1. Components of an Information System By Ciaran Gallagher Covered in this presentation: Input, Processing, Output, Storage and Feedback… Covered in this presentation: Input, Processing, Output, Storage and Feedback…

2. Introduction An information system is a set of things working together, to process and derive information. For example, a car can be classed as a system because it consists of many component part working together. A school could also be classed as a system since it consists of many component parts such as teachers, students, caretakers and equipment all working together.

3. The function of an information system Feedback InputProcessing Storage Output

4. Explanation of Diagram All information systems receive data. This is input. Then, some operation is performed using this data. This is processing. Some consequence results from this processing. This is output In some systems, the output can be re-used as input, a process known as feedback. Computer systems may also require storage to store data temporarily for processing and to preserve data permanently for future use. (eg. hard-disk)

5. …More about Feedback Feedback is the use of a systems output as a further input. (It is re-used) This is a common feature of a control system. Example: Cruise Control in a car Systems that regulate the temperature in a car

6. Closed-Loop Feedback Used in systems that require no user intervention once the system is operative. That is, once it is installed the system will look after itself until it is de-activatedExample: A greenhouse that maintains temperature and humidity levels without intervention.

8. Open-loop feedback Used in systems that do require human intervention after the output has been generated. Example: The system will take no further action until intervention is received. Example: A fire alarm is set off. It keeps sounding until it is reset. A game of chess on a computer. When playing against the computer, when it is the users turn, the computer will take no action until it receives the users intervention.

10. Open-loopClosed-loop Open-loop or Closed-loop? A Thermostat? (Temperature is set, temperature is maintained…) An Alarm Clock? (Once triggered, will keep sounding) Closed-loop Temperature will remain constant until de-activated! Open-Loop Once triggered, will continue to sound until human intervenes!

11. Homework………………………… Pg 25 of textbook Qs 1-5 1.Define an information system (3) 2.What is feedback? (2) 3.Using a diagram, illustrate the relationship between input, output, processing, output and feedback. 4.Describe, using an example, open-loop feedback. 5.Describe, using an example closed-loop feedback.