Fundamentals of Computer

Your SEE result will appear on a website the moment it is published. Your family pays the electricity bill with eSewa or Khalti, your bank balance changes the second cash comes out of an ATM, and a doctor in Kathmandu can read an X-ray taken in Dolakha. Behind every one of these is a computer. This lesson builds the words that all the later lessons use: what a computer is, how data differs from information, the four steps by which every computer works, what computers do very well, what they cannot do, and how they are used in Nepal.

1.1 Computer: definition; data, information and program; hardware and software

The word computer comes from the Latin word computare, which means "to calculate". The first computers really were giant calculators. A modern computer still calculates, but it also writes letters, shows films, plays music, guides aeroplanes and connects people across the world.

Every word in that definition matters. Electronic means it works with electric signals. Accepts data means it needs something to work on. Instructions means it does nothing by itself: a person must tell it what to do. Stores means it keeps its work for later. Information is what we want from it in the end.

Data and information

The marks a student gets in five subjects are data. Add them, work out the percentage and pick out the best subject, and you have information that a student, a parent or a teacher can act on.

Data	Information
raw, unprocessed facts and figures	processed, organised data
usually has no clear meaning by itself	has meaning and is useful
is the input of processing	is the output of processing
cannot be used directly to make a decision	helps in making decisions
example: 78, 66, 85, 92, 74	example: "Percentage 79%, best subject Science"

Program and software

A computer understands only exact, step-by-step instructions. An instruction is a single command such as "add these two numbers" or "print this line".

Software is of two broad kinds, which Lesson 5 studies in detail:

• System software runs the computer itself: the operating system (Windows, Linux, Android), device drivers and utility programs.
• Application software does a job for the user: a word processor, a web browser, a photo editor, a school's result program, a game.

Software can be obtained in two ways. Some is free: LibreOffice, Mozilla Firefox and VLC can be downloaded legally from their own websites. Other software must be bought with a licence, such as Microsoft 365. Copying or using paid software without a licence is software piracy, an offence under Nepal's Copyright Act, 2059.

Hardware

1Scanner (input)2CPU or microprocessor (processing)3Main memory, RAM4Expansion cards, such as a graphics card5Power supply unit6Optical disc drive (CD or DVD)7Hard disk drive (storage)8Motherboard, which joins all the parts9Speaker (output)10Monitor (output)11System software: the desktop and its windows12Application software: a game13Keyboard (input)14Mouse (input)15External hard disk (storage)16Printer (output)

Hardware	Software
physical parts of the computer	programs that tell the hardware what to do
can be seen and touched	can be seen working, but cannot be touched
made in factories from metal, plastic and silicon	written by programmers in programming languages
wears out with use and is damaged by heat, dust or a fall	does not wear out, but can be damaged by viruses or bugs
a broken part is repaired or replaced	a fault is fixed by updating or reinstalling
examples: keyboard, RAM, hard disk, printer	examples: Windows 11, Android, MS Word, Chrome

Hardware and software depend on each other. Hardware without software is like a new guitar that nobody can play: everything is there, but nothing happens. Software without hardware has nowhere to run. A third part is the user, the person who gives instructions and uses the results; some books call users liveware or humanware.

1.2 Working principle of a computer: the IPOS cycle

Every computer, from a calculator to a supercomputer, works in the same four steps: Input, Process, Output and Storage. This is called the IPOS cycle (some books say IPO cycle and treat storage separately).

1. Input. Giving data and instructions to the computer is input. The devices used for it are input devices: keyboard, mouse, microphone, scanner, webcam, touch screen, barcode reader, fingerprint reader. Input devices change what we type, say or show into electric signals that the computer can use.

