Class 15 System Life Cycle. Outline System Life Cycle (Structured & Rapid methodologies) System Planning (3 strategic goals) SLC Activities System Life.

Class 15Class 15

System Life CycleSystem Life Cycle

Outline

System Life Cycle (Structured & Rapid methodologies)

System Planning (3 strategic goals)

SLC Activities

System Life CycleInformation Systems for

Management 2


Management 3

System Life Cycle (SLC)

SLC = activities an IS goes through its inception to/phases can be run in sequence or in iteration.

- Waterfall (structured) methodology: Development activities make separate phases thatrun in linear sequence without repetition.

- Pro: Precise planning of time & resources *

- Con: Long development cycle** &less responsive to business change

Installation Cons

truc

tio

n

Systems Planning

Phase out


Management 4Information Systems for

Management 4Information Systems for

Management 4

Alternative: Rapid Methodologies

Strengths (pros) Weaknesses (cons)

Fast and more responsive to changes in business

May not suit large complex systems

Useful when systems requirements are uncertain or business changes fast

Can miss some steps in analysis, documentation and testing

Promotes user involvement in SLC

• Newer methodology based on faster development technologies and quickly changing business needs. Project time usually under 1 year.

• Development activities repeated for each part of system. Steps: • Identify some of user’s requirements (e.g., a key function of the IS)• Develop a function prototype, needed part of database, and access

screens• Test prototype & learn from users• Revise & enhance prototype based on users’ opinions• Test, roll out, and move to the next piece of the system


Management 5

What organizational changes can be accomplished with new system:

Automation of manual tasks (e.g., MIS, DSS, Expert system, communication systems)

Business Process Reengineering (BPR) - radical change of organization; process efficiency key goal*

Quality improvements (Benchmarking – test of compliance with standards)**

Systems Planning


Management 6

Systems AnalysisAnalysis of organizational needs to be met with an information system focusing on

1. data/information as part of jobs and tasks2. data transformation (data processing aspect on an IS)

1. Data analysis: define Information NeedsIdentifies what data are needed by particular members of an organization (your data diagram)Collect business documents (financial papers, reports…), interview users & managers

2. Software processes transforming data

Parts of a database


Management 7

Systems Design

Creating IS-based solution for meeting organization’s

information and management needs

Design encompasses:

Data (usually some database)

Software processes applied to data (functionality)

User Interface (screens for data input and for the output)

Programming/Construction follows (can be putting together of

purchased of-the-shelf software)*


Management 8

Testing

Testing – assessing quality of the developed system

Kinds of tests applied that from smaller parts to a large

system:

Unit testing (test each system function separately)

Cross-unit testing (test functions that depend on

each other)

System testing (tests IS as a whole; e.g., overload

the system to see how robust it is)


Management 9

Installation MethodsDirect cutover

New system completely replaces old one at a certain date

Parallel installationOld and new system used in parallel, until the new system proves reliable

Phased installationNew system introduced part by part and the old system phased out gradually (a new system turned on function by function or entirely in one part of a firm)

timeOld IS New IS

timeOld IS

New IS

time Old IS

New IS Function

New IS Function

Old Functions phased out


Management 10

Production Stage and Maintenance

System is being used for organizational needs

Operate the system

Evaluate the system

Maintain the system (modify it as needed – work out

software bugs, improve user interface, increase

secondary storage)

Class 15 System Life Cycle. Outline System Life Cycle (Structured & Rapid methodologies) System Planning (3 strategic goals) SLC Activities System Life.

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