Computer Basics and Generations

What to remember

• A computer is an electronic machine that takes input, processes it, stores it and gives output. The cycle is: input, process, output, storage.
• Five generations are linked to the main part used: vacuum tubes, transistors, integrated circuits (IC), microprocessors and artificial intelligence (AI).
• Devices are grouped as input, output and storage. Ports are the sockets where devices connect to the computer.

1. What is a computer?

A computer is an electronic device that follows instructions (a program) to work on data and give useful results. Data means raw facts. Information means data that has been processed and has meaning.

Main features:

• Speed: it works in a fraction of a second.
• Accuracy: errors come mostly from wrong input or wrong programs ("garbage in, garbage out").
• Storage: it can keep a large amount of data.
• Diligence: it does not get tired.
• Versatility: it can do many types of work.

Main parts of a computer system:

• Hardware: parts you can touch (keyboard, monitor, CPU).
• Software: programs and instructions.
• CPU (Central Processing Unit): the brain. It has the Arithmetic Logic Unit (ALU) for calculations and logic, the Control Unit (CU) for directing work, and registers for tiny, very fast storage.
• Memory: RAM (temporary, working memory) and ROM (permanent, read-only memory).

2. A short history of computing

Before electronic computers, people used tools and machines to count and calculate.

Some points to note:

• Babbage's Analytical Engine had the main ideas of a modern computer: an input, a "store" (memory), a "mill" (processor) and an output.
• John von Neumann gave the stored-program concept: both data and program are kept in memory.
• The word "computer" first meant a person who did calculations.

3. Generations of computers

Key notes:

• Intel 4004 (1971) is known as the first microprocessor.
• ICs were invented in the late 1950s; they pack many transistors on one chip.
• First generation examples: ENIAC, UNIVAC. Third generation example: IBM-360 series. Fourth generation example: the IBM PC and Apple computers.
• Each generation brought smaller size, higher speed, lower cost and lower power use.

4. Types of computers

By size and power

Microcomputers include desktops, laptops, tablets and smartphones.

By working method

• Analog: works on continuous signals (for example, a speedometer or a thermometer).
• Digital: works on 0s and 1s (a normal computer).
• Hybrid: has features of both (used in hospitals and in some control systems).

India's PARAM series of supercomputers was developed by the Centre for Development of Advanced Computing (C-DAC) at Pune.

5. Input devices

Input devices send data into the computer.

• Keyboard: typing letters, numbers and commands.
• Mouse: pointing and clicking.
• Scanner: copies a paper page into the computer as an image.
• Microphone: records sound.
• Webcam: takes live video or photos.
• Joystick: used in games.
• Light pen and touch screen: point or touch on the display.
• Barcode reader: reads lines (a bar code) on products.
• OMR (Optical Mark Reader): reads marked bubbles, as in exam answer sheets.
• OCR (Optical Character Recognition): reads printed text as editable text.
• MICR (Magnetic Ink Character Recognition): reads cheque numbers in magnetic ink.
• Biometric devices: fingerprint and iris scanners.

6. Output devices

Output devices show results to the user.

• Monitor: screen display (CRT, LCD, LED). It is also called a VDU (Visual Display Unit).
• Printer: gives a printed copy (hard copy).
• Impact printers (dot matrix) strike the paper.
• Non-impact printers (laser, inkjet) do not strike the paper.
• Plotter: draws large drawings (maps, designs).
• Speaker: gives sound.
• Projector: shows the display on a large screen.

A soft copy is the output seen on the screen. A hard copy is a printed copy.

7. Storage devices

Primary memory is inside or very close to the CPU: RAM and ROM (and cache memory, which is very fast).

Secondary storage keeps data for a long time.

Units of storage: 1 bit is the smallest unit; 8 bits = 1 byte; 1024 bytes = 1 kilobyte (KB); 1024 KB = 1 megabyte (MB); 1024 MB = 1 gigabyte (GB); 1024 GB = 1 terabyte (TB).

8. Ports and connectors

A port is a socket on the computer where a cable or device is attached.

9. How a computer works (the basic cycle)

• 1. Input: data is entered through a keyboard, mouse or other device.
• 2. Processing: the CPU fetches an instruction from memory, decodes it, and executes it. This is the fetch-decode-execute cycle.
• 3. Storage: results are kept in memory or on a disk.
• 4. Output: results are shown on the screen or printed.

The computer works with the binary system, which has only two digits, 0 and 1. Each 0 or 1 is a bit. Letters, numbers, pictures and sound are all changed to bits inside the machine. Cache memory is a very small and very fast memory between the CPU and RAM; it keeps the data that the CPU uses often.

Speed of a processor is measured in hertz (Hz), usually in gigahertz (GHz). A computer with more cores can do more tasks at the same time.

