Chapter 4 (System life cycle) Flashcards
What is system analysis?
It is the term which deals with the in depth study or analysis of systems and their daily functioning.
Who is a system analyst?
A systems analyst is a person who makes use of computers and related systems to design new IT solutions, modify, enhance or adapt existing systems and integrate new features or improvements, to improve business efficiency and productivity all together.
what are the Functions of a system analyst?
1 examine existing IT systems and business models;
2 analyses systems requirements;
3 undertake product development;
4 Implement, configure and test feasible solutions.
Why carry out Systems analysis?
1 A System is computerized and may be out of date – > it needs replacing
2 Small company has a computer system but its use if very limited + could be improved to allow many more aspects of the business to become computerized.
What is feasibility study?
It is the measure and the study of how beneficial the development of the system would be to the organization in terms of cost.
The Stages of Systems Life cycle??
The systems life cycle is so named because it is a circular process. There is no real start and finish point, because after a new system has been evaluated this leads to further improvements being needed and so the whole process starts over again.
what are the different stages of system analysis
1 Analysis 2 Design 3 Coding 4 Testing 5 Maintenance 6 Planning
The purpose of analyzing the existing system is?
1 To see how data flows around the system.
2 To see what data comes in to the company,
3 How it is processed and
4 What outputs they produce?
5 Only after this has been determined will the analyst decide on what sort of computer system should be implemented.
What is Analysis?
The analysis involves some or all of the following stages: • Fact finding – this is usually done in four ways. • Understanding the current system • Produce data flow diagrams • Identify the user requirements • Interpret the user requirements • Agree the objectives with the user • Collect data from the current system
How to Gathering / Collecting Information?
As much information about the present system needs to be gathered as possible. The system analyst can use a number of techniques that consist of mainly: 1 Questionnaires 2 Interviews 3 Observations 4 Analyzing documents
Questionnaires
They are normally preset for a large group of persons.
Mainly consists of 2 types:
Closed questions (multiple choice)
Open questions.
Advantages of using questionnaires
1 Can get answers from a lot of people in a relatively short space of time
2 They provide lots of data for analysis and the more data sets, the more accurate the analysis
3 Everyone answers the same questions i.e. same information is requested. Reduces bias.
4 Allows people to answer at a time convenient to them
5 If anonymous, perhaps more honest answers will be provided
6 Questions can be planned ahead of time by the analyst
Disadvantages of using questionnaires?
1 Only as good as the questions being asked. If the questions are poorly worded or they are biased then the data obtained might not give an accurate picture.
2 Can be difficult for the analyst to ask the right questions if they are unfamiliar with the system
3 They are impersonal, people may be more open face to face discussions
4 The response rate may be poor - especially if people are busy or don’t see the benefit in answering
5 Difficult to allow people to expand on their answers, especially with closed questions
Interviews
They are normally used for obtaining information from a group of selected individuals.
Advantages of conducting interviews
1 Excellent for personal contact and understanding with the user
2 Can elicit hard-to-quantify information and knowledge
3 Extra detail can be drawn out on the spot
4 Opinions can be aired and considered by people in the group
Disadvantages of conducting interviews
1 Take up a lot of time for both individuals and the analyst
2 Must be well structured to be efficient - it is easy to waste time in an interview
3 Only practical for a limited number of people
4 Less quantitative than a questionnaire
5 People have to be available
Observations
Observation is a process where the observer analyses the daily undertakings of organizations or people to see how tasks are completed and delivered.
Mainly two types:
1 Direct observation
2 Indirect observation
Advantages of observations
1 Useful if there are no documents involved the system
2 Can spot inefficiencies in the system
3 Can help identify persistent problems
4 Analyst can rapidly understand first-hand what the system needs to do
5 Users can impart their experience of the system directly
Disadvantages of observations
1 People don’t like being watched
2 Take up a lot of time
3 Analyst may be in the way on a busy day
4 Not so efficient at capturing quantitative data for analysis
Examining documents
In this process the analyst brings in all the relevant documents where they will be examined to determine the way they are input, manipulated, sorted and output.
Advantages of analyzing documents
1 Excellent for tracking data flow
2 Excellent for identifying data types and formats
3 Useful to identify inefficient data flows so making the new system better
Disadvantages of analyzing documents:
1 There may be other important data that are not actually in the documents
2 Cannot capture the efficiency of the process. Speed/delays etc
3 Does not help with understanding how people actually use the data
What is the design part of system life cycle?
Once the analysis has taken place and the systems analyst has some idea of the scale of the problem and what needs to be done, the next stage is to design the key parts of the recommended system. The following is a list of tasks that are usually done.
• Design the data capture forms/input forms
• Design the screen layouts
• Design output forms and reports
• Produce systems flowcharts and/or pseudocode
• Select/design any validation rules that need to be used
• Select the most appropriate data verification method(s)
• File structures/tables need to be designed/agreed
• Select/design the hardware requirements for the new system
• Select/design the software requirements
• Produce any algorithms or program flowcharts
• Design a testing strategy/plan
What is off-the-shelf software?
Off-the-shelf software, which is created for use by a large range of customers - it tends to be quite general-purpose.