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Fortran Assignment

• Questions?

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Computer Science

• Origins in 1950s- LGP-30 and IBM 650

• 1964- 12 universities w/ CS

• 1968- 100 universities w/ CS

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Computer Science

• What is it?- Use of computers for university

administrative work?

- Study of computer hardware?

- Study of algorithms?

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Computer Science

• ACM “Curriculum '68”- Math, theory, algorithms

- Why is this ironic?

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Also in 1968

• “Art of Computer Programming” by Donald Knuth- Emphasis on algorithms

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Also in 1968

• Structured programming- “GOTO considered harmful”

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Also in 1968

• TRAC programming language- Copyrighted software!!!

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Also in 1968

• Conference on “Software Engineering”- Sponsored by NATO

- Called for more discipline in programming

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Also in 1968

• IBM “unbundles” its software- Originally, hardware and software were sold

together

- Software is now buyable and sellable

- Room for competition!

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Evolution of Software

• Not foreseen by computer pioneers• Industry slowly realizes:

- Software exists

- Software is important

- It's worth building tools to support it

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Mainframe Era

• Never left idle!• Not interactive

- programmers did not use the machine directly

• Data available as printouts

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However...

• Not all problems are suited for batch processing.

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However...

• Not all problems are suited for batch processing.- Examples from book:

Insurance company IRS NASA

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NASA

• Sputnik 1957 started “space race”• Unlimited budget for space exploration

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NASA

• Greenbelt, Maryland (1961)- Hacked a IBM 7090 to operate in real-time- Input data from radar stations in Florida- “Mercury Monitor” system

early “interrupt-driven” software

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NASA

• Mainframes aren't supposed to work that way!

• Modifications were expensive, but they worked!- Paved the way for future real-time computing

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Earlier interactive machines

• Review:- LGP-30- Whirlwind- SAGE

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How?

• How can a computer be both interactive and inexpensive?- Use transistors from the start- Use short word length- Direct memory access (DMA)

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THE RESULT:

• The “minicomputer”- Entirely new class of machine- Opened computing to new markets

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Ken Olsen

• Student at MIT (1950s)- Worked on Whirlwind, TX-0

• Founded Digital Equipment Corporation (DEC)

• The “minicomputer company”

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PDP-1

• “Programmed Data Processor 1”- Inspired by TX-0

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PDP-1

• 1960• 100,000 additions per second• 4000 18-bit words

- (9 Kilobytes of memory)

• $120,000 (50 sold)

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PDP-1

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PDP-1

• Spacewar!- “First” video game- Made at MIT (1962)

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Marketing

• IBM- lease- supply system software

• DEC- sell- let users customize machine

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PDP-8

• 1965• 12-bit word length• 35,000 additions per second• 6 Kbytes of memory

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PDP-8

• 8 cubic feet• 250 pounds

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PDP-8

• 8 cubic feet• 250 pounds• $18,000

- crazy!

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PDP-8 Input/Output

• Teletype ASR-33- cheaper and more

durable than the Flexowriter!

- ASCII-based- (see page 134)

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Value-Added Resellers

• DEC machines were not easy to program (at first)

• Basis for 3rd-party products- picture on page 136

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DEC's legacy

• Minicomputers:- Brought interactive computing to a wide

audience- Direct ancestor of the personal computer

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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!)