4.3.9 System Development Life Cycle (SDLC) Flashcards
In INVESTIGATION of existing system what things are investigated?
-User requirements should be identified (Aims and Objectives)
-Definition of the scope of the present system (outline current system)
e.g •Organisational chart
•Define sources of data
•Method of data capture
- Major data processing functions and processes (data flow)
e. g •High level (contextual view) data flow
-Identification of problems with the current system
-Details of existing software and hardware
e.g •Do they have equipment to implement
•Do they have in-house technical expertise
•Are there compatibility issues with existing systems
Discuss questionnaires as a method of investigation stating the pros and cons
QUESTIONNAIRES Given out to gather information for the company For; Users Managers Customers
Pros:
- Analysts don’t waste time with face to face convos, they can stick to the important points without digressing/
- Economical to reproduce and distribute
- The questionnaires can be done without the analyst being there and workers can take their time over answers
Cons:
- Response rate from posted surveys is often poor
- Respondent may misunderstand the meaning of questions and give misleading answers
- People forget to fill them in and hence an incomplete picture.
Discuss Interviews as a method of investigation stating the pros and cons
INTERVIEWS
about the current system
With; Users, Workers, Managers and Customers
Pros:
- Reveal how the departments work overall
- Identify current problems
- Individuals may supply extra information not thought of before
Cons:
- Very time consuming as a lot of people need to be contacted
- Needs skilled interviewers to get the correct information out of people
- Need to have different levels of questions for different people.
Discuss Inspecting Records as a method of investigation stating the pros and cons
INSPECTING RECORDS
(studying the paper based information produced by the company at the moment)
Pros:
To see what information is held at present and how
-To see how communications between different departments takes place now
-To identify any problems or faults in procedures
Discuss Observations as a method of investigation stating the pros and cons
OBSERVATIONS
of how the current system operates
Pros:
- To understand what they do
- Detail flow of information
- You can see time delays. Crashes or interruptions with the current system
Cons:
-Can be time consuming and span over several weeks before you can see everything
what is a feasibility report?
A summary of an initial investigation to look at the likelihood of being able to create a new system with stated aims and objectives
what does a feasibility report include?
- User requirements
- Details of existing hardware and software
- Scope of the present system (what does it do)
- Major data processing functions and processes (DFD diagrams)
- Identifying major problems with the present system (why do they need a new system)
- Cost and benefits of the new system
What do analyst do to analyse a system?
Uses DFD’s, flowcharts, data dictionaries, ER models (one-to-many, many-to-any).
what are the feactures or processes that should be considered when designing a new computer system?
- Creating the design specification for software
- Design of input methods. This will include the design of forms (data capture / on-screen / switchboard) used to input data
- Design of processes – queries, macros, calculations
- Design of output - reports / specialist documents such as invoices, payslips, etc.
- Design of data and file structures that will allow a useable system to be built. This will include the design of fields and table structure for a relational database.
- Design of information systems that will allow users to get relevant information out of the system, which will allow them to make appropriate decisions. (DFD’s / ERD’s)
- Design of networks and transmission issues such as topology, type of cable, protocols, etc.
- Personnel issues. Staff will need training and departments reorganising, skill level of the user
- Security processes and procedures i.e. registering with the Information Commissioner, where data is stored, access levels, design of backup procedures, etc.
- Design of House style/ethos
what does Implementation include?
- Acquiring and installing hardware and software
- Modifying existing software
- Producing programming code
- nstalling software in hardware
- Producing databases
- Training of users.
what does testing involve ?
There is a large team building a new system. Everyone is responsible for a certain part and they will have to test it to make sure it works.
Testing Involves:
•Detailed level testing (individuals testing their own part)
•High level testing (when all the parts are joined together)
•Systems level testing (testing the whole system)
•Testing each field (with correct, erroneous and extreme data)
•Real-life testing with real-life data
explain what is meant by direct changeover and state the adv and dis
Stop using the system one day and start using the new system the next day
ADV:
-Requires fewer resources (people, money, equipment) and is simple, provided nothing goes wrong
DIS:
- Element of risk particularly if the hardware and software are cutting edge
- If the system fails then it can be disastrous to the business
explain what is meant by parallel changeover and state the adv and dis
Old ICT system is run alongside the new ICT for a period of time until all the people involved with the new are happy it is working correctly
ADV:
- Used to minimise the risk in introducing a new ICT system
- Can compare results and be sure it is working properly
DIS:
-lots of unnecessary work (as the work is being done twice) and is therefore expensive in people’s time/work/equipment.
explain what is meant by phased conversion and state the adv and dis
A module at a time can be converted to the new system until the whole system is transferred
ADV: -Staff can deal with problems on one module before moving onto new modules
DIS:
-Only suitable for systems consisting of separate modules
explain what is meant by pilot conversion and state the adv and dis
Ideal for large organisations that have lots of locations or braches where the new system can be used by one branch and then transferred to other branches over time
ADV:
-Implementation is on a much smaller and manageable scale
DIS:
-takes longer to implement the system in all the branches
