Part 4: Computer Architecture and Organization

 Computer Architecture

-It is the design of a computer, including how its components work together.

-Focuses on what a computer does and how it is designed to do it.

 

Computer Organization

 

 - It deals with the physical components of a computer and how they are connected.

 -Focuses on how the computer hardware works internally.

 

Easy way to remember:

 Architecture = Plan/design (conceptual).

 Organization = Actual hardware & connections (practical).

Page number 43- Difference between Computer Architecture and Computer Organization

 

Basic Components of a Computer

 

1. Input Unit – Takes data from the user (keyboard, mouse).

2. Central Processing Unit (CPU) – The brain of the computer. It has three parts:

 

    ALU (Arithmetic Logic Unit): Does calculations & comparisons.

    CU (Control Unit): Directs all operations in the computer.

    Registers: Small, fast storage inside the CPU.

3. Memory Unit (Storage) – Stores data and instructions.

    Primary Memory: RAM (temporary), ROM (permanent).

    Secondary Memory: Hard drives, SSDs (long-term storage).

4. Output Unit – Shows results to the user (monitor, printer).

 

 Input/Output Devices (I/O Devices)

 

Input Devices

- Devices that allow the user to give data to the computer.

 Examples: Keyboard, mouse, scanner, microphone, camera.

 

Functions:

 Convert human-readable data into machine-readable data.

 

Output Devices

- Devices that show or present processed data to the user.

 Examples: Monitor, printer, speaker, projector.

 

Functions:

 Convert machine-readable data back into human-readable form.

 

Book’s Exercise Page Number 73

 

 Multiple Choice Questions (MCQs)

 

a) ……………………is also called as brain of computer

i.Motherboard

ii.CPU

iii.RAM

iv Monitor

 

b) Which of the following is an output device?

i.Microphone

ii.Scanner

iii.Plotter

iv.QR Code Scanner

 

c) ………… can be erased by ultraviolet light and reprogrammed.

i.PROM

ii. EPROM

iii.EEPROM

iv RAM

 

d) ………… is a memory between CPU and main memory

i.RAM

ii.Cache

iii.ROM

iv. Secondary

 

e) The speed of hard disk is measured in……

i. mgh

ii khz

iii.rpm

iv. rem

 

f) A ……… stored in memory is used to read handwritten or printed text to make a digital image.

i.Touch pad

ii.Printer

iii.Laser beam

iv. Scanner

 

g) Which hardware device is used to store data for long period of time?

i. Secondary storage

ii. CPU

iii. Data input

iv. RAM chip

 

h) The box that contains the central electronic components of the computer is the

i. Input device

ii. Peripheral

iii. System unit

iv. Motherboard

 

i) The new ……… integrates the function of a processor, memory and video on a single chip.

i. Chip processor

ii. System on a chip

iii.Power processor

iv. Micro processor

 

 

 Short Answer Questions

 

a) What is computer system? Write down the main units of computer system.

A computer system is a combination of hardware and software that performs input, processing, storage, and output of data.

 

Main units:

1. Input Unit

2. Central Processing Unit (CPU)

3. Memory Unit

4. Output Unit

5. Storage Unit

 

b) Mention the functions performed by ALU.

ALU (Arithmetic Logic Unit) performs:

1. Arithmetic operations (addition, subtraction, multiplication, division)

2. Logical operations (AND, OR, NOT, comparison)

 

c) Define cache memory with its advantage.

Cache memory is a small, high-speed memory located between CPU and RAM.

Advantage: It increases processing speed by storing frequently used data.

 

d) Convert as indicated:

 5 MB = 5 × 1024 KB = 5120 KB

 120 KB = 120 × 1024 bytes = 122880 bytes

 12 GB = 12 × 1024 MB = 12288 MB

 32 MHz = 32 × 10⁶ Hz = 32,000,000 Hz

 

e) Define computer hardware with its importance in computer system.

Hardware refers to the physical parts of a computer (CPU, monitor, keyboard).

Importance: Hardware is needed to run software and perform all computer operations.

 

f) What is microprocessor? How does it work? Explain.

A microprocessor is a single-chip CPU that performs all processing tasks.

Working: It fetches instructions from memory, decodes them, executes operations, and stores results.

 

g) What is computer memory? Write its major classification.

Memory is used to store data and instructions temporarily or permanently.

