Four basic periods 1 Premechanical 2 Mechanical 3

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 1800 s), 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 - 1 st 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

1. 2. 3. 4.