Archaeology Magazine - July/August 2011 - Artifact
Archaeology Magazine - July/August 2011 - Cover3
Archaeology Magazine - July/August 2011 - Cover4
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