information systems defined small enterprise characteristics
DESCRIPTION
section I Introduction. for the Small Enterprise. Systems Analysis and Design. information systems defined small enterprise characteristics Information needs of the small enterprise the systems development life cycle computer information system components the role of the analyst - PowerPoint PPT PresentationTRANSCRIPT
information systems definedsmall enterprise characteristicsInformation needs of the small enterprisethe systems development life cyclecomputer information system componentsthe role of the analystmethodologies, tools, and techniquesthe enhanced SDLCportfolio project
Sys
tem
s A
nal
ysis
an
d D
esig
nfo
r th
e S
mal
l E
nte
rpri
se
section IIntroduction
Systems definition
• a set of entities, real or abstract, comprising a whole where each component interacts with or is related to at least one other component.
• Any object which has no relation with any other element of the system is not part of that system but rather of the system environment.
• A subsystem then is a set of elements, which is a system itself, and a part of the whole system.
• In other words . . .
Systems definition
• A system is composed of regularly interacting or interrelating groups of activities/parts which, when taken together, form a new whole. In most cases this whole has properties which cannot be found in the constituent elements.. . .
Systems definition example
Systems definition exampleCar as a System
• Car– Propulsion (engine)
• Fuel• Electrical
– Control• Braking• Steering• Acceleration
– Signal
– Safety• Starting• Seatbelts• Air bags
– Comfort• Temperature• Entertainment
– Radio
– TV / Video
– Monitoring• Speedometer• Odometer• Temperature• Oil
The concept of a system
6
How do the “rules” change
7
How do the “rules” change
8
Systems definition exampleSystem: An interrelated set of components, with an identifiable boundary, working together for some purpose
General System Depiction
Environment: Everything external to a system that interacts with the system.
General System Depiction
Boundary: The line that marks the inside and outside of a system and that sets off the system from its environment.
General System Depiction
Components: An irreducible part or aggregation of parts that make up a system, also called a subsystem..
General System Depiction
Interrelationship: Dependence of one subsystem on one or more subsystems.
General System Depiction
Input: Whatever a system takes from its environment in order to fulfill its purpose.
General System Depiction
Output: Whatever a system returns to its environment in order to fulfill its purpose.
General System Depiction
Interfaces: Point of contact where a system meets its environment or where subsystems meet each other.
Information Systems Defined
• An information system is a well-coordinated collection of resources that gather and transform data into information products and services that help the enterprise perform its designed functions
• An information system hierarchy associates different classifications of information systems with different audiences
17
18
Information System Hierarchy
Information Systems Defined
19
Three significant trends influence the evolution of information systems and provide opportunities for the entrepreneurial systems analyst:
• The emergence of small enterprise computing• The Internet as a dominating technology• The maturation of application software
Small Enterprise Characteristics
20
The following small enterprise characteristics influence the analyst’s work:
• Owner participation• Economic constraints• Competitive pressures
Information Needs of the Small Enterprise
21
The following are common information needs of any enterprise:
• Production and inventory• Personnel• Financial reporting• Marketing, sales, and service• Customer relations
Computing Terminology
22
TECHNOTE 1-1
Several software products are integral to the analyst’s work:
•Off-the shelf application software
•Software suites
•Computer assisted systems engineering (CASE)
•Object-oriented application software
The Systems Development Life Cycle
23
The systems development life cycle (SDLC) consists of five major phases:
• Analysis• Design• Development• Implementation• Maintenance
The Circular SDLC
24
The Recurring SDLC
25
Information System Components
26
There are six major information system components:
• People• Procedures• Software• Hardware• Networks• Data
Reference Figure 1-7: Information System Components
Software Classifications
27
TECHNOTE 1-2
System Software•Operating systems
•Firmware
•Utility
Application Software•Horizontal
•Vertical
•Turnkey
Customizable Software•Third-generation programming languages
•Fourth-generation programming language (4GL)
•Object-oriented programming language
•4GL products
The Role of the Analyst
28
• An agent of change• A problem-solving strategist• A group facilitator
• Four Sets of Analytical Skills– Systems Thinking– Organizational Knowledge– Problem Identification– Problem Analyzing and Solving
The Blurred Proportional SDLC
29
Methodologies, Tools, and Techniques
30
• CASE Tools• Systems Architect• Alternatives to CASE
technologies (VISIO)
The Enhanced SDLC
31
The enhanced SDLC embodies several important concepts:
• The recurring nature of the SDLC• The blending of several phases of the SDLC• The influence of the user throughout the SDLC• The addition of many powerful tools to assist
the analyst
The Enhanced SDLC
32
Chapter Summary (1/3)
33
• Small enterprise, PC-based computing should rely on proven systems theory and techniques
• The small enterprise approach presents special advantages for an introductory study of systems analysis
• The systems development life cycle provides a framework for creating a small enterprise information system
Chapter Summary (2/3)
34
• There are five phases of the SDLC:• Analysis• Design• Development• Implementation• Maintenance
• There are six components of an information system• People• Procedures• Software• Hardware• Networks• Data
Chapter Summary (3/3)
35
• A systems analyst is:– An agent of change– A problem solving strategist– A group facilitator
• Characteristics of a System – Components– Interrelated Components– Boundary– Purpose– Environment– Interfaces– Input– Output– Constraints