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Quest for a“Personal” Computer!

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Two forces at work

• Top-down- Time-sharing and interactivity

• Bottom-up- Personal calculators- Improvements in microchips

• When shall the twain meet?

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Reflect a bit...

• Intel 4004 and 8008- What applications were they originally

designed for?

http://en.wikipedia.org/wiki/Image:Datapoint2200img.jpg

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Reflect a bit...

• Intel's mentality- General-purpose microprocessors- Special-purpose software burned into ROM- Sell more chips! $$$

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Development Systems

• “Cross compiler”- A compiler that generates code for a

machine OTHER than the one it's running on!

- Write on a minicomputer, compile for a 8008!

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Development Systems

• Intellec-4 (1974)• Intellec-8 (1974)

- No need for cross compiling anymore!

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The Bitter Irony

• Intellec-4 and Intellec-8 were general purpose microcomputers!- Intel did not realize it- Not sold to the public

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The Bitter Irony

• Intellec-4 and Intellec-8 were general purpose microcomputers!- Intel did not realize it- Not sold to the public

WHY?

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About the same time...

• MICRAL (1973)• Intel 8008 processor

- $2,000- Not seen as “personal”

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More on MICRAL

• Invented by Thi T. Truong• Programmed by Philippe Kahn

- Founder of Borland!!

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Hobbyists

• Electronics Magazines- QST- Popular Electronics- Radio Electronics

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Hobbyists

• Electronics Magazines- Advertised “do it yourself” kits to build small

computers Kenbak-1 (1971) Scelbi-8H (1974) Mark-8 (1974)

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Altair 8800

• Popular Electronics (Jan 1975)

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Altair 8800

• Made by MITS- “Micro Instrumentation and Telemetry

Systems”• Forrest Mims and Ed Roberts

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Altair 8800

• Why was it “successful?”- Intel 8080 processor- Bus- Expansion slots

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Define “success”?

• MITS expected to sell hundreds• Received >1000 orders first month

- Backlog- Quality suffers

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Define “success”?

• Peripherals- Memory- Teletype- Keyboard/TV- Paper tape readers- Cassette tape I/O- Disk drives

• Most were not sold by MITS!

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Define “success”?

• Users groups• Magazines• Retail stores

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Altair's Legacy

• Not much by itself, but...• It was the “spark” that set off the home

computer revolution.- NOT the Intellec's- NOT the other hobbyist kits

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Gallery

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Gallery

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Gallery

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Gallery

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Demo

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“Test Question”

• On a scrap of paper, write a question that encapsulates one of the points from today's class, and turn it in.

• (Put your name on it!)