Juan Monroy — Media Technologies: Computers

Computers
- Hardware
  - Monitor
  - Motherboard
  - CPU
  - RAM
  - Expansion cards
  - Power supply
  - Optical disc drive
  - Hard disk drive
  - Keyboard
  - Mouse
- Input
- Software
  - instructions for the hardware
- Output
Mechanical Computers
- gears and levers
- adding machines, calculators, and machines
  - Stepped Reckoner (1672)
  - Difference Engine (1822)
- Jacquard Loom (1801)
- Analytical Engine (1837)
Analytical Engine
- Charles Babbage, 1837
- grind out calculations in a mill
- input/output: punch cards
- never completed
Bit
- Binary Digit
- logical values
  - yes/no
  - true/false
  - on/off
- only thing computers actually process
Byte
- combination of bits
- hexadecimal: 4-bits
- most text: 7–8 bits
Byte
- basic computer unit
- a letter of text
- example, American Standard Code for Information Interchange
Bits and Bytes
- 1-bit = 21 = 2 byte combinations
- 2-bit = 22 = 4 byte combinations
- 3-bit = 23 = 8 byte combinations
- 4-bit = 24 = 16 byte combinations
- 5-bit = 25 = 32 byte combinations
- 6-bit = 26 = 64 byte combinations
- 7-bit = 27 = 128 byte combinations
- 8-bit = 28 = 256 byte combinations
Like Morse Code
Storage
- storing bits
- record (write)
- retrieve (read)
Punch Card
- paper card
- sequential
- each hole represents a bit, e.g. “on”
- each “non-hole” represents a different bit, e.g. “off”
Magnetic Storage
- Each bit is “written” on a magnetically-charged metal particle
- read back and loaded to the computer
- non-volatile
  - magnetic tape
  - floppy disk
  - hard disk
- magnetic tape
- floppy disk
- first hard disk drive
  - IBM, 1956
  - size: a car
  - storage: 3.75 megabytes
  - cost: $30,000
- hard disk
  - size: about 2.5 – 3.5 inches
  - storage: 4 terabytes
  - cost: $150
  - disk spins between 5400 and 7200 rpm
  - magnetic head is about 10 nm from disk surface
- Optical Storage
  - binary data store on a metal disk
  - encased in plastic
  - read/written by laser light or electromagnetic waves
  - CD: Compact Disks (red laser)
  - DVD: Digital Versatile Disk (white laser)
  - Blu-ray (blue laser)
- Processors
  - process and calculate numbers
    - one bit at a time
  - faster than human counting
    - and more accurate
  - faster than mechanical computers
Diodes
- vacuum tubes
- Thomas Edison’s lightbulb, 1883
- John’s Fleming valve, 1904
- Lee deForest’s audion,
ENIAC
- first electronic computer, 1946
- “Giant Brain”
- Electronic Numerical Integrator And Calculator
- processed calculations for the hydrogen bomb
Colossus
- British, 1943–1945
- World War II
- crack Nazi codes
  - Lorenz cipher
  - non-Morse code transmissions
Big Computers for Big Guys
- governments
- military
- university research
- World War II: to save the world
“Personal” Computer, 1954
Transistor
- Bell Labs, 1947
- semiconductor
- telephone circuits
- transistor radios
- electronic computers
Minicomputers
- powered by transistors
- mid 1960s
- smaller than “mainframe” computers
- cabinet-sized
- cost about $25,000
Minicomputers for Corporations
- banking records
- university enrollments
- airline reservations
- hotel bookings
Microprocessors
- Intel, 1971
- silicon switches
- Moore’s law
  - every two years…
  - double the number of transistors…
  - in the same circuit.
Microcomputers
- powered by microprocessors
- emerged 1970s
- small central processing unit (CPU)
- desktop and tabletop sized
Personal Computer
- microcomputers powered by microprocessors
- emerged in 1970s and 1980s
- desktop sized
- keyboard, display, magnetic storage
Altair 8800
- microcomputer kit, 1975
- Intel 8800 microprocessor
- 256 bytes of RAM, no storage
- front panel with lights
- mail order, $400–$500
- first personal computer
Apple I
- Steve Jobs and Steve Wozniak, 1976
- demonstrated at Homebrew Computer Club
- fully assembled circuit board
  - keyboard
  - TV set
- sold for $666.66
Xerox Alto
- Xerox Palo Alto Research Center, 1973
- GUI: graphical user interface
- desktop metaphor
- tens of thousands dollars
- sparked the GUI computer of the 1980s
Macintosh
- Apple, 1984
- desktop metaphor
- graphical user interface
- 128 kilobytes of RAM
- no storage
IBM PC Jr
- 1981
Handhelds
- smartphones
- tablets
Wearables
- smart watches
- shirt
- glasses
- wristwatch
- wristbands
- trousers
- hand
- shoes
Digital Media
- modern Media: daguerrotype
- computable data: analytical engine