Systems Flow Charts Learning Objective: To understand what a System Flowchart is. It helps to know that the most basic definition of a system is: a connection of parts that does something useful.
What is a system flowchart? System flowcharts are a way of displaying how data flows in a computer-controlled system, and how decisions are made to control events. There are lots of symbols used. Basic ones include:
What is a system flowchart? These - and other symbols - are used to show how data flows and how decisions are made. They are connected together to show what happens to data and where it goes. Note that system flow charts are very similar to data flow charts. Data flow charts do not include decisions, they just show the path that data takes, where it is held, processed, and then output.
Using system flowchart ideas This system flowchart is a diagram for a 'cruise control' for a car. The cruise control keeps the car at a steady speed that has been set by the driver. The flowchart shows what the outcome is if the car is going too fast or too slow. The system is designed to add fuel, or take it away and so keep the car's speed constant. The output (the car's new speed) is then fed back into the system via the speed sensor.
Mix and match activity: Create the systems flowchart for the cruise control
Your Systems Flow Chart should look like this Other examples of uses for system diagrams include:- The modeling of bank systems Aircraft control Central heating Automatic washing machines Calculators Booking systems for airlines
Input and output: For the system to work there is an input and an output. The process is taking the input and doing something with it - modifying it in some way - and producing an output. In a computer system the processing will be done by a microprocessor of some kind. Feedback is the output fed back to the input. The 'Cruise Control' flowchart is an example of negative feedback because the result is that the speed is always pushed towards the desired speed. Positive feedback would push the speed AWAY from the desired speed! Another example of feedback is in the computer control section on BBC Bitesize.
Examples of inputs and outputs Inputs can include: Typing on a keyboard Mouse Voice Scanner Camera Pressure sensor Temperature sensor Magnetic sensor Moisture sensor Light sensor Outputs can include: Printers Speakers Motors Monitors Heaters Electromagnets Bulbs/LEDs
Independent Tasks You have been given a worksheet to complete, start with the online quiz by visiting: http://www.bbc.co.uk/schools/gcsebitesize/gigaflat/ict/2systemflowchart/2systemflowchart_quiz.shtml Make a note of your score on the worksheet
Task One: List three different types of input and output device together with the other information shown. Type of Devise Advantages Disadvantages Input: Output:
Task Two: Draw a simple flow chart of milk getting from the cow to your doorstep in time for your breakfast each day.
Extension Task: In recent years there have been a number of significant changes in the ways in which data can be input into computer systems, for example the development of voice recognition software. Write a report to your Office Manage suggesting how the main method of keying in data, i.e. using a keyboard, will change in the next five years. How will the changes affect the equipment used in business? What will the effects be on office design? What will the implications be for staff training?
Glossary of Key Terms Data: Data is numbers, words or pictures without context or meaning. Flowchart: An illustration showing how a system will work. Hardware: Machinery and equipment such as the monitor, the mouse, the processor, floppy disks etc. Sensor: Sensors are used to measure physical quantities such as temperature, light, pressure, sound, and humidity. They send signals to the processor.