Grade 8

Grade 8: Lesson 3- Central Processing Unit (CPU) and Unit of Storage 2023

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Central Processing Unit (CPU)

Watch the video below

Answer the following questions

  1. What does CPU mean?
  2. What is another name for the CPU?
  3. What are the three components of the CPU?
  4. List three examples of Storage devices.
  5. What are the three main activities of the computer system?
  6. What are some important parts of the CPU cabinet?

The CPU is the computer hardware component that’s responsible for interpreting and executing most of the commands from the computer’s other hardware and software. It is used to manipulate data-is responsible for carrying out arithmetic and logic functions. It is seen as the brain of the computer.

Image result for cpu

Some devices that use a CPU include desktop, laptop, and tablet computers and smartphones.

CPU’s come in a variety of speeds which are known as ‘clock rates’. Clock rates are measured in ‘Hertz’. Generally, the faster the clock rate, the faster the performance of the computer.

Intel and AMD are the two most popular CPU manufacturers for desktops, laptops, and servers, while Apple, NVIDIA and Qualcomm are big smartphone and tablet CPU makers.

Components of a CPU

The TWO MAIN components of a CPU include the following:

  • The arithmetic logic unit (ALU), which performs arithmetic and logical operations.
  • The control unit (CU), which extracts instructions from memory and decodes and executes them, calling on the ALU when necessary. the control unit directs and coordinates the activities of the CPU. The CU controls the Machine cycle.
Computer machine cycle


The computer can only do one thing at a time. Each action must be broken down into the most basic steps. One round of steps from getting an instruction back to getting the next instruction is called the Machine Cycle.

Four steps of Machine cycle

  1. Fetch – Retrieve an instruction from the memory.
  2. Decode – Translate the retrieved instruction into a series of computer commands.
  3. Execute – Execute the computer commands.
  4. Store – Send and write the results back in memory.
Image result for machine cycle

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Unit of Storage

Memory is made up of bistable devices. Bistable means the components that make up memory can be set to one of two states either on or off. These two states are represented using binary digits- 0 for off and 1 for on. As such, the smallest unit of storage of memory is called a binary digit (bit). The amount of data and instructions that can be stored in primary storage or secondary storage media is measured in bytes.

Byte – A byte is made up of a combination of 8 bits and has the capacity to represent one character i.e. a letter, a number, a symbol, a punctuation mark or a blank space.

Nibble – A nibble is made up of a combination of 4 bits.

Word – A word is the amount of bits the computer can process in one operation.

Word size – A word size or word length is the number of bits in a word. For example 32 bits and 64 bits

unit-of-storage

Home work

  • What is the difference between primary and secondary storage?
  • Describe the different storage media and their uses

Reference

https://www.lifewire.com/what-is-a-cpu-2618150

http://www.ictlounge.com/html/computercomponents.htm

http://www.wisegeek.org/what-are-the-components-of-a-cpu.htm

http://www.computerhope.com/jargon/m/machcycl.htm

http://www.jegsworks.com/lessons/computerbasics/lesson4/lesson4-3.htm#system

-http://www.jegsworks.com/lessons/computerbasics/lesson4/machinecycle.gif

http://www.proprofs.com/quiz-school/story.php?title=NTkyNzU3

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