Grade 8 Term 1

Topic: Computer Input and Out



Input:              Any data or instructions that are entered into the memory of the computer

Input Device:  Any hardware component that allows users to enter data or instructions into a computer.

Types of Input Devices

  • Keyboard
  • Mouse
  • Trackball
  • Game device
  • Touch screen
  • Glide pad
  • Pen input
  • digitizers
Types of Keyboards
Standard keyboards such as the 104-key Windows keyboards include alphabetic characters, punctuation symbols, numbers, and a variety of function key
Specialized keyboards

Source Data Automation        the process of collecting data at their point of origin in a digital form. The first goal of data automation is to avoid mistakes in data entry by making the initial entering of the data as automatic as possible
Examples of Data Automation

  • Scanner
  • Optical Character Recognition
  • Optical mark reader
  • Microphone
  • Digital Camera
  • Point of sale Terminal


Output:            is data that has been processed into a useful form

Output Device:           Hardware component that conveys information to one or more people.

Types of Output Devices

  • Printer
  • Monitor
  • Plotter
  • Speaker


There are four categories of output:
  • Text- e.g.: letters, reports, announcements, press releases
  • Graphics- e.g.: charts, drawings, clipart, photographs
  • Audio
  • Video

Multimedia      this is output made up of picture, sound and video.

Resolution       this describes the sharpness or clearness of an image.

Pixel                A pixel is the smallest element in an electronic image.

Display Device:           A display device is an output device that conveys text, graphics, and video information. Information in a display device is called soft copy.


Two types of Display devices are:
  • CRT Monitor
  • Flat panel display

Types of screens
  • Monochrome – one color for text on a single color background.
  • Color
  • CRT
  • Plasma

Printer:            A printer is an output device that produces text and graphics on physical medium such as paper or transparency film. Printed information is called hard copy. For a test print of a newly created document, you should use draft quality print.

Two categories of printers are:

  • Impact printers
    • Dot-matrix
    • Line printers

  • Non-Impact printers
    • Ink jet printers
    • Photo printers
    • Laser jet printers


The speed of a printer is measured in:
cps – characters per seconds
lpm – lines per minutes
ppm – pages per minutes



 Quiz 1 - Input 


Which of the following list of devices are used for input?


Card Reader


Game Controller


Keyboard

Joystick



Mouse

Microphone


Scanner

Webcam


Speaker

Printer


earphones

Monitor


Plotter



  1. What is Input?
  2. List two[2] devices used for video input.
  3. List two[2] devices used for sound input.
  4. List two devices used for data automation.
  5. What is the first goal of data automation?
  6. State two types of keys found on a standard keyboard.

Quiz 1 - Output

    1. What is output?
    2. What is an output device?
    3. What are the four (4) categories of output?
    4. State three (3) examples of text.
    5. What is a display device?
    6. list two types of display devices.

Topic: The Processor

The processor is the part of the computer that reads, interprets and executes program instructions.

The microcomputer uses a single processor called a microprocessor or CPU.

The microprocessor brought the following benefits to the computing world:
·                     Smaller computer
·                     less expensive computers
·                     computers that are more powerful and generate less heat
·                     computers with faster speed
·                     computers with a higher reliability

The Central Processing Unit (CPU) commonly referred to as the “brain” of the computer is the seat of the entire computer’s action.

The main functions of the CPU:

·                     Fetch data and instructions from memory
·                     Coordinating and performing instructions received
·                     Sending results of execution to memory

The main components of the CPU:

·                     The Arithmetic and Logic Unit (ALU)
·                     The Control Unit (CU)
·                     The CPU clock
·                     Registers and Buses

The Machine Cycle:


Control Unit (CU)


The control unit is the circuitry that controls the flow of information through the processor, and coordinates the activities of the other units within it. In a way, it is the "brain within the brain", as it controls what happens inside the processor, which in turn controls the rest of the PC.

Arithmetic and Logic Unit (CU)

This is a twin unit that performs all arithmetic calculations (Arithmetic unit) and logical operations (Logic unit) on data being processed.

CPU clock
The CPU clock regulates the speed of the processor and it synchronizes all the parts of the PC. The speed of the processor is measured in Mega Hertz (MHz) which means millions of machine cycles per second.

Registers
Registers are high speed storage areas in CPU that temporarily holds data and instruction.

Bus

The electrical paths or channel along where bits are transferred.



Quiz 

Answer the questions below

  1. What name is given to the part of the computer that reads, interprets, and executes program instructions?
___________________________________________________________________

  1. State five (5) benefits of the microprocessor to the computing world
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________

  1. What does CPU stand for?
_____________________________________________________________________

  1. State three (3) other names given to the CPU.
_____________________________________________________________________
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  1. State the three (3) main functions of the CPU.
_____________________________________________________________________
_____________________________________________________________________
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  1. The speed of the computer is measured in what units?

_____________________________________________________________________

Which components of the CPU is being described below

  1. Decode all instructions given to the computer.
_____________________________________________________________________


  1. Performs all calculations on data being processed.
_____________________________________________________________________

  1. Regulates the speed of the processor and it synchronizes all the parts of the PC.
_____________________________________________________________________

  1. High speed storage areas in CPU that temporarily holds data and instruction.
_____________________________________________________________________

  1. The electrical paths or channel along where bits are transferred.
_____________________________________________________________________

Draw and label the machine cycle below using the words provided.



  1. Decode
  2. Fetch
  3. Store
  4. Execute
  5. Main Memory
  6. Control Unit
  7. ALU
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