2. Process. Working on the data — calculating, comparing, sorting — is processing. It is done by the CPU (Central Processing Unit), often called the brain of the computer. The CPU has two main parts:

• the Control Unit (CU), which controls and coordinates all the other parts: it fetches each instruction, works out what it means and tells the right unit to carry it out, like a traffic police officer directing traffic;
• the Arithmetic Logic Unit (ALU), which does arithmetic (adding, subtracting, multiplying, dividing) and logic (comparing: is 92 greater than 85? are two passwords equal?).

The CPU also has tiny, very fast memory cells called registers that hold the numbers it is working on at that instant.

3. Output. Giving the results to the user is output. Output devices include the monitor, printer, speaker, headphones and projector. Output on a screen is called a soft copy; output printed on paper is a hard copy.

4. Storage. Keeping data, programs and results is storage.

• Primary memory (main memory) works directly with the CPU. RAM (Random Access Memory) holds the programs and data in use right now; it is fast but temporary — everything in it is lost when the power goes off. ROM (Read Only Memory) holds the permanent start-up instructions.
• Secondary storage keeps work permanently, even with the power off: hard disk, SSD (solid-state drive), pen drive, memory card, CD/DVD, and online (cloud) storage such as Google Drive.

1.3 Characteristics of a computer

The characteristics (features) of a computer are the qualities that make it so useful. Six are named in the syllabus.

1. Speed. A computer works with electric signals that travel through its circuits almost at the speed of light, so it does in seconds what would take a person months. Its speed is measured in tiny fractions of a second.

Unit	Symbol	Part of a second	Power of 10
millisecond	ms	one thousandth	10^{-3} s
microsecond	μs	one millionth	10^{-6} s
nanosecond	ns	one billionth	10^{-9} s
picosecond	ps	one trillionth	10^{-12} s
femtosecond	fs	one quadrillionth	10^{-15} s

A processor's speed is given by its clock speed in gigahertz (GHz). A 3 GHz processor's clock ticks three thousand million times every second, and the processor can take at least one step on every tick.

2. Accuracy. A computer does not make mistakes in calculation. If it is given correct data and a correct program, its result is correct every time. Wrong results come from wrong input or a wrong program, never from the computer "getting tired". This is summed up as GIGO — Garbage In, Garbage Out. A mistake in a program is called a bug.

3. Diligence. A computer can do the same work again and again for hours without becoming tired, bored or careless, and its speed and accuracy stay the same. Printing 10,000 admit cards or checking every student's marks in a district examination is the same to it as doing the first one.

4. Versatility. One computer can do many different kinds of work: write a letter, calculate a budget, edit a photo, play a film, run a video class and help you learn programming. It changes its job simply by running different software.

5. Storage. A computer can store a huge amount of data — books, songs, photos, films, records of millions of people — and find any item in a moment. Storage is measured in bytes; one byte holds one character such as A.

Unit	Equal to
1 bit	a single 0 or 1
1 nibble	4 bits
1 byte (B)	8 bits
1 kilobyte (KB)	1024 bytes
1 megabyte (MB)	1024 KB
1 gigabyte (GB)	1024 MB
1 terabyte (TB)	1024 GB

6. Automation. Once a program is started, the computer carries out the whole task by itself, step after step, without a person giving each command. A phone backs up photos every night, a bank adds interest to every account at the end of the month, and a washing machine runs its whole wash cycle on its own.

Characteristic	Meaning in one line	Example in Nepal
Speed	works in milliseconds and nanoseconds	NEB results for lakhs of students are ready in days
Accuracy	correct result for correct input (GIGO)	a supermarket bill adds up 40 items with no error
Diligence	works for hours without tiring or slowing	a bank's server runs all day and all night
Versatility	does many kinds of work	one school computer for typing, accounts and classes
Storage	keeps huge amounts of data for a long time	the National ID card database of crores of citizens
Automation	finishes a task by itself once started	eSewa sends a receipt automatically after payment

1.4 Limitations of a computer and its effects on society

Limitations

For all its power, a computer has clear limits.

