systems analysis

System Analysis Overview : 

System Analysis Overview

Slide 2: 

System analysis is an in depth study of end users information needs that produce functional requirements that are used as the basis for the design of a new information system

Activities : 

Activities Requirements Modeling Data modeling Process modeling Object modeling Transition to system design

Analysis phase activities : 

Analysis phase activities Gather information- Fact finding Define system requirements- Requirements Modeling Prioritize requirements- Requirements modeling Prototype for feasibility and discovery Generate and evaluate alternatives Review recommendations with Management

Slide 5: 

System requirement check list includes: Outputs :Reports- Type, frequency Inputs : How is data entered into the system-forms Processes Performance Controls Scalability and total cost of ownership

Slide 6: 

Fact finding : Finding answers to 5 questions Who , What, when ,Where, and How for the Current system and the proposed system; Current system Vs Proposed system Techniques: Interviews Document review Observation Questionnaires and surveys Sampling Research

Slide 7: 

The type of information gathered involves understanding the existing system , identifying and understanding all current and future users identifying all present and future locations where work goes on and identifying all system interfaces with other systems inside and outside the organization.

Modeling requrements : 

Modeling requrements Define system requirements Functional requirements: Specify information system capabilities required to meet the information needs of users Technical requirements : System Performance requirements, expected volume of transactions the system would be required to handle

Slide 10: 

System requirement check list includes: Outputs :Reports- Type, frequency Inputs : How is data entered into the system-forms Processes Performance Controls Scalability and total Cost of Ownership

Slide 11: 

Use Models and other documentation tools to visualize and describe the present system Functional decomposition diagram is a top down of business functions and processes Requirement modeling: Involves investigation and fact- finding to describe the present system and define the requirements for the new system FDD is used to model business functions and show how they are organized into lower level processes

Slide 12: 

Human resources Finance and Accounting Library operations Personnel Management Book Management Operating budget Fund raising New User Accquisition Check out and Return Books Add and Remove Books User Update Report generation Archive check out& User list

Slide 13: 

The requirement model that is generated called a logical model. A logical model is one that shows what the system is required to do in great detail without committing to any one technology A physical model on the other hand shows how the system will be actually implemented E.G : A logical model might specify an output as a list of data elements without comitting to either paper or on screen formats for the data

Slide 14: 

The requirement model that is generated called a logical model. A logical model is one that shows what the system is required to do in great detail without committing to any one technology A physical model on the other hand shows how the system will be actually implemented E.G : A logical model might specify an output as a list of data elements without comimtting to either paper or on screen formats for the data

Slide 15: 

A physical model of out put would include details of the format System analysis : Create detailed logical models System design : Creates detailed physical models Design alternatives created at the analysis stage : Preliminary physical models

Slide 16: 

Deciding on what is absolutely required and what is not is called prioritizing Resources are limited What are the most important thing s that the system must do

Data and process modeling : 

Data and process modeling Data flow diagrams – Process Modeling : Structured english, process specifcations , decision tree , process decompositon DFD Entity relationship diagrams: Data modeling

Prototyping : 

Prototyping Feasibility Prototyping : A prototype is created Particularly when the technology is new and hand experience working with it can be very helpful and establish the feasibility of the technology Prototyping for feasibility is increasingly important when working with new or recently upgraded technologies to assess the possibilities and limitations of the of the technology early in the process

Slide 19: 

Discovery prototyping: If the new system includes new or innovative technology it might be necessary to help the users to visualize the possibilities when defining what they require. Generate and Evaluate Alternatives : Generate alternative systems and Choose based on a Cost benefit analysis