MELJUN CORTES IPO & Context Diagram

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INPUT-PROCESS-OUTPUT

(IPO CHART)

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What is it?

The IPO diagram is a visual representation of a process or activity.

It lists input variables and output characteristics.

Why use it?

IPO diagram is useful in defining a process and recognizing the input variables and responses/ outputs.

When to use it?

Understand what inputs are needed to achieve each specific output.

Definition of terms

INPUT is the data flowing into the system from outside.

PROCESSING is the action of manipulating the input into a more useful form.

OUTPUT is the information flowing out of the system.

FEEDBACK occurs when the outcome has an influence on the input.

INPUT: The teacher takes register to see who is not in today.

PROCESSING: The data is loaded into the school database and processed to create attendance record of each pupil.

OUTPUT: Print out of a student who has been absent.

FEEDBACK: The teachers needs to find out why the student has been absent and the reason recorded in the input once more.It will also hopefully cause the pupil to have better attendance record.

Some Examples (Attendance system in school)

Some Examples [cont.]

Album titleArtist nameArtist ID

Query report

Display orprint lists ofalbumsproduced by particularartists

A persontypes datainto adatabase system by means of akeyboard

The keystrokes being entered by the typist is converted into ASCII format that the computer can understand.

The keystrokes being entered are immediately shown on the typist’s monitor so she can see what is being entered.

Some Examples [cont.]

Client

Design

Material

Adhesives

Tools

Workers

Finished product

Pay Workers

Happy customer

Making

Check qualitySet tools

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Context Diagram & IPO Diagram

Context DiagramIs the highest level view of a system, similar to Block

Diagram, showing a, possibly software-based, system as a whole and its inputs and outputs from/to external factors.

Shows the entire system as a single process. Interactions with users and other external entities are shown as dataflow.

They do not show the major functional processes but are particularly useful for agreeing the system boundary.

Documents the system’s boundaries by highlighting its sources and destinations. Documenting the system’s boundaries by drawing a context diagram helps the analyst, the user, and the responsible managers visualize alternative high-level logical system designs.

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Purpose of Context Diagram

1. It clarifies to the user audience the analyst's understanding

of the scope of the proposed system, the kinds of users the

system will have, and the data coming out from and going

into the system. A surprising number of misunderstandings

are exposed at this early stage.

2. It motivates and establishes a framework for the more

complicated next level (below).

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How are Context Diagram Drawn

Context diagrams are typically drawn using labeled boxes to represent each of the external entities and another labeled box to represent the system being developed. The relationship is drawn as a line between the entities and the system being developed. The relationships are labeled with a subject-verb-object format.

Context diagrams can also use many different drawing types to represent external entities. They can use oval, stick figures, pictures, clip art or any other representation to convey meaning. Decision trees and data storage are represented in system flow diagrams.

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Symbols Used on Diagrams

•processes are shown as squares with rounded corners

Process Inquiries

•external entities (the people with whom the process interacts)

External Entities

•Relationship or what we call data flows- it shows the relationship between external entities and the process.

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How are Context Diagram Drawn

When drawing a context diagram, you:

Firstly, draw and name a single process box that represents the entire

system.

Next, identify and add the external entities that communicate directly with

the process box. Do this by considering origin and destination of the

resource flows and data flows.

Finally, add the resource flows and data flows to the diagram.

Note: In drawing the context diagram you should only be concerned with the most important

information flows. These will be concerned with issues such as: how orders are received and checked,

with providing good customer service and with the paying of invoices. Remember that no business

process diagram is the definitive solution - there is no absolute right or wrong.

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SUPPLIER CUSTOMER

0--------------------

---------SALES

PROCESS

Goods Ord

ers

Promotion, visits

,

deliveries

‘terminator’ for input/output flows

Process

flow of inputs and outputs to and

from processes O

rders

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ACCOUNTING

WAREHOUSECUSTOMER

0

Order System

Order

Payment

In- StockRequest

StatusMessage

Invoice Shipping Confirmation

Shipping Order

Inventory Reports

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Employee

Accounting Departmen

t

0

Payroll System

Payroll Check

Time Sheet

Tax FormPayroll Report

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Book Supplie

r

Library System

0

Borrower

Book

Book Details

Order

Book

Book Request

Availability & Advice

Reservation

Inquiry

Borrower Number

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Technology

MELJUN CORTES IPO & Context Diagram