• No IQ of its own. It cannot think or decide by itself. It does only what its program tells it. Even artificial intelligence tools such as chatbots follow patterns learned from data; they can give confident but wrong answers and do not understand the world as people do.
• No feelings. It has no emotions, common sense or sense of right and wrong. It cannot judge whether a task is kind or harmful.
• Needs instructions. Without a program it can do nothing at all, and it cannot correct a wrong program by itself.
• Depends on correct input (GIGO). Wrong data gives wrong results.
• Needs electricity. It stops when the power goes off (unless it has a battery or UPS), and unsaved work in RAM is lost.
• Can fail or be attacked. A broken hard disk, a virus or a hacker can destroy data, so backups are needed.

Effects on society

Computers have changed how people in Nepal study, work, shop and talk to each other. The effects are both good and bad.

Positive effects	Negative effects
services become fast: bills, forms, results and tickets online	some jobs, such as manual typing and data entry, disappear
new jobs in IT, software, design and online business	eye strain, back and neck pain, poor sleep from long screen time
learning from anywhere: online classes, digital libraries	addiction to games, videos and social media
families keep in touch with relatives working abroad by video call	cyber crime: online fraud, hacking, cyber bullying
better health care: digital X-rays, hospital records	loss of privacy when personal data leak
records are kept safely and found in seconds	electronic waste (e-waste) that pollutes soil and water
businesses reach customers across the country	the digital divide: people without devices or internet fall behind

1.5 Uses of computers in Nepal

Because a computer is fast, accurate and versatile, it is used in almost every field. These are the fields named in the syllabus, with examples you can see around you.

Field	What computers do	Examples in Nepal
Education	teaching with multimedia, online classes, keeping student records, preparing results	school computer labs; OLE Nepal's free E-Pustakalaya digital library and E-Paath lessons; SEE and NEB results published online
Banking	keeping every account, ATMs, mobile and internet banking, digital payments	ATM cash withdrawal; mobile banking apps; eSewa, Khalti and FonePay QR payments
Health	diagnosis with CT scan, ultrasound, ECG and digital X-ray; patient records and billing; online appointments	hospital management software; telemedicine linking district hospitals to specialists in Kathmandu
Communication	email, video calls, social media, sending news	Viber and WhatsApp calls to relatives abroad; Nepal Telecom and Ncell use computers to connect every call
Agriculture	weather forecasts, market prices, farming advice, record keeping	the Department of Hydrology and Meteorology's forecasts; Kalimati market's daily wholesale prices read on a phone
Government	citizen records, online services, identity cards, taxes, census	the Nagarik App (2021); e-passports (since 2021); the biometric National Identity Card; online tax filing

Government (e-governance). The Nagarik App, launched in 2021, lets a citizen keep records such as citizenship, PAN number and voter ID on a phone and use some government services from home. Nepal began issuing e-passports on 17 November 2021; each has a chip holding the holder's details and photograph. The National Identity Card stores a photograph, fingerprints and an iris scan, so a person can be identified by computer.

Computers are used in many more fields: in business for billing, stock and VAT records; in transport for bus and flight tickets and traffic signals; in science for weather forecasting and space research; in entertainment for films, music and games; and in security for CCTV and fingerprint attendance.

Chapter summary

• A computer (Latin computare, to calculate) is an electronic machine that accepts data, processes it under a program, stores it and gives information.
• Data are raw facts; information is processed, meaningful data. A program is a set of instructions; software is a collection of programs.
• Hardware is the physical, touchable part; software tells it what to do. Neither works without the other.
• IPOS: input devices → CPU (control unit + arithmetic logic unit) → output devices, with storage (RAM temporary, secondary storage permanent) joined to the CPU.
• Characteristics: speed (ms, μs, ns), accuracy (GIGO), diligence, versatility, storage (8 bits = 1 byte, 1024 bytes = 1 KB) and automation.
• Limitations: no IQ, no feelings, needs a program, correct input and electricity. Effects on society are both positive and negative.
• Uses in Nepal: education, banking, health, communication, agriculture and government (Nagarik App, e-passport, National ID).

