1. History of IT

2. Four basic periods: Premechanical era 1. Premechanical 2. Mechanical
3. Electromechanical
4. Electronic
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

3. 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

4. 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

6. 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)

8. 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

9. 1. 2. 3. 4.