Types:

1. Primary Memory – RAM, ROM

2. Secondary Memory – Hard disk, SSD, CD/DVD

3. Cache Memory – Small, fast memory for CPU

 

h) Why secondary memory is used for future storage? Explain with its types.

Secondary memory is used to store data permanently because primary memory (RAM) is temporary.

Types:

 Magnetic: Hard disk, Magnetic tape

 Optical: CD, DVD

 Solid State: SSD, USB drives

 

i) How computer mouse works? Who developed it?

A mouse detects movement on a surface and converts it into cursor movement on the screen.

Developer: Douglas Engelbart

 

j) What is a port? Explain its two types.

A port is a connection point on a computer to attach external devices.

Types:

1. Input Port – Receives data (e.g., USB for keyboard)

2. Output Port – Sends data (e.g., HDMI to monitor)

 

 3. Differentiate Between

 

a) Computer Organization vs Computer Architecture

Page number 43

 

b) Difference between Input Unit and Output Unit

 

1. The input unit is used to send data into the computer, while the output unit is used to display or send results out of the computer.

2. Input devices accept data and instructions from the user, but output devices give information to the user.

3. The input unit converts human-readable data into machine-readable form, whereas the output unit converts machine data into human-readable form.

4. Examples of input devices are keyboard, mouse, and scanner, while examples of output devices are monitor, printer, and speaker.

5. Without the input unit, a computer cannot receive commands, and without the output unit, it cannot show results.

 

c) Difference between RAM and ROM

 

Page number 52

 

d) Difference between Primary and Secondary Memory

 

1. Primary memory is used for temporary data storage, while secondary memory is used for permanent storage.

2. Primary memory includes RAM and ROM, while secondary memory includes hard disks, CDs, and pen drives.

3. Data in primary memory is lost when power goes off, but data in secondary memory stays safe even without power.

4. Primary memory is faster in speed, while secondary memory is slower.

5. Primary memory is more expensive and smaller in size, while secondary memory is cheaper and larger in capacity.

 

e) Difference between Magnetic Storage and Optical Storage

 

1. Magnetic storage uses magnetic patterns to store data, while optical storage uses laser light.

2. Magnetic devices include hard disks and magnetic tapes, while optical devices include CDs and DVDs.

3. Magnetic storage can be easily rewritten, while optical storage usually needs special equipment to rewrite.

4. Magnetic storage is faster in data access, while optical storage is slower.

5. Magnetic storage devices are more fragile to magnetic fields, but optical storage devices are less affected.

 

f) Difference between CD and DVD

 

Page number 57

g) Difference between Hard Disk Drive (HDD) and Solid State Drive (SSD)

 

1. An HDD uses magnetic spinning disks to store data, while an SSD uses flash memory chips.

2. HDDs are slower in data access, but SSDs are much faster.

3. HDDs are cheaper per GB, while SSDs are more expensive.

4. HDDs have moving parts, while SSDs have no moving parts.

5. SSDs are more durable and power-efficient, but HDDs are more likely to break from shocks.

 

h) Difference between Impact and Non-Impact Printers

 

1. Impact printers print by striking an ink ribbon on paper, while non-impact printers print without any contact.

2. Impact printers are noisy, but non-impact printers are quiet.

3. Examples of impact printers are dot matrix and daisy wheel, while non-impact printers include inkjet and laser printers.

4. Impact printers are slow and low quality, while non-impact printers are fast and high quality.

5. Impact printers can print multiple copies using carbon paper, but non-impact printers cannot do that.

 

4. Long Answer Questions

 

a) Block diagram of digital computer system

Page number 44

 

Functions:

 Input Unit: Receives data

 CPU: Processes data

 Memory Unit: Stores data temporarily

 Output Unit: Displays results

 Storage Unit: Stores data permanently

 

 

b) What is CPU? Explain its different components.

CPU is the brain of the computer.

Components:

1. ALU: Performs arithmetic & logical operations

2. CU: Controls all computer operations

3. Registers: Small storage inside CPU for fast access

 

c) What is an input device? Explain any four.

An input device is used to enter data into a computer.

Examples:

1. Keyboard: Enter text & commands

2. Mouse: Point & click

3. Scanner: Convert paper documents to digital

4. Microphone: Input sound

 

d) What is an output device? Explain any three.

An output device is used to display or present processed data.

Examples:

1. Monitor: Displays images & text

2. Printer: Prints documents & images

3. Speaker: Outputs sound

 

e) Explain with chart "Types of computer".