HCI-631: Software Architectures for User Interface

Scott Hudsonhudson@cs.cmu.edu

Office: NSH 3523Office Hours: Tues 3:00-4:00

(and by appointment)

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What is this class about?

Organizing principles of UI software

Practice in UI implementation

(About HCI-630…)

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Why is this interesting?

Computers are exploding into society– Pervasive computing power– Small, cheap, powerful

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World’s smallest web-server (runs Linux)

http://wearables.stanford.edu/hardware.html

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That only lasted 3 months…

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That only lasted 3 months…

http://www-ccs.cs.umass.edu/~shri/iPic.html

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Parts cost is around $1

If you can add $3-$5 to the cost of something, you can add a processor– if there is something of value to be

gained (doesn’t have to be much)

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Parts cost is around $1

~80x faster than the computer that “landed men on the moon”<50Khz (0.05Mhz) vs. 4Mhz

And ~2x memory~2K RAM, ~64K ROM vs.

41b RAM, 259K EEPROM

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We haven’t seen anything yet

Pop quiz: what is this

Good S

tuff

Time

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Moore’s Law

Good S

tuff

Time

You are here

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Moore’s law

At given price point, CPU speed doubles every 18 months– Low end (<$1) chip will have today’s

high-end performance in ~10 years Corollary: at a given

performance point price drops fast

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Hard to really understand exponential growth There has been huge

performance gains since (say) 1965

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Hard to really understand exponential growth There has been huge

performance gains since (say) 1965

EVERY SINGLE BIT of those speed gains will happen again in 18 months!!

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Thought experimentFrom Douglas Engelbart (invented mouse & hypertext)

Suppose you and everything you could see suddenly got exactly 10 times bigger.

Could you tell the difference?

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Thought experimentFrom Douglas Engelbart (invented mouse & hypertext)

Mass scales by volume, but strength of your chair scales by cross-sectional area– Chair collapses under 10x weight ratio– Not so important because many of your

bones will break for the same reason– Not really an issue because oxygen

consumption scales by volume, but lungs’ ability to absorb it scales by area

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Thought experimentFrom Douglas Engelbart (invented mouse & hypertext)

Moral of the story: Large (order of magnitude) changes

can have a huge impact

Good S

tuff

Time

You are

here

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Thought experimentFrom Douglas Engelbart (invented mouse & hypertext)

Moral of the story: Large (order of magnitude) changes

can have a huge impact

All hell is about to break loose!

Cool! But only if its usable!

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End result: big impact on the world

Large numbers use computers– Report: 50% of Americans now have

internet access No one in our society is not

affected in some way by computers

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Massive computational power available for next to nothing No longer “Can you build it?” Now: “Can they use it?”

(“Will they use it” => “Can I sell it”)

This class is to teach fundamentals of building (usable) interactive systems

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Syllabus

Me Text Projects Grading (55% proj, 45% exams)

– Midterm and comprehensive final

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Syllabus

On-line materials:http://www.cs.cmu.edu/~hudson/

teaching/05-631

(any second now…)

Schedule– Don’t take this TOO seriously

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