Computer Studies / Data Processing · Lesson 1

Evolution, generations, types and characteristics of computers

JAMBWAECNECO

What the syllabus asks

JAMB: Section A Evolution of Computing (1 History of computing: pre-computing age to 19th century: abacus, slide rule, Napier’s bones, Pascal calculator, Leibniz multiplier, Jacquard loom, Babbage’s analytical engine, Hollerith census machine, Burroughs machine; 20th century: ENIAC, EDVAC, UNIVAC I, desktop PCs; 2 Classification by generation, size, purpose and type; modern systems: PC, desktop,…

WAEC: Computer evolution (computing devices I and II, contributions of founders); Fundamentals of computing (definition, characteristics, data and information)

NECO: Computer evolution (computing devices I and II, contributions of founders); Fundamentals of computing (definition, characteristics, data and information)

What you will learn

Define a computer and describe the input–process–output idea.
Describe the early computing devices and the contribution of each inventor.
Describe ENIAC, EDVAC, UNIVAC I and modern personal computers.
Relate each generation of computers to its technology, speed and storage.
Classify computers by type, size and purpose, with examples and uses.
Distinguish modern systems: desktop, laptop, tablet, smartphone, server, workstation, wearable.
State and explain the characteristics and limitations of computers.
Distinguish between data and information and state the qualities of good information.

Key points

A computer is an electronic, programmable device that accepts, processes, stores and outputs data (IPO/IPOS).
Two main constituents: hardware and software (plus humanware and data in some texts).
Abacus: beads on rods, place value. Napier’s bones (1617): multiplication by adding. Slide rule (Oughtred, c.1622): analog, logarithms.
Pascal (1642): gear-driven adding machine with carry. Leibniz (1673/1694): stepped drum; could multiply and divide.
Jacquard loom (1804): punched cards controlled patterns.
Babbage: Difference Engine and Analytical Engine (store, mill, cards); father of the computer. Lovelace: first program (1843).
Hollerith: punched-card tabulator for 1890 US census; company became IBM. Burroughs: printing adding machine (patents 1888).
ENIAC (1946): electronic, vacuum tubes, programmed by rewiring. EDVAC: stored program, binary (von Neumann, 1945). UNIVAC I (1951): first US commercial computer.
Generations: 1st vacuum tubes; 2nd transistors; 3rd ICs; 4th microprocessors; 5th AI and parallel processing.
Type: analog (measures), digital (counts), hybrid (both).
Size: super, mainframe, mini, micro (desktop, laptop, tablet, smartphone).
Purpose: general purpose (many jobs) and special purpose (one embedded job).
Characteristics: speed, accuracy, reliability, storage, automation, diligence, versatility; limitations: no own intelligence, GIGO, needs power.
Data are raw facts; information is processed, meaningful data.
Good information is accurate, timely, relevant, complete, clear and cost-effective.

Start here: What is a computer?

A computer is an electronic device that accepts data as input, processes it according to a set of stored instructions called a program, stores data and results, and produces output in the form of information. Two words in this definition matter most in examinations. Electronic means it works with electric signals rather than gears. Programmable means it can be given different sets of instructions, so the same machine can play music, calculate school fees or check a JAMB result.

The input–process–output cycle

Every computer job follows the same pattern. A cashier at a supermarket in Ikeja scans a tin of milk (input). The computer looks up the price and adds it to the bill (processing). It keeps a record of the sale (storage) and prints a receipt (output). Exam answers often call this the IPO cycle or, when storage is added, the IPOS cycle.

The two main constituents

A computer system has two main parts. Hardware is the physical parts you can touch: keyboard, monitor, system unit, printer. Software is the set of programs that tells the hardware what to do: Windows, Android, Microsoft Word. Hardware without software is like a car without a driver; software without hardware has nothing to run on. Some textbooks add a third part, humanware (the people who use and operate the computer), and a fourth, data.

Functional parts

Inside, a computer has an input unit, a central processing unit (CPU: control unit plus arithmetic and logic unit), a memory unit and an output unit. These are studied fully in cs2.

Worked example 1.1 (WAEC-style)

Define a computer and explain the steps by which an ATM converts a request into information. (6 marks)

Definition: an electronic, programmable machine that accepts data, processes it under stored instructions, stores it and outputs information.
Input: the customer inserts a card, types the PIN and the amount.
Processing: the computer checks the PIN and the balance with the bank’s system.
Storage: the transaction is recorded.
Output: cash is dispensed, a receipt is printed and the new balance shown.

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Practice questions

1. Which device used beads on rods for counting?

Abacus
Slide rule
Pascaline
Jacquard loom

Show answer

A: Abacus
The abacus is the oldest counting aid.

2. Napier’s bones were devised in

1642
1804
1890
1617

Show answer

D: 1617
John Napier published them in 1617.

3. Blaise Pascal built his adding machine in

1673
1834
1642
1617

Show answer

C: 1642
The Pascaline used geared wheels.

4. The Jacquard loom is important in computer history because it used

magnetic disks
punched cards to control patterns
vacuum tubes
transistors

Show answer

B: punched cards to control patterns
Babbage borrowed the punched-card idea.

5. Who is regarded as the first computer programmer for her notes on the Analytical Engine?

Ada Lovelace
Grace Hopper
Marie Curie
Florence Nightingale

Show answer

A: Ada Lovelace
Her 1843 notes contain an algorithm for the engine.

Key words

Computer: An electronic machine that accepts data, processes it under stored instructions, stores it and produces information.
Abacus: A frame with beads on rods used for counting and arithmetic; one of the oldest calculating aids.
Napier’s bones: Numbered rods devised by John Napier (1617) to multiply by adding partial products.
Slide rule: An analog calculating device with logarithmic scales, used for multiplication and division.
Pascaline: The adding machine built by Blaise Pascal in 1642, worked by geared wheels.
Stepped reckoner: Leibniz’s calculator using a stepped drum; it could add, subtract, multiply and divide.
Punched card: A card in which holes represent data or instructions; used by Jacquard, Babbage’s design and Hollerith.
Analytical Engine: Babbage’s design for a general-purpose mechanical computer with a store (memory) and a mill (processor).
Vacuum tube: A glass valve used as a switch in first-generation computers; bulky and hot.
Transistor: A small semiconductor switch (1947) that replaced vacuum tubes in second-generation computers.
Integrated circuit (IC): Many transistors on one small silicon chip; basis of third-generation computers.
Microprocessor: A complete CPU on one chip; basis of fourth-generation computers.

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