Matakuliah : M0304/Corporate Information System Management
Tahun
: 2008
Pertemuan - 15
Konsep Dasar Sistem INFORMASI
Fakultas Ilmu Komputer
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Pandangan Sistem
• Systems thinking is:
– a discipline for seeing wholes
– a framework for seeing interrelationships rather than things
– an antidote to feeling of helplessness when dealing with complexity
Peter Senge (1990)
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Pandangan Sistem
What Is a System?
System – a set of interrelated components that must work
together to achieve some common purpose
Fakultas Ilmu Komputer
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THE SYSTEMS VIEW
What Is a System?
All components are there … but they don’t work well together!
Fakultas Ilmu Komputer
Figure 15.1 Contoh Rancangan jelek
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THE SYSTEMS VIEW
What Is a System?
System – a set of interrelated components that must work
together to achieve some common purpose
Information System – the collection of IT, procedures, and
people responsible for the capture, movement,
management, and distribution of data and information
Fakultas Ilmu Komputer
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THE SYSTEMS VIEW
Seven Key System Elements
1. Boundary
2. Environment
3. Inputs
4. Outputs
5. Components
6. Interfaces
7. Storage
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Figure 15.2 General Structure of a System
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Figure 15.3 System Component Examples
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THE SYSTEMS VIEW
Seven Key System Elements – System Boundary
System boundary depends on:
1.
2.
3.
What can be controlled
What scope is manageable within a given time period
The impact of a boundary change
Fakultas Ilmu Komputer
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THE SYSTEMS VIEW
Seven Key System Elements – Component Decomposition
•
•
A component of a system is also called a subsystem or module
Hierarchical decomposition – the process of breaking down a
system into successive levels of subsystems, each showing more
detail
Fakultas Ilmu Komputer
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THE SYSTEMS VIEW
Seven Key System Elements – Component Decomposition
Goals of hierarchical decomposition:
1.
2.
3.
4.
5.
To cope with system complexity
To analyze or change part of the system
To design and build each subsystem at different times
To direct the attention of a target audience
To allow system components to operate more independently
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THE SYSTEMS VIEW
Seven Key System Elements – Interfaces
Interface – point of contact between a system and its
environment or between two subsystems
Functions of an interface:
–
–
–
–
–
–
Filtering
Coding/decoding
Error detection and correction
Buffer
Security
Summarizing
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THE SYSTEMS VIEW
Seven Key System Elements – Interfaces
Interfaces built between two preexisting systems are called bridges
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THE SYSTEMS VIEW
Seven Key System Elements – Interfaces
Possible objective of an interface:
–
System decoupling – changing two system components so that modifying
one does not necessarily require modifying the other
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Fakultas Ilmu Komputer
Figure 15.4 Sales Summary Reporting System
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Figure 9.4 Sales Summary Reporting Subsystem
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THE SYSTEMS VIEWHow does a change in one
Organizations as Systems
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affect the others?
Figure 15.5 Fundamental Components
of an Organization
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THE SYSTEMS VIEW
Systems Analysis and Design
Systems analysis and design (SA&D) – a process used in
developing new information systems based on a systems
approach to problem solving
Fundamental principles:
–
–
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Choose an appropriate scope (boundary selection)
Logical before physical (what before how)
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THE SYSTEMS VIEW
Systems Analysis and Design
Recommended problem-solving steps:
•
•
•
Problem (or system) is a set of problems that must be broken down into smaller, more
manageable problems
Single solution is not always obvious to all – alternatives should be generated and
considered
Understanding of problem changes, so reassess commitment to solution at various
stages
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BUSINESS PROCESSES
Business process – a set of work activities and resources
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One way managers can
evaluate a business process
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Figure 15.6 Evaluating Business Processes
(Keen, 1997)
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BUSINESS PROCESSES
Business Process Redesign
Business process reengineering (BPR) – radical business
redesign initiatives that attempt to achieve dramatic
improvements in business processes by questioning the
assumptions, or business rules, that underlie the
organization’s structures and procedures
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BUSINESS PROCESSES
Business Process Redesign
Six principles for redesigning business processes:
1.
2.
3.
Organize business processes around outcomes, not tasks
Assign those who use the output to perform the process
Integrate information processing into the work that produces the information
Fakultas Ilmu Komputer
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BUSINESS PROCESSES
Business Process Redesign
Six principles for redesigning business processes:
4.