Exam traps

• RAM is temporary (volatile); ROM is permanent. RAM data is lost when power is off.
• Hardware vs software: touchable parts are hardware.
• Babbage is the father of the computer; Ada Lovelace is the first programmer.
• Transistors belong to the second generation; ICs to the third; microprocessors to the fourth.
• Input vs output: scanner is input; plotter, speaker and monitor are output.
• Hard copy and soft copy: printed vs on-screen.
• OMR reads marks; OCR reads characters; MICR reads magnetic ink numbers.
• Bit and byte: 1 byte = 8 bits.

One-liners

• 1. The CPU is the brain of the computer.
• 2. ALU does arithmetic and logic work.
• 3. RAM is volatile; ROM is non-volatile.
• 4. Charles Babbage is the father of the computer.
• 5. Ada Lovelace is the first programmer.
• 6. The first generation used vacuum tubes.
• 7. The second generation used transistors.
• 8. The third generation used integrated circuits.
• 9. The fourth generation used microprocessors.
• 10. Fifth generation work is linked to artificial intelligence.
• 11. A supercomputer is the fastest type of computer.
• 12. USB stands for Universal Serial Bus.

Practice questions

1. Who is called the Father of the Computer?

   1. Blaise Pascal
   2. Herman Hollerith
   3. Charles Babbage
   4. Alan Turing
   Answer

   C. Charles Babbage

   Babbage designed the Analytical Engine.

2. Who is regarded as the first programmer?

   1. John Napier
   2. Grace Hopper
   3. Charles Babbage
   4. Ada Lovelace
   Answer

   D. Ada Lovelace

   Ada Lovelace wrote programs for the Analytical Engine.

3. First generation computers used

   1. transistors
   2. vacuum tubes
   3. microprocessors
   4. integrated circuits
   Answer

   B. vacuum tubes

   Vacuum tubes were the main part in the first generation.

4. Second generation computers used

   1. transistors
   2. integrated circuits
   3. AI chips
   4. vacuum tubes
   Answer

   A. transistors

   Transistors replaced vacuum tubes.

5. Third generation computers used

   1. integrated circuits
   2. vacuum tubes
   3. transistors
   4. punched cards only
   Answer

   A. integrated circuits

   ICs pack many transistors on one chip.

6. Fourth generation computers used

   1. transistors
   2. microprocessors
   3. relays
   4. vacuum tubes
   Answer

   B. microprocessors

   Microprocessors (VLSI) mark the fourth generation.

7. Fifth generation computing is linked to

   1. magnetic drums
   2. vacuum tubes
   3. artificial intelligence
   4. punched cards
   Answer

   C. artificial intelligence

   AI and parallel processing are its focus.

8. Which was the first microprocessor?

   1. Core i3
   2. Intel 8086
   3. Pentium
   4. Intel 4004
   Answer

   D. Intel 4004

   Intel 4004 was released in 1971.

9. The brain of the computer is the

   1. Monitor
   2. Printer
   3. CPU
   4. Keyboard
   Answer

   C. CPU

   The CPU controls and processes everything.

10. ALU stands for

    1. Arithmetic Logic Unit
    2. Advanced Logic Unit
    3. Arithmetic Link Unit
    4. Analog Logic Utility
    Answer

    A. Arithmetic Logic Unit

    The ALU does arithmetic and logical operations.

11. Which memory loses its content when power is switched off?

    1. Pen drive
    2. RAM
    3. Hard disk
    4. ROM
    Answer

    B. RAM

    RAM is volatile.

12. Which memory is permanent and read-only?

    1. Register
    2. Cache
    3. RAM
    4. ROM
    Answer

    D. ROM

    ROM keeps its data without power.

13. Which of these is an input device?

    1. Speaker
    2. Monitor
    3. Scanner
    4. Plotter
    Answer

    C. Scanner

    A scanner sends images into the computer.

14. Which of these is an output device?

    1. Plotter
    2. Scanner
    3. Mouse
    4. Keyboard
    Answer

    A. Plotter

    A plotter draws output on paper.

15. A printed copy of output is called a

    1. cache
    2. backup
    3. soft copy
    4. hard copy
    Answer

    D. hard copy

    A soft copy is the on-screen display.

16. 1 byte equals how many bits?

    1. 4
    2. 16
    3. 10
    4. 8
    Answer

    D. 8

    A byte has 8 bits.

17. 1 kilobyte equals

    1. 1024 bytes
    2. 1000 bytes only
    3. 512 bytes
    4. 8 bytes
    Answer

    A. 1024 bytes

    Computer units are based on 1024.

18. OMR is used to read

    1. bar codes
    2. marked bubbles on answer sheets
    3. magnetic ink numbers
    4. handwriting
    Answer

    B. marked bubbles on answer sheets

    OMR reads marks.

19. MICR is mainly used in

    1. video editing
    2. radio
    3. banks for cheques
    4. games
    Answer

    C. banks for cheques

    MICR reads numbers printed in magnetic ink.

