computer
computer is an electronic programmable machine.it respond to a specific type of instruction or execute this instruction(program)
History of computer science
Abacus 3000 BC
beads on rods to count and calculate still widely used in Asia
way back when side Rule
Slide Rule 1630 based on Napier’s rules for logarithms used until 1970s
19th century
jacquard loom -1801
first stored program - metal cards first computer manufacturing still in use today!
Charles Babbage - 1792-1871
Difference Engine c.1822 huge calculator, never finished Analytical Engine 1833 could store numbers calculating “mill” used punched metal cards for instructions powered by steam! accurate to six decimal places
Analytical Engine
Vacuum Tubes - 1941 - 1956
First Generation Electronic Computers used Vacuum Tubes Vacuum tubes are glass tubes with circuits inside. Vacuum tubes have no air inside of them, which protects the circuitry.
UNIVAC - 1951
first fully electronic digital computer built in the U.S. Created at the University of Pennsylvania ENIAC weighed 30 tons contained 18,000 vacuum tubes Cost a paltry $487,000
Grace Hopper
Programmed UNIVAC Recipient of Computer Science’s first “Man of the Year Award”
First Computer Bug - 1945
Relay switches part of computers Grace Hopper found a moth stuck in a relay responsible for a malfunction Called it “debugging” a computer
First Transistor
Uses Silicon developed in 1948 won a Nobel prize on-off switch Second Generation Computers used Transistors, starting in 1956
Second Generation – 1965-1963
1956 – Computers began to incorporate Transistors Replaced vacuum tubes with Transistors
Integrated Circuits
Third Generation Computers used Integrated Circuits (chips). Integrated Circuits are transistors, resistors, and capacitors integrated together into a single “chip”
Operating System
Software – Instructions for Computer Operating system is set of instructions loaded each time a computer is started Program is instructions loaded when needed
Third Generation – 1964-1971
1964-1971 Integrated Circuit Operating System Getting smaller, cheaper
The First Microprocessor 1971
Intel 4004 Microprocessor
The 4004 had 2,250 transistors four-bit chunks (four 1’s or 0’s) 108Khz Called “Microchip”
What is a Microchip?
Very Large Scale Integrated Circuit (VLSIC) Transistors, resistors, and capacitors 4004 had 2,250 transistors Pentium IV has 42 MILLION transistors Each transistor 0.13 microns (10-6 meters
4th Generation – 1971-present
MICROCHIPS! Getting smaller and smaller, but we are still using microchip technology
Birth of Personal Computers - 1975
MITS Altair
256 byte memory (not Kilobytes or Megabytes) 2 MHz Intel 8080 chips Just a box with flashing lights cost $395 kit, $495 assembled.
Generations of Electronic Computers
Evolution of Electronics
Evolution of Electronics
Vacuum Tube – a dinosaur without a modern lineage Transistor , Integrated Circuit, Microchip
IBM PC - 1981
IBM-Intel-Microsoft joint venture First wide-selling personal computer used in business 8088 Microchip - 29,000 transistors 4.77 Mhz processing speed 256 K RAM (Random Access Memory) standard One or two floppy disk drives
Apple Computers
Founded 1977 Apple II released 1977 widely used in schools Macintosh (left) released in 1984, Motorola 68000 Microchip processor first commercial computer with graphical user interface (GUI) and pointing device (mouse)