5.
6.
Create a virtual enterprise by treating geographically distributed resources as though
they were centralized
Link parallel activities instead of integrating their results
Have the people who do the work make all the decisions, and let controls built into the
system monitor the process
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BUSINESS PROCESSES
Business Process Redesign
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Figure 15.7 How IT Enables New Ways to Work
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PROCESSES AND TECHNIQUES TO DELIVER INFORMATION
SYSTEMS
The Information Systems Life Cycle
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Figure 15.8 Generic Systems Life Cycle
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PROCESSES AND TECHNIQUES TO DELIVER INFORMATION
SYSTEMS
The Information Systems Life Cycle
Definition Phase:
•
End user and systems analysts conduct analysis of current system and business
processes
Analysis is:
•
–
–
•
Process-oriented
Data-oriented
Business case generated and solution chosen
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PROCESSES AND TECHNIQUES TO DELIVER INFORMATION
SYSTEMS
The Information Systems Life Cycle
Construction Phase:
•
•
•
•
•
•
System designed, built, and tested
System logically described, then physically
Technology chosen
Programs, inputs, and outputs designed
Software programmed and tested
User acceptance testing conducted
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PROCESSES AND TECHNIQUES TO DELIVER INFORMATION
SYSTEMS
The Information Systems Life Cycle
Implementation Phase:
•
•
Business managers and IS professionals install new system
Data and procedures from old system converted
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PROCESSES AND TECHNIQUES TO DELIVER INFORMATION
SYSTEMS
Structured Techniques for Life Cycle Development
System development methodology – framework consisting
of guidelines, tools, and techniques for managing skills to
address the business issue
•
•
Consists of processes, tools, techniques for developing systems
Prescribe who participates, roles, development stages and decision points, and formats
for documentation
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PROCESSES AND TECHNIQUES TO DELIVER INFORMATION
SYSTEMS
Structured Techniques for Life Cycle Development
Structured techniques – tools to document system needs,
requirements, functional features, dependencies, and
design decisions
•
•
Procedural-oriented
–
Most common
–
Include data-oriented, sequential, process-oriented activities
Object-oriented
–
Newer approach
–
Often used for GUIs and multimedia applications
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PROCESSES AND TECHNIQUES TO DELIVER INFORMATION
SYSTEMS
Procedural-Oriented Techniques
•
•
Provides a baseline for the new system
Includes both logical and physical models
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Figure 15.9 Three-Step Modeling Approach
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PROCESSES AND TECHNIQUES TO DELIVER INFORMATION
SYSTEMS
Procedural-Oriented Techniques
Critical appraisal of existing work processes to:
•
Identify major subprocesses, entities, and interactions
•
Separate processing from data flow
•
Capture relationships between data elements
•
Determine entities and processes within scope
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Figure 15.9 Three-Step Modeling Approach
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PROCESSES AND TECHNIQUES TO DELIVER INFORMATION
SYSTEMS
Procedural-Oriented Techniques
•
•
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Conducted by IS specialists
Maps logical requirements to available technology
Figure15.9 Three-Step Modeling Approach
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INFORMATION SYSTEMS
CONTROLS TO MINIMIZE
BUSINESS RISKS
•
Common system security risks:
–
Human error
–
Criminal acts
–
Due to staffing changes and project management deficiencies
–
Natural disasters
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INFORMATION SYSTEMS CONTROLS TO MINIMIZE
BUSINESS RISKS
Types of Control Mechanisms
•
Management policies
•
Operating procedures
•
Auditing function
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INFORMATION SYSTEMS CONTROLS TO MINIMIZE
BUSINESS RISKS
Types of Control Mechanisms
•
Controls built into the information system itself:
–
To maintain data integrity
–
Allow only authorized access
–
Ensure proper system operation
–
Protect against malfunctions, power outages, and disasters
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INFORMATION SYSTEMS CONTROLS TO MINIMIZE
BUSINESS RISKS
Types of Control Mechanisms
• IS Organization
– Backup power supplies
– Network access control
– Firewall protection
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• Business Organization
– Ensure accurate data entry and
handling
– Identify procedural errors
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INFORMATION SYSTEMS CONTROLS TO MINIMIZE
BUSINESS RISKS
Types of Control Mechanisms
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Figure 15.14 Pre- and Post-Installation Controls
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end
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