The systems life cycle

Systems analysis

Index:

Introduction……………………………………...……….Pg.01

Stages of systems life cycle…………………………...…..Pg.02

Explanation………………...…………………………….Pg.03

Finding Out About Existing Systems……………...……Pg.04

Positives and negatives…………………………………Pg.05-6

Conclusion………………………………..……………….Pg.07

References…………………………………………………Pg.08

Introduction:

All things have a beginning, middle and an end, and information technology (IT) is no different. In the early of computing, most existing work-based system were manual. Indeed it could be argued that IT sees more rapid change than many other technologies. Think how many ‘upgrades’ have happened with your favorite software. For instance the first stage in looking at an existing system and seeing whether a new computer software system is needed for upgrade this is called feasibility study. Once this has been completed and the decision to proceed with or to abandon the examination of the system has been made, the feasibility study is finished.
This could be a system to keep track of all the students' names, addresses, telephone numbers and grades, or it could be a new system for an online bank to let customers open a new account.
No matter what the system might be, if the organization doesn't conduct a systems analysis (often known as the system life cycle); they are likely to find that their new system disappoints them and doesn't solve the original problem.

1

Stages of systems life cycle

The SLC consists of the following stages: 1. Investigation and analysis 2. Design 3. Development and testing 4. Implementation 5. Documentation 6. Evaluation
The system lifecycle is a view of a system or proposed system that addresses all phases of its existence to include system conception, design and development, production and construction, distribution, operation, maintenance and support, retirement, phase-out and disposal.
2
Explanation:

The analysis is the first stage you must tackle when developing a system.
Systems analysis involves examining the existing system in detail, when an existing system is being replaced by new systems this phase will examining the existing system in detail using some or all of interviewing users, giving questionnaires to users, observation of people using the existing system and examination of documents used in the existing system.
Sometimes it is not clear whether or not it is a good idea to create a new system to perform a job. If there is an existing system (manual or computerized) doing the same job as the new system will then it may be that a new system would offer few or no benefits over the older system. The analysis should consider whether or not to set up an INFORMATION SYSTEM.

For examples: * Collecting information on how the existing system works * Establishing its input and output and processing * Identifying the problems.

3
Finding Out About Existing Systems:

If the job that the information system will carry out is currently being performed by another system then a good starting point for a feasibility study is to examine the existing system.
Even if it has already been decided that a new system will be created it is still a good idea to examine any existing system.
Any problems with the system can be identified and new ways of performing the job can be considered. Interviews | People who operate the current system can be interviewed to find out what they think of it. Interviews can be in more depth than a questionnaire could be. If an interviewee makes a useful point about the system then the person doing the interview can follow the point up to get further information. This is not possible with a questionnaire. | Questionnaires | Questionnaires are useful when information about a system has to be gathered from a lot of people. Information can be obtained far more quickly by using questionnaires than carrying out interviews. Because people can remain anonymous they may be more likely to tell the truth than they would in an interview. | Observations | Observation of how the current system works and what each person does to use it can give an unbiased view of how the system works. Because the person designing the system is doing the observation himself it is possible to get first-hand information about how the system works. The system developer can identify if any of the workers have been lying about their role in the system. | Documentation | Manuals describing how the current system operates can be collected. Any forms used to collect information for the current system or reports produced by the current system can be looked at. |
A variety of methods can be used to identify how the existing system works. These include:

4
Advantaged and Disadvantaged:

* Looking At Existing Documentation:
Advantages
* Could Save Time As There May Be Copies Of Previous Analysis. * Can See Existing Inputs, Processing And Outputs. * Allows The Analyst To Predict The Size Of The System Needed By Looking At The Amount Of Data That It Will Be Required To Handle.
Disadvantages
* Very Time Consuming To Look Through All Of The Existing Documents. * Very Expensive As The Analyst Will Need To Be Paid For Time Spend Looking At Documentation. * Time Could Be Wasted If Existing Documentation Is Not Relevant To The New System * Questionnaire:
Advantages
* Answers Are More Honest As The Questions Can Be Answered Anonymously. * Fairly Cheap Method of Gathering Data. * Answers To The Questionnaires Can Be Analyses Automatically Using An (Optical Mark Reader).
Disadvantages
* People Do Not Complete Or Return The Questionnaire * Unclear Questions Cannot Be Explained As People Are Left To Answers The Question Alone. * You May Get Incorrect Data If People Have Misunderstood A Question. * It Is Hard To Ask Very Technical Or Specific Questions On A Questionnaire.

5 * Interviews:
Advantages
* Questions Can Be Explained If They Are Misunderstood. * More Complex Questions Can Be Asked Which Will Give More Detailed Findings. * Question Can Be Changed To Suit Who Is Being Interviewed (Different Questions For A Director Compared To A Regular Employee). * You Will Get Full Set of Data As the Person Being Interviewed Has No Choice but To Answer All the Questions.
Disadvantages
* Interviews Take Far Longer To Complete Than Questionnaires. * Expensive To Carry Out As The Person Being Interviewed Need To Be Taken Away From Their Work. * Answers May Not Be Honest As The Person Being Interviewed Cannot Remain Anonymous (They May Give Answers They Think Are Expected Rather Than The Truth). * Observations:
Advantages
* Analyst Can See Exactly What The Current System Does Well And Not So Well. * Not Expensive To Carry Out As The Employee Is Not Taken Away From Their Work.
Disadvantages
* Person Being Watched Might Feel Uncomfortable And Work In A Different Way To Usual.

6 Conclusion: Analysis is an important part of the system life cycle because with it you u can find out the pros and cons of programs and if they need any assistance in any matter, like companies that don’t have computer programs for cashiers or companies who don’t have website featuring their best assets.
Therefore system analysis main step before the new system will be develop

7
References:

http://www.epicnewmedia.co.uk/ http://www.hollyfield.kingston.sch.uk/ http://en.wikipedia.org/wiki/System_lifecycle http://www.teach-ict.com/ 8