Understanding Computer Architecture: A Comprehensive Overview

This assignment provides a comprehensive introduction to computer architecture, suitable for a Class 6 level. It begins by defining a computer system and its components, including both hardware and software. The assignment then delves into the concept of computer architecture, explaining how different hardware pieces interact. It explores the evolution of computers, highlighting the von Neumann architecture and the fetch-decode-execute cycle. The central processing unit (CPU) and its components, such as the ALU, control unit, cache, registers, buses, and clock, are explained in detail. The assignment also covers computer memory, differentiating between primary (RAM and ROM) and auxiliary (secondary) memory, and provides examples of storage devices. The assignment includes exercises such as expanding abbreviations, true/false questions, unjumbling words, and fill-in-the-blanks to reinforce learning. Video tutorials and a glossary are provided as supplementary resources.

Subject: Computer Studies Topic: Introduction to Computer Architecture Class: 6
Learning Objectives:
• What is a Computer System?
• What are the components of a Computer System?
• What is Computer Architecture?
• How the earlier computers were like?
• What is von Neumann Architecture?
• What is the Fetch-Decode-Execute cycle?
• What is Central Processing Unit (CPU) or Processor?
• What are the components of a CPU?
o Arithmetic and Logic Unit (ALU)
o Control Unit (CU)
o Cache
o Registers
o Buses
o Clock
• What is Computer Memory?
o Main or Primary Memory
o Auxiliary or Secondary Memory
• Units of Computer Memory
Explanation:
What is a computer?
A computer is a programmable device that stores, retrieves, and processes data.
Self- paced Learning Plan

What are the components of a Computer System?
Computers are built of various components:
• Software
• Hardware
Software is any program (a set of instructions) that
runs on a computer system.
Computer hardware is the physical components that a
computer system requires to function. All the input
devices and the output devices together constitute the
computer hardware. All these components must communicate with each other and provide a necessary service
to the user. The hardware of a computer includes:
What is Computer Architecture?
A computer is a complex device containing many sub-systems. Each sub-system is a piece of computer
hardware (or part of a piece of computer hardware.) How these pieces interact is called the "Computer
Architecture".
How the earlier computers were like?
Before 1943, computers like the one shown in the
adjacent picture did not store their programs in memory,
instead a series of switches had to be manually turned or
read from a paper stream. These instructions would then
be read one at a time. If you required, the computer to do
something else you would then have to manually turn all
the switches into another combination.
This situation was far from ideal, time consuming and
prone to mistakes.
What is von Neumann Architecture?
• Mathematician John von Neumann and his colleagues proposed the von Neumann architecture in 1945.
• It stated that a computer consists of:
o a processor with an arithmetic and logic unit (ALU) and a control unit (CU)
o a memory unit that can communicate directly with the processor using connections called buses
o connections for input/ output devices and
o a secondary storage for saving and backing up data.
• The central computation concept of this architecture is that instructions and data are both loaded into
the same memory unit.

What is the Fetch-Decode-Execute cycle?
• With program instructions and data now being stored in the same memory, a process had to be designed
to allow CPUs (Central Processing Units) to find the correct instruction and execute it. The process
that was designed is known as the Fetch-Decode-Execute cycle.
• These three operations are constantly repeated by the CPU as the computer is running that allows the
CPU to work through new instructions quickly and efficiently as they are required.
Fetch This operation is triggered by the CPU causing the next instruction and data to be 'fetched' from memory
(RAM).
Decode Once the CPU has fetched the instructions and data it will then translate them into instructions
understandable by the CPU.
Execute The CPU will then execute the instructions in a logical sequence.
What is Central Processing Unit (CPU) or Processor?
The Central Processing Unit (CPU) is the electronic circuit responsible for executing the instructions of a
computer program. It is sometimes referred to as the microprocessor or processor. The CPU is often termed
as the “Brain” of a computer system.
What are the components of a CPU or Processor?
The central processing unit (CPU) consists
of six main components:
• Arithmetic and Logic Unit (ALU)
• Control Unit (CU)
• Cache
• Registers
• Buses
• Clock
All components work together to allow processing and system control.
Among the most well-known processor
manufacturers in the world are Intel, AMD,
Qualcomm, Motorola, Samsung, and IBM.

What is Arithmetic and Logic Unit (ALU)?
The main function of the ALU is to perform arithmetic and logical operations (decisions). The ALU is where
calculations are done and where decisions are made.
What is Control Unit (CU)?
The CU provides several functions:
• It fetches, decodes, and executes instructions.
• It issues control signals that control hardware.
• It moves data around the system.
What is Cache?
• Cache is a small amount of high-speed random-access memory built directly within the processor.
• It is used to temporarily hold data and instructions that the processor is likely to reuse.
• This allows for faster processing as the processor does not have to wait for the data and instructions to
be fetched from the RAM.
What are Registers?
• Registers are small amounts of high-speed memory contained within the CPU.
• They are used by the processor to store small amounts of data needed during processing, such as:
o the address of the next instruction to be executed
o the current instruction being decoded
o the results of calculations
What are Buses?
• A computer system consists of several internal and external components. These components are
physically interconnected and communicate with one another through a network of wires across the
computer system. These wires are referred to as computer buses.
• These computer buses can be in the form of wired cables or electrical wires embedded in the computer
motherboard.
• Technical features of these buses such as bus width and bus speed impact the system performance.
What is Clock?
• In general, the clock refers to a microchip that regulates the timing and speed of all computer functions.
• The internal clock or real-time clock (RTC) sends out a regular electrical pulse which synchronises
(keeps in time) all the components.
• The frequency of the pulses is known as the clock speed.
• The higher the frequency of the CPU's clock, the more logical operations it can perform per second.
So, as the frequency of the CPU's clock increases, the time required to perform tasks decreases.
• Clock speeds are measured in MHz, 1 MHz representing 1 million cycles per second.

