Maintaining Information
Systems
Class 27
SDLC
Project 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
Maintain
Implement
Analyze
Design
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
Maintenance
1970’s
1980’s
35-40%
New
Development
40-60%
1990’s
70-80%
Maintenance Cost Factors






Defects
Customers
Documentation
Personnel
Tools
Software Structure
Programmers Working on
Maintenance
Year
1950
1960
1970
1980
1990
2000
Programmers on
New Programs
90
8,500
65,000
1,200,000
3,000,000
4,000,000
Programmers on
Maintenance
10
1,500
35,000
800,000
4,000,000
6,000,000
CASE Tools for Maintenance
System Documents
(DFDs, Screen Designs)
CASE
New Source Code
New System Docs