The document discusses the history of computing devices. It describes seven early calculating devices: the abacus, Napier's bones, the slide rule, Pascal's calculator, Leibniz's calculator, Babbage's analytical engine, and Hollerith's punched-card machine. It then groups computing devices into three categories: manual-mechanical devices powered by hand like the abacus and slide rule; electromechanical devices powered by electric motors like calculators and punched cards; and electronic devices using circuits, transistors, and chips like modern computers.

1. Lesson 3

2. 3‐1 The History of Computers
3‐2 The Earliest Computing Devices
1. Abacus
2. Napier’s Bones
3. Oughtred’s slide rule
4. Pascal’s Calculator
5. Leibnir’s Calculator
6. Babbage’s analytical Engine
7. Hollerith’s Punched‐card Machine

3.  Historical records will tell us that man has
invented three types of devices to assist him
in calculating and processing data. They are:
 Manual mechanical
 Eletromechanical
 Electronic

4.  Manual‐mechanical : A simple mechanism
powered by hand
 Abacus
 Slide rule
 Electromechanical: It is usually powered by an
electric motor and uses switches and relays.
 Household electrical appliances
 Calculators
 Punched cards

5.  Electronic : a device which has its principal
components circuit boards, transistors or
silicon chips and the like
 Modern digital computer

6. 3‐2 The Earliest
Computing Devices
1. Abacus

7. 3‐2 The Earliest
Computing Devices
2. Napier’s
Bones

8. 3‐2 The Earliest
Computing Devices
3.
Oughtred’s
Slide Rule

9. 3‐2 The Earliest
Computing Devices
4. Pascal’s
Calculator

10. 3‐2 The Earliest
Computing Devices
5. Leibniz’s
Calculator

11. 3‐2 The Earliest
Computing
Devices
6.
Babbage’s
Analytical
Calculator

12. 3‐2 The Earliest
Computing
Devices
7.Hollerith’s
Punched‐
card
Machine