Practice questions

Group A — Objective (1 mark each)

1. The word "computer" comes from the Latin word computare, which means [1]ato storebto calculatecto typedto print
2. Raw facts and figures that have not been processed are called [1]ainformationbdatacsoftwaredoutput
3. A set of step-by-step instructions given to a computer is a [1]aprogrambdatumchardwaredresult
4. Which of these is hardware? [1]aWindows 11bMicrosoft WordcRAMdAndroid
5. Which part of the CPU decides whether 92 is greater than 85? [1]acontrol unitbarithmetic logic unitcRAMdinput unit
6. The ability of a computer to work for hours without tiring or losing accuracy is [1]aversatilitybdiligencecautomationdstorage
7. GIGO stands for [1]aGarbage In, Garbage OutbGood Input, Good OutputcGeneral Input, General OutputdGo In, Go Out
8. A touch screen is [1]aonly an input devicebonly an output devicecboth an input and an output deviceda storage device
9. Which of these is not a limitation of a computer? [1]ait needs electricitybit has no feelingscit cannot work without a programdit works at high speed
10. One nanosecond is [1]a10^{-3} sb10^{-6} sc10^{-9} sd10^{-12} s
11. The app in which Nepali citizens keep their citizenship, PAN and voter ID records is [1]aeSewabNagarik AppcViberdDaraz
12. Which of these keeps data even when the power is switched off? [1]aRAMbhard diskccontrol unitdregister
13. One kilobyte is equal to [1]a1000 bitsb1024 bytesc1024 bitsd8 bytes

Answers to Group A

1. (b) — computare means to calculate.

2. (b) — information is data after processing.

3. (a) — a program is a set of instructions.

4. (c) — RAM is a chip you can touch; the others are software.

5. (b) — comparing is a logical operation, done by the ALU.

6. (b) — diligence means working without tiredness or loss of accuracy.

7. (a) — wrong input gives wrong output.

8. (c) — it senses touch (input) and shows pictures (output).

9. (d) — high speed is a characteristic, not a limitation.

10. (c) — nano means one billionth.

11. (b) — the government's Nagarik App, launched in 2021.

12. (b) — RAM is temporary; the hard disk is secondary storage.

13. (b) — 1 KB = 1024 bytes.

Group B — Short answer (2 marks each)

1. Define computer. Write any two of its characteristics. [2]
2. Differentiate between data and information with one example of each. [2]
3. What is software? Name one system software and one application software. [2]
4. Write any two differences between hardware and software. [2]
5. What is GIGO? Explain with an example. [2]
6. Why is a computer called a diligent machine? [2]
7. Write any four limitations of a computer. [2]
8. Write the functions of the control unit and the arithmetic logic unit. [2]
9. A memory card holds 32 GB. How many 8 MB videos can it store? [2]
10. Write two uses of computers in banking in Nepal. [2]

Answers to Group B

1. A computer is an electronic machine that accepts data, processes it according to a program, stores it and gives meaningful information. Any two characteristics: speed, accuracy, diligence, versatility, storage, automation.

2. Data are raw, unprocessed facts with no clear meaning, e.g. the marks 78, 66, 85. Information is processed data that is meaningful and helps decisions, e.g. "percentage 79%, passed in first division".

3. Software is a collection of programs that tells the hardware what to do. System software: Windows 11 (or Android, Linux). Application software: Microsoft Word (or Chrome, VLC).

4. Hardware is the physical part that can be touched; software is a set of programs that cannot be touched. Hardware wears out and is replaced; software does not wear out and is fixed by updating or reinstalling. (Also: hardware is made in factories, software is written by programmers.)

