Systems Analysis and Design SLDC Phase Activities! Systems Analysis and Design Part 3

Systems Analysis Phases This WEEK we will.. Examine the SDLC phases in more detail

Systems Life Cycle Phases 1 Initiation & Planning Phase problem is defined feasibility study is carried out project schedule is defined project team is assembled 2 Investigation – information is gathered interviews conducted questionnaires produced research carried out experts consulted 3 Analysis of requirements – system requirements defined prototypes may be built. 4 Design alternative solutions are identified hardware and software are chosen System specification is developed 5 Implementation – data is converted software constructed the system is installed 6 Testing – unit & integration testing system load testing acceptance tests 7 Support & Maintenance system is tested and verified, errors corrected training and support may be required to end users

1 Initiation/Planning Phase - A Problem Domain How do systems analysts start the analysis process? The demand for a new system will have been triggered by some problem with the old system The types of problems the current system may have are C P E E I s Control Problem Information may be available to the wrong people. Users may not be able to act on information appropriately Economic Problem The system is costing too much Performance Problem The system does not respond quickly enough. Task takes too long to complete. Efficiency Problem Collecting, processing and distributing information may be using too many resources Information Problem Acquiring information at the right time is a problem for the users. Service Problem The system may be too difficult to use

1 Initiation/Planning Phase - Problem Statement A problem statement is a sentence that identifies what needs to be fixed, changed or improved. Here are some examples At a local garden centre, the price tags frequently fall off the items. This means that customers must wait while the item price is checked. At a college, the registers are kept in filing cabinets. The registers frequently go missing. Also, tutors are slow to complete the ‘withdrawal from course’ forms for frequently absent students.

1 Initiation/Planning Phase - Feasibility Study Once the problem has been identified, a feasibility study should carried out to compare the costs and benefits (social & economic) of the current system with the expected costs and benefits of the new one. 'Feasibility Report' The report should include a description of the existing system, how the new system will improve on it, or if the project should terminate. The following aspects should be examined Technical feasibility Economic feasibility Legal feasibility Operational feasibility Schedule feasibility

1 Initiation/Planning Phase - Feasibility Study Technical feasibility - do we have the technology to create such a system? Economic feasibility - is the proposed system is cost-effective or not. Legal feasibility - is the proposed system legal? Operational feasibility - how will the new system affect the working lives of the employees? Are current work practices adequate to support the new system or are changes needed? Schedule feasibility - How long will it take to get the system in place. Is this time-frame acceptable?

TASK 1 – Initiation/Planning Phase… Draw or find at least three pictures you think illustrate this phase, (think about the activities of this phase) Here is my example

2 Investigation Phase - Collect Information After accepting the feasibility report, a detailed study is conducted. The purpose is to fully understand the existing system by collecting information and attempting to identify the basic information requirements. The Systems Analyst will investigate and report on the following: Scope (objectives & system boundaries). Input (data capture & composition). Files (master file storage & access). Processing Tasks (all the necessary procedures). Output (style & content of system outputs). Controls (system accuracy, integrity & security). Management Info (appropriate report output). Problems (identify existing problems) Collect Information This phase involves interviews with users, surveys by questionnaire, examining existing documents and observing users already on the system.

TASK 2 – Investigation Phase… Draw or find at least three pictures you think illustrate this phase, (think about the activities of this phase) Look at my example after you have finished

3 Analysis Phase - Apply Analysis Techniques Analyse Information Use of analysis techniques. data flow diagrams, charts, CASE tools Detailed analysis follows investigation and information gathering. The information obtained must be examined so that a deep understanding of the system to be developed is obtained. This is sometimes called requirement analysis. The system analyst uses diagrams, charts, data flow diagrams and may use CASE tools in order to produce alternative solutions to the problem domain.

3 Analysis Phase - Apply Analysis Techniques A prototypes is a demo version of the new system. It is unlikely to be a fully functioning system. Sometimes prototypes are developed for the users to assess. Often easier for users to assess their needs by reviewing prototypes rather than reviewing more abstract documentation. This is the last chance to identify problems or errors before the system is actually designed; the later an error is detected the more expensive it is to rectify. Finally, all the alternatives are examined and a recommendation is made. If the recommendation is accepted, the negotiated statement of requirements is drawn up and agreed upon by all parties.

3 Analysis Phase Negotiated Statement of User Requirements. The ultimate objective of the analysis stage is to produce a ‘Negotiated Statement of User Requirements' which is a system proposal approved by the users. We have seen that getting to this point involves… Analysis of the collected information using analysis techniques Collect Information The investigation phase involves interviews with users, surveys by questionnaire, examining existing documents and observing users already on the system. Analyse Information Use of analysis techniques. Data flow diagrams, charts, CASE tools Negotiated Statement of User Requirements.

TASK 3 – Analysis Phase… Draw or find at least three pictures you think illustrate this phase, (think about the activities of this phase) Look at my example after you have finished

4 Design Phase The designing of a system converts the 'Negotiated Statement of Requirements' into the 'System Specification'. This is a detailed set of documents that provide details of all features of the system: During this phase we plan HOW the system should be implemented Various pictures, diagrams, written documentation are produced that describe possible solutions One solution is chosen out of all the possible solutions Don’t get the wrong impression. This phase does NOT involve programming. What do we have to specify exactly? – All of this.

TASK 4 – Design Phase… Draw or find at least three pictures you think illustrate this phase, (think about the activities of this phase) Look at my example after you have finished

Implementing a system broadly involves: 5 Implementation This involves following the detail set out in the 'System Specification'. The new system is installed and becomes operational. The user becomes involved. Implementing a system broadly involves: Development & Testing of Programs. Conversion of Data Files (incorporate existing files). Staff Training (management / clerical / operators). Introduction of New Procedures (clerical duties). Installation & Changeover Plan ("going live")

TASK 5 – Implementation… Draw or find at least three pictures you think illustrate this phase, (think about the activities of this phase) Look at my example after you have finished

Testing a system broadly involves: 6 Testing Phase You should note that most of the testing phase will overlap with the implementation phase. Testing a system broadly involves: Unit Testing (test individual software modules). Integration Testing (test interfaces between software modules). System Testing (test complete system). Acceptance Testing (user tests the complete system). Which tests would have to be carried out during the implementation phase?

TASK 6 – Testing Phase… Draw or find at least three pictures you think illustrate this phase, (think about the activities of this phase) Look at my example after you have finished

This phase involves two sorts of activity. 7 Maintenance & Support The system is monitored; end-user interaction with the system is examined, trouble spots are identified, modifications may be made. This phase involves two sorts of activity. End user support may be required during the settling in period. This may take the form of help-desks or training. The actual programming code for the system may need changing - this is called 'Software Maintenance'. Even if there are no problems with the system, a time will come when the users’ information requirements alter and the system needs to be enhanced or update

TASK 7 – Maintenance Phase… Draw or find at least three pictures you think illustrate this phase, (think about the activities of this phase) Look at my example after you have finished

What's Next? Next Week – Methodologies: the tools & techniques for carrying out the activities of each phase

Systems Analysis and Design The END! Systems Analysis and Design