3. System Development Life Cycle (SDLC)
⢠Development of Information System for
solving business problems is Information
System or Application Developmentâ
⢠Systems are designed and implemented using
a systematic development process â Systems
Analysis & Design
7. Investigation
1) Is there a business problem?
2) Reason of problem?
3) Will new & improved Information System
solve the problem?
4) Which is most feasible Information System
solution to problem?
11. Technical Feasibility
⢠Suggested technology exists? Acquired?
⢠Recommended solution handle sufficient data
required for new solution?
⢠Offer responses to enquiries from number of
users from different locations
⢠System expandable?
⢠Technical guarantee for accuracy ,reliability
and security?
12. Economic Feasibility
⢠Cost Benefit Analysis
⢠Cost of hardware ,software ,license ,personnel
,office space etc vis a vis benefits
⢠Recovery of costs?
13. Operational Feasibility
⢠Can people work with new system?
⢠Supported by Management & Users?
⢠Current methods acceptable to all?
⢠Change impact customers?
⢠Change slow down performance in any area?
16. SYSTEM ANALYSIS
⢠What to do?
⢠How to do?
⢠Systematic investigation of real or planned
system to determine function of the system &
how they relate to each other and to any
other system
⢠In software development , requirement phase
is most crucial .
⢠User controlled stage
17. Characteristics of System Analysis
⢠Top Down Approach
⢠Use of Tools and Techniques â Functional Diagrams ,
DFDs , process specs , Entity relationships with
techniques and models
⢠Abstraction of Model- Creation of physical and logical
model
⢠Iterative Development âImprovement in analysis and
design in current step ensures improvement in
previous steps
⢠Advanced Technology
⢠Prototype
20. Phases of System Analysis
⢠Requirement Determination /Fact finding â
study of current system and scope of
adjustments and improvements
⢠Data gathering activity done during Analysis
21. Data Flow Diagram (DFD)
⢠Graphical representation of data flow through
an Information System is called DFD
⢠Used for problem understanding and Analysis
of system
⢠Depicts flow of data through the system
⢠DFD captures the transformation of input data
to produce output data
⢠DFD reflects movements of data through the
different transformation in the system
22. Elements of DFD
⢠1.Process âActivity performed according to incoming
data flow or conditions â represented as âcircleâ or
ârectangleâ
⢠2Data Flow â Input /Output of data â represented by
âsolid line with arrowâ
⢠3 External Entity â Another department . A business,
person ,machine can be used to send or receive data to
and from the system . Represented by âsquareâ
⢠4.Data Store â Data is stored in âdata storeâ â
represented by âopen ended boxâ, inventory of data
24. Levels of DFD
⢠1.Context Diagram âhighest level in DFD â
single process representing entire system
⢠2. O Level Diagram â All process models have
only one level 0 DFD