5. GIGO means Garbage In, Garbage Out: if wrong data or a wrong program goes in, a wrong result comes out. Example: if a teacher types 29 instead of 92 for a Science mark, the computer correctly calculates a wrong percentage.

6. A computer can do the same task again and again for hours without becoming tired, bored or careless, and its speed and accuracy stay the same. This quality is diligence, so it is called a diligent machine.

7. It has no IQ and cannot think by itself; it has no feelings or common sense; it cannot work without a program and correct input (GIGO); it needs electricity. (It can also fail or be attacked by viruses.)

8. The control unit controls and coordinates all parts of the computer: it fetches and interprets instructions and tells each unit what to do. The ALU performs arithmetic operations (+, −, ×, ÷) and logical operations (comparisons such as greater than or equal to).

9. 32 GB = 32 × 1024 = 32,768 MB. Number of videos = 32,768 ÷ 8 = 4,096.

10. Any two: ATMs let customers withdraw cash at any time; every account and transaction is kept and updated by the bank's computers; mobile and internet banking let people transfer money from a phone; digital wallets and QR codes (eSewa, Khalti, FonePay) are used for payments.

Group C — Long answer (4 marks each)

1. Explain the working principle of a computer with a labelled block diagram. [4]
2. Explain any four characteristics of a computer with an example of each. [4]
3. Describe two positive and two negative effects of computers on society. [4]
4. Describe the use of computers in any four fields in Nepal, with an example for each. [4]
5. Anita pays her school fee through a mobile wallet. Identify the input, process, output and storage in this task. [4]

Answers to Group C

1. Draw the block diagram of Figure 2: Input → CPU (CU and ALU) → Output, with Storage joined both ways to the CPU. Input unit: accepts data and instructions from the user through devices such as the keyboard, mouse and microphone. Processing unit (CPU): the control unit directs every part and interprets instructions; the ALU does the calculations and comparisons. Output unit: gives the results through the monitor (soft copy), printer (hard copy) or speaker. Storage unit: RAM holds data being processed; secondary storage such as a hard disk or pen drive keeps data permanently. Together these steps form the IPOS cycle.

2. Any four, each with an example. Speed: a computer works in nanoseconds; a 3 GHz processor takes 3 billion steps per second. Accuracy: its calculations are correct when the input and program are correct (GIGO); a shop's bill of 40 items has no adding error. Diligence: it works for hours without tiring; it can print 10,000 admit cards with the same quality. Versatility: the same computer types letters, plays films and runs online classes. Storage: it keeps huge data, such as the records of every citizen with a National ID card. Automation: once started it finishes a task by itself, such as a phone backing up photos every night.

3. Positive: (i) services are faster and easier — bills, forms, results and tickets online save time and travel; (ii) learning and communication improve — online classes, digital libraries and video calls with relatives working abroad. Negative: (i) health problems such as eye strain and back pain, and addiction to games and social media; (ii) cyber crime and loss of privacy, such as online fraud and hacking. (Other valid points: new jobs, loss of some manual jobs, e-waste, the digital divide.)

4. Any four. Education: teaching with multimedia, online classes, student records and results — e.g. OLE Nepal's E-Pustakalaya, SEE results online. Banking: accounts, ATMs, mobile banking — e.g. QR payments with FonePay. Health: CT scan, ultrasound, ECG, hospital records — e.g. hospital billing software. Communication: email, video calls, social media — e.g. Viber calls to family abroad. Agriculture: weather forecasts and market prices — e.g. Kalimati's daily price list. Government: online services and identity records — e.g. the Nagarik App and e-passports.

5. Input: Anita opens the wallet app, enters or scans the school's details, types the amount and enters her PIN. Process: the wallet's computer checks the PIN, checks that her balance is enough, subtracts the amount from her account and adds it to the school's account. Output: a "payment successful" message and an e-receipt on her screen, and an SMS or notification to the school. Storage: the transaction, her new balance and the receipt are saved in the wallet company's database for future reference.