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samuel-williams
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Maintaining Information Systems
Class 27
SDLCProject Identification
& Selection
Project Initiation& Planning
Analysis
Logical Design
Physical Design
Implementation
Maintenance**
Maintenance Changes made to a system to fix
or enhance its functionality Why is it needed?
Types of Maintenance
Systems Life Cycle Design Concept
Plan
Analyze
DesignImplement
Maintain
System Maintenance Process Obtain maintenance requests
SSR, CR, SMR Transform requests into formal changes /
Identify what parts of the system need to be changed
Secure resources to implement the change Design, Code, TEST, and Implement chages Monitor changes Update HW, SW documentation
Managing Maintenance Controlling maintenance requests
Forms Review Committee Planning
Who does it?
Managing maintenance (cont) How is effectiveness (quality)
measured? Main point: without measuring and/or
tracking maintenance activities, you can’t improve.
Configuration / Version management
Cost of Maintenance
NewDevelopment
Maintenance
35-40% 40-60% 70-80%
1970’s 1980’s 1990’s
Maintenance Cost Factors
Defects Customers Documentation Personnel Tools Software Structure
Programmers Working on Maintenance
Programmers on Programmers on Year New Programs Maintenance1950 90 10
1960 8,500 1,5001970 65,000 35,0001980 1,200,000 800,0001990 3,000,000 4,000,0002000 4,000,000 6,000,000
CASE Tools for Maintenance
CASE
System Documents(DFDs, Screen Designs)
New Source Code New System Docs