The IPO Model

Input – Process - Output

I = Input

Input is something from the external environment that is fed into the system.

In an information system, the inputs may be raw data "captured" in some way or pre-existing data which has been provided by an external system.

In either case, the data input is provided by an external entity.

P = Process The transformation process is the most

important element of a system.

The process accepts the inputs into the system and performs some type of operation on it which transforms it into some other state. In the simplest of terms, the process is at the heart of any system.

In a computerised information system, the process is normally the storage, retrieval and modification of data which is accomplished by hardware and software.

O = Output

Output from the system which is the result of processing the input.

Without output, a system has no link back into it's external environment.

Output of an information system may be reports generated by an information system, or a picture on a computer monitor, or even data that is fed into another external system.

The IPO Model

INPUTData and Processing

OUTPUT

Your analysis starts here

The requirements of the Output, more than anything else, will determine the requirements of the System.

Steps to complete an IPO Model

Steps1. Read and understand the problem2. Identify the outputs

Pick intrinsic variable names that represent the output

3. Decide what data (the inputs) is required in order to get the required output

Sometimes these will be given to you, sometimes not, which means you may need to invent inputs.

4. Once you have the outputs and the inputs you need to determine how the inputs can be transformed into the required outputs. This is a dynamic process which may mean you need to continually return to the previous steps.

Example

Analysis for CelsiusToFahrenheit Program:

Input degrees Celsius

ProcessF = C * 9/5 + 32

Output degrees Fahrenheit

What output/s are require?

Problem Statement

A student's final grade for a course is a weighted average of two tests, a final exam, and four projects. Each test is worth 15%, the final is worth 30%, and the projects are worth a total of 40% (10% each). Given a student's grades for all of these assignments, calculate the final score.

What input/s are required?

Problem Statement

A student's final grade for a course is a weighted average of two tests, a final exam, and four projects. Each test is worth 15%, the final is worth 30%, and the projects are worth a total of 40% (10% each). Given a student's grades for all of these assignments, calculate the final score.

What process/es are required?

Problem Statement

A student's final grade for a course is a weighted average of two tests, a final exam, and four projects. Each test is worth 15%, the final is worth 30%, and the projects are worth a total of 40% (10% each). Given a student's grades for all of these assignments, calculate the final score.

Problem Statement A student's final grade for a course is a weighted average of two tests, a final exam, and four projects. Each test is worth 15%, the final is worth 30%, and the projects are worth a total of 40% (10% each). Given a student's grades for all of these assignments, calculate the final score.

Input Process OutputGet Result of Test1Get Result of Test2Get Result of FinalExamGet Result of Project1Get Result of Project2Get Result of Project3Get Result of Project4

1. Calculate FinalScore2. FinalScore = (Test1 +

Test2) * 15/100 + Test3 * 30/100 + (Project1 + Project2 + Project3 + Project4) * 40/100

FinalScore

Self-Check1. Consider a student file that contains the following data fields:

First Name Last Name Course Grade

Would this set of data be suitable and sufficient to use to test each of the following programs? Explain why or why not.

A program that prints a list of SDD students A program that prints a list of students nearly failing - those with a grade is less

than 50% A program that prints a list of student on the Principal’s list A program that prints a list of students from Parramatta A program that prints a list of female students.

2. Construct an IPO chart for a program that gives an employee $50 bonus for every 500 items sold in a week.

3. Construct an IPO chart for a program that will output a student's grading based on letter grades (A, B, C, D, or F) in five courses.

4. IPO ExamplesInput Processing Output

original number 1. calculate the squared value by multiplying the original number by itself

2. display the squared value

squared value

Input Processing Output

state1 salesstate2 salescommission rate

1. enter state1 sales, state2 sales, and commission rate2. calculate the total commission by adding the state1 sales to the state2

sales, and then multiplying the result by the commission rate3. display the total commission

commission

Describe what these two IPO models are doing…