Traditional Systems
Development
Details on the Systems
Development Life Cycle
approach to design.
Planning
Business
•Priority
•Feasibility
Analysis
Technical
Design
Implementation
Operations
Maintenance
SDLC: Project Management
Manage development schedule and cost
Make average contributors more effective
Prevent genius members from creating a
system that cannot be maintained
Initial Investigation
What is the system supposed to do and
what priority should we give it?
On IS budget
Memo or oral
Define user’s general expectations
Business justification
Rough cost
Assign priority
How do we find problems?
Dictated by business projects
Competitive initiative
Surveillance
Reaction
Opportunistic
Frameworks
Competitive strategy
Value Chain
Initial Investigation
 State the business problem.
 Summarize the proposed IT solution.
 Show how the proposed solution
contributes to the fundamental business
goals.
Strategic model
 Estimate net benefits.
Response Strategies
Low Cost Provider
Differentiation
Excellence
Customer Service
Niche Market
Feasibility Study
How Should we do it?
Feasibility Study
Formal report
On user budget
What should we do?
How should we do it?
What should it cost?
How will we use it?
Feasibility: TELOS
Technical: how can we do it?
Economic: is it cost justifiable?
Legal: are there legal issues?
Operational: does this fit the way we
want to do business?
Schedule: can we get it done on time?
Format:
Include these sections
Title page
Table of contents
Executive summary
Problem statement
Analysis of alternatives
Cost and benefits
Recommendation
Request for authorization
Appendix
Business Decomposition
What are the business
components of the system?
Babysitter Service
The AITP Service Club wants to run a
babysitting service. Customers call to
request a sitter and the Club Coordinator
assigns an employee to sit for the
customer from a list of employees
available for the particular day requested.
Functional Decomposition
Determine Employee Availability
Assign Employees to Job
Accept Call
Record Customer
Record Job
Assign Employee
Confirm Assignment
Data Decomposition
Employees
Customers
Jobs
Function/Data Interaction
Matrix
Employee Customer Job
Determine Employee
Availability
Schedule Jobs
 Accept Call
 Record Customer
 Record Job
 Assign Employee
 Confirm Assignment
Location
Reach: Where should it be available
Range: What functions should it support
Response: How quickly must it respond
General Analysis
Specify logical system
requirements
TOP DOWN DATA
ANALYSIS
– Computer systems are extremely complicated
and cannot be developed without careful
planning. The first step is generally to build a
model of the information system based on
the general objectives and goals it must
meet. This is called top down modeling.
E-R Diagram
Employee
Customer
Job
Data-Flow Model
• A logical representation of the processes
and data transformation of a system or
organization in graphical form
Context Diagram
Customer
Request
Confirirmation
Babysitter
Information
System
Availability
Assignment
Employee
Level 1 DFD
Request
Assignment
Confirirm- 1.
ation
Assign
Employee
New
Current
D1 | Customer
Availability
Avail
Times
Job
Assign
2.
Offer
Availability
Avail
Times
D2 | Employee
D3 | Jobs
Communications Model
• A representation of the location at which data is
stored and processed and the communications
links that connect them.
General Systems Analysis
Understand the current system
Be sure you don’t omit essential features
Obtain detailed specifications of expected
functions
Operations level requirements
Provide specifications for IT developers to
design from
General Analysis
Is this an information system or a
reengineering project?
Reengineering requires a mandate to change
the way you do business, and requires a
major commitment from all participants.
Most information systems are written to
support existing processes.
Detailed Conceptual and
Physical Design
Computer system structure and
module specification
System Implementation
Build it
Development
Structured Code
CASE tools
Code generators
Rapid Application Development
Object Oriented development
Prototypes
Testing
Walkthroughs and code inspection
Application test
Unit test - each program
System test - whole system together
Processes and user acceptance
Installation
Conversion
Direct
Phased
Pilot
Parallel
Training
Operations acceptance
Maintenance
Everything after
acceptance