Transcript herman hollerith

Four basic periods:
1. Premechanical
2. Mechanical
3. Electromechanical
4. Electronic
1. Premechanical era
• around 3000 B.C. – 1450 A.D.
• inventions of:
- writing and alphabets
- pens and papers
- books and libraries
- numbering systems, first calculator
The Abacus
2. Mechanical age
• lasted from 1450 to 1850
• W. Shickard invented a computing machine (+, -)
• B. Pascal’s Pascaline (mechanical addition, subtraction of numbers)
• 1673 – Leibniz’s machine ( +, -, *, / )
• Ch. Babbage: - the difference engine
- the analytical engine (punch cards)
• J. M. Jacqard invented a loom that used the punch cards
The pascaline
Difference and analytic engines
3. Electromechanical age
• lasted from 1840 to 1940
• beginnings of telecommunication:
- telegraph (early 1800s), Morse code (1835, S. Morse),
telephone (1876, A. G. Bell), radio (1894, G. Marconi)
• Herman Hollerith: - census machine (punch cards)
- established the IBM
• MARK 1: -completed in 1942, an automatic-sequence calculator
- 3 calculations/sec, worked for 15 years
- 8 feet tall, 51 feet long, 2 feet thick, weighed 5 tons
4. Electronic age
• 1945 – ENIAC: - Electronic Numerical Integrator and Computer
- 1st fully electronic computer, used vacuum
tubes
- couldn’t store its programs
- developers: John Mauchly, J. Prosper Eckert
- funded by U.S. Army, used for military
purposes
• John von Neuman: binary system (0,1)
• stored-program computers: Manchester Mark 1, EDSAC, EDVAC
• the first general-purpose computer for commercial use:
UNIVAC (universal automatic computer)
Four generations of digital computing
1. - vacuum tubes=main logic elements
- used punch cards and rotating magnetic drums
2. - transistors as main logic element
- magnetic tape and discs instead of punched cards, magnetic
cores for internal storage of data
3. - intgrated circuits
- MOS memory replaced the magnetic cores
- development of operating systems and programming languages
4. – large-scale and very large-scale integrated circuits
- microprocessors, containing memory, logic, control circuits
(CPU=central processing unit)
- this allowed the home-use of PCs
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