The Systems Life Cycle: Analysis (Cambridge (CIE) IGCSE ICT)
Revision Note
Written by: Robert Hampton
Reviewed by: James Woodhouse
What is the system life cycle?
The system life cycle is a structured process that guides the planning, creation, testing, and deployment of an information system
Ensures systems are systematically developed, meeting needs of stakeholders, minimising risks and maximising efficiency
The first stage is analysis, the purpose is to:
Gather detailed requirements from stakeholders and analyse them to understand what the system should accomplish
Research Methods
What are research methods?
Research methods are different ways a systems analyst could analyse the current IT system in order to help understand the state of the current system
Research methods enable an analyst to identify areas for improvement
There are four main research methods:
Observation
Watching users interact with the current system to see how it acts/works
Questionnaires
A structured set of pre-determined questions to enable an analyst to get the views of the existing system from:
Workforce
Clients
Other system users
Interviews
One-to-one question and answer sessions to enable an analyst to dig deeper in to the views of existing users of the system
Looking at existing system (including paperwork)
A full look at the state of the existing system including:
Checking training manuals
How paperwork is filed
Operational instructions
Accounts etc.
Helps an analyst to identify the scale of the a problem, memory requirements and any input/output devices
Research method | Advantages | Disadvantages |
|---|---|---|
Observation |
|
|
Questionnaires |
|
|
Interviews |
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|
Looking at existing system |
|
|
Analyse Current System
How do you analyse the current system?
To fully analyse the current system , there are a number of key aspects that must be identified, these include:
Inputs: data or information entered into the system
Outputs: data or information generated by the system
Processing: tasks performed by the system on the inputs to produce the outputs
Problems: issues that users face with the current system
User requirements: what users need from the new system
Information requirements: data or information the new system must process
Data flow diagrams (DFDs) are useful for analysts to understand the inputs, outputs and processing in the existing system
A requirements specification is drawn up from the results of the analysis
How the new system will work, be deployed and a time scale
Hardware and software selection
Identify suitable hardware
Consider system requirements, compatibility, and cost
Justify choices based on user needs and system performance
Identify suitable software
Consider functionality, compatibility, and ease of use
Justify choices based on user requirements and system efficiency
Worked Example
A small company makes toys and then delivers them to shops.
Throughout the day orders are received by the company from its customers. The office workers in the finance department create and store an invoice for each order. They are too busy to be disturbed by their work.
Delivery drivers receive copies of the invoices which they will pass on to their customers. The drivers make a large number of deliveries per day and do not return to the office.
A systems analyst will research the current system and suggest improvements to be made.
For each type of employee identified above, describe the most suitable method of collecting information from them, giving a reason for your choice.
[4]
Answer
Office workers:
Observation of the processes taking place [1]
Looking at existing paperwork [1]
Reason:
One of:
Enables the systems analyst to see the whole system [1]
There are too many workers to interview them all [1]
Questionnaires/interviews would stop them from working on their tasks [1]
Can see how the files are stored/processes undertaken [1]
It allows information to be obtained that cannot be obtained in other ways [1]
enables necessary storage, and computer equipment to be identified [1]
If they are observed, then they may change the way they work [1]
They are too busy to be interviewed [1]
Delivery drivers:
Questionnaires could be handed out [1]
Reason:
One of:
They can complete them in their own time/at their leisure [1]
Questionnaires tend to be more accurate [1]
The data can be collated more quickly as everyone can complete at the [1]
same time rather than interviewing which is one after the other [1]
Individuals remain anonymous therefore they will be more truthful/reliable [1]
Easier to analyse [1]
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