3.1 Central Processing Unit

Chapter 3
Hardware

3.1 The role of the CPU

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What are the physical components of a computer system?

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What is the component in a computer system that processes data and instructions?

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What is the cycle through which data and instructions are processed?

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What is the design of a computer system, including the components it contains?

Categorize

Options (9)

The part of the computer responsible for executing instructions and processing data.

This component is considered the "brain" of the computer

A single integrated circuit that can perform the functions of the central processing unit.

Refers to smaller-scale CPUs that are commonly found in embedded systems.

It is used for calculators.

A step-by-step process used by the CPU to execute instructions

The cycle that occurs repeatedly.

The design and structure of a computer system.

Describes the layout and organization of a computer's hardware components.

These are descriptions of various terms related to computer systems.

Categorize each description under the correct category:

CPU

Microprocessors

Fetch-Decode-Execute Cycle

Architecture

Open Ended

Give two examples of embedded systems.

Printer

video game console

​​Microwave Oven

Washing Machine

​Examples of embedded systems

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What is a computer system that performs a dedicated function?

A computer system that is very good at one think for example a Nintendo Switch or a washing machine.

Labelling

This is a basic representation of the fetch-decode-execute cycle.

Label each description.

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Fetch

Execute

Decode

For a instruction to be execute it needs to be fetch from the RAM.

This is the Fetch Stage

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Multiple Choice

What is the stage where the data is fetched from the RAM?

• Fetch stage
• Sorry, I am not a genius

• Execute stage
• decode stage

Reorder

Below are the steps involved in the fetch stage of the fetch-decode-execute cycle. Number the steps in the correct order.

• The Program Counter (PC) holds the address of the next instruction to be fetched. It sends this address to the Memory Address Register (MAR)

• The MAR then uses the address bus to send the address to the RAM.

• The instruction stored at that address in RAM is sent back to the Memory Data Register (MDR) via the data bus.

• The MDR then transfers the instruction to the Current Instruction Register (CIR) for execution.

• Finally, the PC is updated to point to the address of the next instruction, preparing for the next fetch cycle.

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Labelling

Identify and label the different acronyms related to the fetch stage of the fetch-decode-execute cycle.

Drag labels to their correct position on the image

Current instruction register

Memory data register

Program counter

Memory address register

Random Access Memory

Decode Stage

The decode stage is the process in which the instruction retrieved from memory is converted into a form that the CPU can understand.

Reorder

Below are the steps involved in the decode stage of the fetch-decode-execute cycle. Number the steps in the correct order.

• The decode stage begins when the Current Instruction Register (CIR) receives the instruction from the Memory Data Register (MDR).

• The Control Unit (CU), a component of the CPU, takes charge of decoding the instruction.

• The CU refers to the instruction set, which is a collection of commands that the CPU can understand and execute.

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What is a set of commands that can be processed by a certain CPU?

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What is the component in the CPU that performs all the mathematical and logical operations required when processing data and instructions?

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What is the register built into the ALU that stores the result of any temporary calculations?

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What are the wires used for the transmission of control signals between components in a computer?

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What component in the CPU is responsible for ensuring that the fetch-decode-execute cycle is performed correctly?

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Where is data stored before it is fetched into the CPU?

Multiple Choice

What is the role of a bus?

• A bus is used to power the computer's hardware.
• You can use the school bus to go to school or to do the grocery shopping.

• The role of a bus is to transfer data between components in a computer system.
• A bus connects the keyboard to the monitor.

3.5 Factors that can affect the performance of a CPU

There are three main factors that can affect the performance of a CPU and this is the number of cores it contains, the clock speed and the size of the cache.

Multiple Choice

Which three main factors affect the CPU performance?

• Power supply wattage
• Clock speed, number of cores, cache size
• Graphics card model
• RAM size

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Which three main factors affect the CPU performance?

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What is the part of the CPU that contains all the components used to perform the fetch-decode-execute cycle?

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What is the number of fetch-decode-execute cycles that can be performed in a second?

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What is clock speed measured in?

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What is a type of storage that is built into the CPU to store the most frequently used data and instructions?

Multiple Choice

Which CPU can process more instructions at the same time, a quad core or a dual core?

• A quad core can process more instructions at the same time than a dual core.
• Both quad core and dual core process the same number of instructions.
• A dual core can process more instructions than a quad core.

Multiple Choice

How many instructions per second can a dual core 2.4 Ghz CPU process?

• 4.8 billion instructions per second
• 1.2 billion instructions per second
• 2.4 million instructions per second
• 6.0 billion instructions per second

Multiple Choice

If the cache size of a CPU is too big, this can actually have a negative effect on the performance of the CPU. Why might this happen?

• A larger cache always improves CPU performance.
• A large cache can increase access times and latency, leading to worse performance.
• Big caches reduce the need for memory access.
• A large cache eliminates all latency issues.