20. OCR converts

    1. text to sound
    2. printed text images to editable text
    3. files to folders
    4. audio to video
    Answer

    B. printed text images to editable text

    OCR recognises characters.

21. India's PARAM supercomputers were developed by

    1. BARC
    2. DRDO
    3. C-DAC
    4. ISRO
    Answer

    C. C-DAC

    The Centre for Development of Advanced Computing, Pune, built PARAM.

22. Which type of computer is the fastest and most powerful?

    1. Supercomputer
    2. Minicomputer
    3. Microcomputer
    4. Mainframe
    Answer

    A. Supercomputer

    Supercomputers handle very heavy tasks.

23. A laptop is an example of a

    1. mainframe
    2. supercomputer
    3. analog computer
    4. microcomputer
    Answer

    D. microcomputer

    Personal computers are microcomputers.

24. A computer that works on continuous signals is

    1. hybrid
    2. analog
    3. digital
    4. binary
    Answer

    B. analog

    A speedometer is an analog device.

25. A computer that uses features of both analog and digital is

    1. hybrid
    2. mini
    3. mainframe
    4. micro
    Answer

    A. hybrid

    Hybrid computers combine both.

26. Which port is widely used for pen drives?

    1. PS/2
    2. HDMI
    3. VGA
    4. USB
    Answer

    D. USB

    USB connects many devices.

27. HDMI carries

    1. only text
    2. only power
    3. video and sound
    4. only mouse signals
    Answer

    C. video and sound

    HDMI sends high-quality digital video and audio.

28. An Ethernet (RJ-45) port is used for

    1. a headphone
    2. a wired network connection
    3. a pen drive
    4. a printer power
    Answer

    B. a wired network connection

    Ethernet cables connect to wired networks.

29. Which of these is secondary storage?

    1. Register
    2. RAM
    3. Cache
    4. Hard disk
    Answer

    D. Hard disk

    Secondary storage keeps data for a long time.

30. Which of these uses a laser to read data?

    1. DVD
    2. Hard disk
    3. Magnetic tape
    4. Floppy
    Answer

    A. DVD

    Optical discs use a laser.

31. A pen drive is an example of

    1. primary memory
    2. flash storage
    3. magnetic storage
    4. optical storage
    Answer

    B. flash storage

    Flash memory has no moving parts.

32. Who gave the stored-program concept?

    1. John Napier
    2. Charles Babbage
    3. John von Neumann
    4. Herman Hollerith
    Answer

    C. John von Neumann

    Programs and data are kept in memory.

33. Which machine used punched cards for census data?

    1. Abacus
    2. Hollerith's tabulating machine
    3. Pascaline
    4. Napier's bones
    Answer

    B. Hollerith's tabulating machine

    Herman Hollerith's machine used punched cards.

34. The Pascaline was a

    1. printer
    2. loom
    3. electronic computer
    4. mechanical adding machine
    Answer

    D. mechanical adding machine

    It was invented by Blaise Pascal.

35. Which first generation computer name is correct?

    1. Apple II
    2. Pentium
    3. ENIAC
    4. IBM-360
    Answer

    C. ENIAC

    ENIAC used vacuum tubes.

36. Which device is used for biometric login?

    1. Fingerprint scanner
    2. Plotter
    3. Projector
    4. Speaker
    Answer

    A. Fingerprint scanner

    A fingerprint scanner reads a person's fingerprint.

37. A dot matrix printer is a

    1. plotter
    2. non-impact printer
    3. laser printer
    4. impact printer
    Answer

    D. impact printer

    It strikes the paper to print.

38. Consider the statements about memory. 1. RAM is volatile. 2. ROM loses its data when power is off.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    ROM is non-volatile.

39. Consider the statements about generations. 1. Vacuum tubes were used in the fourth generation. 2. Transistors were used in the second generation.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    B. 2 only

    Vacuum tubes belong to the first generation.

40. Consider the statements. 1. A scanner is an input device. 2. A speaker is an input device.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    A speaker is an output device.

41. Consider the statements about history. 1. Ada Lovelace invented the Pascaline. 2. Charles Babbage designed the Analytical Engine.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    B. 2 only

    The Pascaline was invented by Pascal.

42. Consider the statements about storage units. 1. 1 byte is 8 bits. 2. 1 megabyte is smaller than 1 kilobyte.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    A megabyte is larger than a kilobyte.

43. Consider the statements. 1. VGA is a newer digital port that replaced HDMI. 2. HDMI can carry both video and audio.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    B. 2 only

    VGA is older than HDMI.

44. Consider the statements. 1. The CPU contains the ALU and the control unit. 2. The ALU controls the movement of data between devices.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    The control unit directs the work; the ALU does calculations.

45. Which of the following is a sign of a later generation of computers?

    1. Slower speed
    2. Bigger size and higher heat
    3. Smaller size and lower cost
    4. More vacuum tubes
    Answer

    C. Smaller size and lower cost

    Each generation became smaller, faster and cheaper.