Hardware - IGCSE

Hardware

• What is a hardware

• List examples of hardware

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​Hardware

Word Cloud

What is a hardware

Word Cloud

Give one example of a hardware device

Multiple Choice

What hardware component is often referred to as the "brain" of the computer?

• CPU
• RAM
• GPU
• Hard Drive

The Central Processing Unit

• A component in a computer system that processes data and instructions. CPU is a brain of a computer.

• CPU Consists of

  • control unit (CU)

  • arithmetic and logic unit (ALU)

  • registers and buses.

• Microprocessor: An integrated circuit that is able to perform many of the functions of a CPU

Control Unit

• The control unit reads an instruction from memory. It controls all the operations in the CPU.

• Program Counter (PC): A component in the CPU that stores the address of the next instruction to be processed.

• Address: A memory location in the RAM.

• system clock: Is used to produce timing signals on the control bus to ensure this vital synchronisation takes place – without the clock the computer would simply crash!

Arithmetic and Logic Unit (ALU)

• The component in the CPU that performs all the mathematical and logical operations required when processing data and instructions.

• Mathematical operations: +, -, *, /, left or right logical shift

• Logical operations: AND, OR, NOT

Registers

• Register – a temporary component in the CPU which can be general or specific in its use; it holds data or instructions

• Examples of specific registers.

  • Current instruction register (CIR): this register stores the current instruction being decoded and executed

  • Accumulator (ACC): this register is used when carrying out ALU calculations; it stores data temporarily during the calculations

  • Memory address register (MAR): this register stores the address of the memory location currently being read from or written to

Special Purpose Registers

• Current instruction register (CIR): this register stores the current instruction being decoded and executed

• Accumulator (ACC): this register is used when carrying out ALU calculations; it stores data temporarily during the calculations

• Memory address register (MAR): this register stores the address of the memory location currently being read from or written to.

• Memory data/ buffer register (MDR): this register stores data which has just been read from memory or data which is about to be written to memory

• Program counter (PC): this register stores the address where the next instruction to be read can be found

Homework

1. Draw the digram for the Von Neumann Architecture

2. What is an embeded system?

3. Give three examples of an embeded system

Multiple Choice

What does ALU stand for?

• Arithmetic Logic Unit Test
• Analog Logic Unit
• Arithmetic Linear Unit
• Arithmetic Logic Unit

Multiple Choice

The ALU is primarily responsible for:

• Performing arithmetic and logical operations.
• Controlling the flow of electricity.
• Managing input and output devices.
• Storing data in memory.

Multiple Choice

Which of the following is NOT a basic operation performed by the ALU?

• Subtraction
• Multiplication
• Addition
• Data storage

Multiple Choice

The Program Counter (PC) always contains the address of the instruction currently being executed.

• TRUE

• FALSE

Multiple Choice

The Instruction Register (IR) holds instructions for future execution

• TRUE

• FALSE

Multiple Choice

The Memory Address Register (MAR) can hold both memory addresses and data.

• TRUE

• FALSE

Multiple Choice

The contents of the Program Counter are automatically incremented after each instruction fetch.

• TRUE

• FALSE

Multiple Choice

The Memory Data Register (MDR) must hold data before it can be written to memory.

• TRUE

• FALSE

Multiple Choice

The Memory Address Register (MAR) and Memory Data Register (MDR) are used in every memory access.

• TRUE

• FALSE

Fetch, decode and execute cycle

• To carry out a set of instructions, the CPU first of all fetches some data and instructions from memory and stores them in suitable registers. Both the address bus and data bus are used in this process. Once this is done, each instruction needs to be decoded before finally being executed.

​Fetch, Decode and Execute Cycle

Pair Work (10 Mins)

1. Where is data stored before it being fetched into the CPU?

2. Which component of the CPU is responsible for making sure the fetch-decode-execute cycle is performed correctly?

3. What is a role of a bus?

4. Why does the ALU need the ACC, what would have to happen if it didn't have this special register?

Factors that can affect the performance a CPU

• The performance of a CPU refers to how quickly the CPU can process an instruction.

• The more instructions that can be processed in a second, the higher the performance of the CPU.

Multiple Choice

People often want a .................. performing CPU, so they are not sat waiting and frustrated with their computer because it takes long time to open a document.

• slower
• cheaper
• larger
• high

1. Number of Cores

• If a CPU has one core, it can perform one fetch-decode-execute cycle.

• If a CPU has two cores (dual core), It can perform two fetch-decode-execute cycle.

• Therefore, If a CPU has multiple cores, its performance can be increased

2. Clock Speed

• A CPU contains an internal clock that controls the speed at which instructions are processed.

• The speed is measured in Hertz.

• If your CPU had a clock speed of 1 hertz is able to process one instruction per second.

• Most modern computers have a clock speed that is measured in gigahertz (GHz).

• A CPU with a clock speed of 2GHz can process 2 billion instructions a second

3. Size of the Cache

• A type of storage that is built into the CPU, to store the most frequently used data and instructions.

Pair Work

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

2. How many instructions per second can a dual core 2.4GHz CPU process?

3. 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?

Homework

• May/June 2024 Paper 12 Question number 5.