Maintaining Information Systems Class 27. SDLC Project Identification & Selection Project...

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