Chapter 2: the computer
input: type, point, click, devices
output: screen, display, digital paper, (files, emails)
virtual reality and 3D visualizations
physical devices
sound, smell, haptic, sensors
paper output (turn around, thru put)
printers, scanners, OCR
memory
	RAM
	disks
	capacity
	access methods
processing
	too slow, too fast, processing limits
	networks
interaction: 
	info transfer human to computer and back

computer system
	keyboard, mouse, screen, tower
	HCI emerged as batch became interaction
	how many computers do you have?

	Text
		keyboard (QWERTY, DVORAK, chord, ergonomic)
		keypads: calculator vs telephone; digital entry of letters
		handwriting (stroke)
		gesture
	speech
		telephone, access, hands occupied, RSI
	position point draw
		mouse (1964), footmouse
		touchpad
		trackball (upside down mouse)
		thumbwheel
		joystick
		touch sensitive
		stylus, lightpen
		touching can be tiring, obscure, grease
		digitizing tablet
		eyegaze
		cursor

	display
		specialized can have no screen
			remote control
		pixel: black and white biitmap
		often 32 bits for pixel
		total number 4:3; 1024x768, 1600x1200
		density (per inch) 72-96
		computer may have less resolution than screen—stretch
		angles and curves hard to do (anti-aliasing)
		brain compensates for blurs	
		
		CRT rgb; cheap, radiation, eyestrain
		LCD less power, flat, less eyestrain
			notebook and laptop
		large and situated displays
			HDTV 16:9
			can join multiple screens in a wall
			can project
				back projection
		digital paper
	virtual reality and 3D
		from 2 degrees of freedom to 6
		cockpit
		3D mouse (roll pitch yaw)
			position, up/down, left/right, twist
			hard to hold in air long time
		data glove
		helmets (goggles)
		whole body tracking
		stereoptian—old tech
			polarized
			timed
			red-green glasses
			narrow viewing angles
			motion sickness
			simulators
	physical controls
		flashing 
		heads up display
		sound
			click/tone on key press
		touch, feel, smell
			haptic; force, resisence, texture
		controls can be very different!
		Bio-sensing (hands under faucet)

	paper printing scanning
		will we ever ge a paperless office?
		Computers make it easier to pringt, reprint, revise
		dot matrix. Ink jet, bubble jet, laser
		fonts
			size, style, drawings, clip art, 
			page description language
			(post script)
			pt 1/72 inch ; 12 pt has 6 lines per inch
			proportional font; fixed pitch
		screen and page
			WYSIWYG
			screen width may not match paper width
		scanners OCR
			flat vs hand held
			document storage
			
	memory (STM LTM)
		RAM volatile	
		flash
		disks
		CD ROM (WORM) EPROM
		speed vs capacity	
		bottleneck between disk and memory
		speed capacity expense		
		compression
			huffman
			difference
		ASCII
		access
			index
			extra indecices add cost
			how do spell checkers work
		networks
		speed
			too slow
			too fast
		computation bound
		storage bound
		graphics bound