Physical components that make up the computer system
Hardware
Each piece has a specific role in the computer system
Can be internal (fixed inside) or external
Input devices
Devices that inputdata into the computer system
Input devices
Mouse
Keyboard
Microphone
Barcode scanner
Output devices
Devices that output data from the computer system
Output devices
Monitor
Speakers
Printer
Projector
External storage devices
Provide externalstorage or backup solutions
To run computer, system must consist of both hardware and software
Software
Programs for controlling the operation of the computer or processing electronic data
Types of software
Application software
System software
Application software
Software with specific tasks (e.g. word processing, spreadsheets, databases, graphics editing, audio/video editing)
System software
Provides services for the computer to operate (e.g. operatingsystem, devicedrivers, utility software)
System software
Operating system
Antivirus
Performance utilities
Applets are smallcomputer programs that performspecific tasks within a largerprogram
Applets
Small computer program that performs a specific task within a larger program
Creating content for presentation
1. Use word processor to type up text
2. Use spreadsheet software to create a graph
3. Use graphic editing application to include pictures
Producing menus for a restaurant
1. Use word processing to include text and pictures
2. Use spreadsheet software to calculate the cost of meals
Control and measurement systems
Measure conditions to maintain an environment (e.g. temperature in a greenhouse)
Automatically take action to control the environment (e.g. turn on heater when temperature drops)
Analog signal
Continuous range of values collected by sensors
Digital signal
Discontinuous values converted from analogsignals, understood by computers
Analog to digital conversion
Analog signals from sensors are converted to digital signals using an analog to digital converter so computers can understand them
Measuring and control software
Measures conditions in an environment (e.g. temperature in a greenhouse)
Compares measurements to preset levels
Takes control actions (e.g. turn on heater) to maintain desired conditions
Sensors placed in a river to check waterlevel, if level rises above 5 meters a flood barrier is raised
Sensor data
Cannot be directlyread by computer, requires analog to digital converter
Measurement systems
Take readings and store results, can detect changes in the environment
Control systems
Change the environment, compare sensor values to preset levels and take action accordingly
Using computers and sensors to measure temperature has advantages over manual readings, including measurements taken outside school hours, more accurate and consistent readings, and continuousmonitoring
Devices used in control systems
Computer
Sensors
Analog to digital converter
Actuators (e.g. lights, heater, motor, pump)
Operating systems
Managecomputerfunctions including hardware devices, input/output, and provide graphical user interface
Utility software
Maintain computer resources by running specific tasks, e.g. antivirus, performance optimization
Device drivers
Allow hardware devices to run on a computer
Linkers and compilers
Translateprograms written in specific languages into executablefiles that can be run by the computer
Examples of system software
Operating systems
Utility software (e.g. antivirus, device drivers)
CPU
The brain of the computer system, where all the calculating and decision making takes place
CPU
Modern computers have dual or quad core processors which can process instructions simultaneously and independently
Allows an instruction or data to be processed, decoded and executed
Processing an instruction
1. Fetch data and instructions from main memory (RAM)
2. Decode the instruction
3. Execute the instruction
Primary storage (main memory)
Holds data, programs and instructions that are currently in use
Primary storage
Random Access Memory (RAM)
Read Only Memory (ROM)
Random Access Memory (RAM)
Temporary storage for instructions being processed by the CPU, volatile (data lost when powered off)
Read Only Memory (ROM)
Holds boot up instructions, non-volatile (data not lost when powered off)