What is Computer Memory?
• Computer memory is the storage space in the computer, where data to be processed and instructions
required for processing are stored.
• Computer memory is divided into main (or primary) memory and auxiliary (or secondary) memory.
• Main memory holds instructions and data when a program is executing, while auxiliary memory holds
data and programs not currently in use and provides long-term storage.
Main or Primary Memory
Primary Memory is of two types: RAM and ROM.
➢ RAM (Volatile Memory)
o It is a volatile memory. It means it does not store data or
instructions permanently.
o When you switch on the computer the data and
instructions from the hard disk are stored in RAM.
o CPU utilizes this data to perform the required tasks. As
soon as you shut down the computer the RAM loses all the
data.
➢ ROM (Non-volatile Memory)
o It is a non-volatile memory. It means it does not
lose its data or programs that are written on it at
the time of manufacture.
o So, it is a permanent memory that contains all
important data and instructions needed to
perform important tasks like the boot process.
Auxiliary or Secondary Memory
• The secondary storage devices which are built into the computer or connected to the computer are
known as a secondary memory of the computer. It is non-volatile, so permanently stores the data even
when the computer is turned off or until this data is overwritten or deleted.
• The CPU can't directly access the secondary memory. First, the secondary memory data is transferred
to primary memory then the CPU can access it.
• Some examples of storage devices (secondary memory) are: Hard Disk Drive (HDD), Solid State Drive
(SSD), Compact Disk (CD), Digital Versatile Disk (DVD), Blu-ray Disk, Pen Drive, Flash Drive, etc.

Units of Computer Memory:
Video Tutorials:
1. How computers work: CPU Memory Input Output
https://bit.ly/3lqRVEP
2. How do CPUs work?
https://bit.ly/3l5FoX2
3. How does computer memory work?
https://bit.ly/3w4D3SC

Glossary:
bit short for binary digit; the smallest unit of data in a computer
bus a communication system that transfers data between components inside a computer, or
between computers
byte short for binary term; a group of four bits
cache a reserved storage location that collects temporary data to help websites, browsers, and
apps load faster
clock a microchip that regulates the timing and speed of all computer functions
clock speed rate at which a processor completes its total processing cycle in one second
data raw facts or figures
hardware (h/w) the physical components that a computer system requires to function
information processed data
memory the storage space in the computer, where data to be processed and instructions required
for processing are stored
motherboard the backbone that ties the computer's components together at one spot and allows them
to talk to one another
peripherals broad name given to different devices that can be connected to a computer to enhance
its features and functionality
processor a small chip that is responsible for carrying out instructions to run a computer system
RAM a type of memory that is volatile and can be accessed randomly; it temporarily stores
(remembers) everything currently running on a device
register a type of memory that access instructions immediately; it receives, stores, and transfers
data required for processing information
ROM A type of memory that is non-volatile; it contains some important instructions or
program data that are required to start or boot a computer
software (s/w) a set of related programs to perform a task

Exercise:
1. Expand the following:
a. ALU: …………………………………………………………………………………..
b. BIT: …………………………………………………………………………………..
c. BYTE: …………………………………………………………………………………..
d. CD: …………………………………………………………………………………..
e. CPU: …………………………………………………………………………………..
f. CU: …………………………………………………………………………………..
g. DVD: …………………………………………………………………………………..
h. HDD: …………………………………………………………………………………..
i. RAM: …………………………………………………………………………………..
j. ROM: …………………………………………………………………………………..
k. SDD: …………………………………………………………………………………..
2. State whether the following statements are True or False:
a. ROM is volatile in nature. ………………
b. A CD has a higher storage capacity than a DVD. ………………
c. Hardware and software can work independently. ………………
d. The CPU can directly access the second memory. ………………
e. Registers make a communication system that transfers data between components inside a
computer, or between computers. ………………
3. Unjumble the jumbled words:
a. ABDEHMORRT : ………………………………………………
b. ACCEH : ………………………………………………
c. AADEEHRW : ………………………………………………
d. AEFORSTW : ………………………………………………
e. CEOOPRRSS : ………………………………………………
f. EEGIRRST : ………………………………………………
g. MREYMO : ………………………………………………

4. Fill in the blanks:
a. ……………… are raw facts or figures.
b. A ……………… is the smallest unit of data in a computer.
c. The ………………. is responsible for performing arithmetic and logical operations (decisions).
d. Computer memory is divided into ……………….. memory and …………………….. memory.
e. The ………. refers to a microchip that regulates the timing and speed of all computer functions.
f. Mathematician ……………………………………………. and his colleagues proposed the
von Neumann architecture in the year …………….

Rate your learning (Select 5 for highest and 1 for lowest):
1. I understand what a computer system is.
5 4 3 2 1
2. I understand what the components of a computer system are.
5 4 3 2 1
3. I understand what Computer Architecture means.
5 4 3 2 1
4. I understand what the von Neumann Architecture is.
5 4 3 2 1
5. I understand what the Fetch-Decode-Execute Cycle is.
5 4 3 2 1
6. I understand what the Central Processing Unit (CPU) is.
5 4 3 2 1
7. I understand what the different components of the CPU are.
5 4 3 2 1
8. I understand what the roles of different components of the CPU are.
5 4 3 2 1
9. I understand what the Computer Memory is.
5 4 3 2 1
10. I understand the classification of Computer Memory.
5 4 3 2 1
11. I need more help for the following sub- topic (s) in this lesson:
…………………………………………………….
…………………………………………………….
…………………………………………………….