System Lifecycle Quiz

System LifecycleAll things have a beginning, middle and end. Information Technology is no different. IT sees more rapid change that many other technologies. Think about how many “upgrades” have happened with your favourite software.

Change has to be managed to avoid disruption, chaos and inefficiency.

This is where the System Lifecycle comes in.

Why build new IT systems?

Lots of failures, so a model has been developed and refined over the years to try and maximise the chance of s successful project. This method/mode is called the Systems Life Cycle.

Analysis

Design

Implementation

Testing

Installation

Maintenance

System Development Cycle

AnalysisInvestigate current system, determine organisations requirements for new system.

1. How does the current system operate

2. What does the current system not do

3. What should the new system be able to do

4. What are some alternative solutions

5. A recommended course of action

Project Plan•The project managers responsibility will

be to ensure the project is completed and that all deadlines are met during the various stages.

•GANTT Chart – provides a high level overview of the project schedule – showing each individual task, starting and finishing time and who will be responsible for the task.

Create your own Gantt chart•Write down the steps involved in making a

cup of tea.

•What tasks can be done at the same time?

•Covert these steps into a Gantt chart, showing each task, the time taken to complete and who will be taking responsibility for each task.

Gantt Charts1. State four key features of a Gantt chart

(4 marks)2. Explain three advantages of using a

Gantt chart for the management of a project (3 marks)

3. Construct a Gantt chart using the table below (4 marks) Milestones (Key event of the development process must be indicated on the chart

Initial task starts from 31st JanuaryDuration Task Responsibility2 days Interview key staff

membersRyan/Phil

3 days Carry out survey Alessio1 day Analysis of survey Mike5 days Observe users with

current systemJordon

5 days Produce feasibility report

Daniel

2 weeks Create design solution for possible new system

Sam

1 day Feedback on recommended solutions

Daniel

PERT charts (Program Evaluation & Review Technique)

• A PERT chart presents a graphic illustration of a project as a network diagram . It shows the relationships and dependences between each task in the schedule (easier to see which tasks can be worked on simultaneously).

• Keywords:▫Nodes; connection between each task▫Activity-on-arrow; Task▫Dummy activity (dotted line); bringing two tasks together▫Critical Path; used to determine longest route of the

project

DesignHaving identified the best solution produce a detailed design specification

Input

Output

Data Storage

User Interface

Back up procedures

Security Procedures

Test Plan

Design StageThe analysis is used to create a solution that fulfils the requirements identified at stage 1.

•Data Flow Diagrams•Entity Relationship Diagrams

Data Flow Diagrams•One way of documenting how data flows

through an organisation is to use a data flow diagram. These diagrams show where the data comes from, what processing takes place, where the data is stored and who receives the output from the system.

•A customer orders some CDs from an online store. The order is entered into the sales order processing system. The price of the CD is looked up from a file of stock items, and an invoice is printed to be sent to the customer with the CD. Details of the sale are stored on the Sales file.

• A customer orders some CDs from an online store. All customers are given 30 days credit. The customer is looked up on the customer file and if they are a new customer, their details are stored.

• The order is entered into the sales order processing system. The price of the CD is looked up from a file of stock items, and an invoice is printed to be sent to the customer with the CD. Details of the sales are stored on the Sales file.

• At the end of each month the Accounts department prints statements to send to all customers. A report of overdue accounts is kept in the Accounts department.

Implementation – Development model•Agile method?

or•Waterfall method?

State at least three advantages and disadvantages of each model.

Waterfall Strengths Agile Strengths

Breaks project into stages More interaction with clientsGood for producing a project plan

No rigid plan

Problems identified and fixed at an early stage

Software developed more quickly

Encourages correct documentation

Better response to client demandsEncourages teamworkResponsive to client

Waterfall Weaknesses Agile Weaknesses

Implies stages that may not exist Lack of structureAssumes that one stage follows another

Only works with expert developers

Does not model parallel development of modules

Needs frequent meetings

Insufficient documentationDeliverables not specified exactlyCan be inefficient – code can often be re-writtenCan lead to poor qualityConcentrates on functionality, less on usability

The heartbeat of Agile development is the iteration – the ability of the team to create working, tested, value delivered code in a short time box – with the goal of producing an increment of potentially shippable code at the end of each iteration. This is a significant challenge for the team, and mastering this skill takes guidance and practice. In agile software development, an iteration is a

single development cycle, usually measured as one week or two weeks. An iteration may also be defined as the elapsed time between iteration planning sessions. While the adjective iterative can be used to describe any repetitive process, it is often applied to any heuristic planning and development process where a desired outcome, like a software application, is created in small sections. These sections are iterations. Each iteration is reviewed and critiqued by the software team and potential end-users; insights gained from the critique of an iteration are used to determine the next step in development. Data models or sequence diagrams, which are often used to map out iterations, keep track of what has been tried, approved, or discarded -- and eventually serve as a kind of blueprint for the final product. In general, an iteration is the act of repeating.

Implementation – Alpha Testing•Alpha testing takes place during the

implementation stage, as the development is coming to an end.

•At this stage there are potentially still several issues of bug/errors in the coding, so Alpha testing is carried out internally – usually by software testers, NOT the actual end users.

Testing – Beta Testing•In software development, a beta test is

the second phase of software testing in which a sampling of the intended audience tries the product out.

•Aim – to detect any remaining bugs whilst using the software under “real” conditions.

Legacy System

•Define the term Legacy System (2marks)

•Identify two reasons why organisations continue to use Legacy systems (2 marks).

•Distinguish between an end-user and a client (2marks)