Transcript Chapter 1

Introduction to Information System Development
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IS that uses computer and communication
technology to perform tasks
Basic component:
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Hardware
Software
Database
Telecommunication
Procedures
People
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Physical component of computer system
System unit and motherboard are used to
support and tie other components together
Consists of:
 Input device
▪ Capture and translate data into a form that can be
processed and used by other parts of computer
▪ Eg: keyboard, pointing device, bar code scanner
 Computer is composed of the CPU and internal
memory
▪ CPU is the chip that performs the instructions received
from software
▪ Internal memory/Random Access Memory is a
temporary memory that hold software instruction and
information for CPU
▪ To permanently store info and recall them, information
need to be store in secondary storage device/external
memory
 Output device
▪ Provide copies of data and information on paper, video
screen, etc.
 Modems
▪ Input or output device that allow a computer to transfer
data between each other.
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Set of instructions
Eg: computer code that hardware devices
carry out to process info
Software is fundamental to computer
Database software is a software that allows
you to arrange, modify and extract data from
a database to create info
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Telecommunication is a vital computer based
tool to help communicate information to
people in other location
Computer network through the use of
communication technology can share
resources such as storage database and
processing power
Can send and receive information through
network
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Integral part of Information System
Includes management and end user
Manager use information to make decisions
End user supply data to Information System
and receive info from Information System
A series of steps undertaken in a prescribed manner
to accomplish a certain job
 Human activities requiring people to interact with
other components of IS
 Can be written in form of manual or documentation
such as diagram
 When procedures are embodied in computer
program, they are considered part of Information
Technology component
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System development lifecycle is a series of
recommended steps or phases designed as
guideline as to what you should do and when
you should do it
Actual number of phases and the name given
to each phase differs from one organisation
to another
It is simplified by combining some of the
phases
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The phases have a defined product or
deliverable
Deliverables can be used to monitor
productivity and quality of activities
performed
Phases may have more than one deliverable
SDLC use to organize activities needed to build a
system
Assist management by providing reports on
project status and keeping track of resource need
Consist of:
System planning
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Prior to developing Information System, long term and
short term planning must be done to prevent poor
analysis and design of new system
Preliminary investigation is a brief study of the problem.
Output of this step is the project goal, scope and
boundary and the terms of reference of the project
iv. May include any restrictions such as part of existing
system which cannot be changed, etc
v. Also include rough idea of resource requirement of next
phases
vi. The objective of IS project mgt is to deliver a system
that is acceptable to users and develop within time and
budget
vii. IS project mgt is the process of planning, scheduling and
controlling the activities during the SDL
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System analysis
2.
Is the detail understanding of important
features of system under investigation
ii. Include finding out how the existing system
works, problems and the user requirement of
the new system
iii. Determining accurate user information needs
and system requirements is important because
the design of new system will be based on these
determined requirement
i.
System design
3.
Information need and system requirement in system
analysis are studied in more detail
Can be divided into general and detail system design
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At the end of general system design, we will know what we
need to develop and may include what software to use
Detail system design/physical system design is the ext of
general design.
During this design, input, output, interface, database, network,
programme and control are defined and documented
System construction and implementation
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During system construction, the individual system
components are built
New programs and changes to existing program are
written and tested
During implementation, the component built during
construction are put into operational use
After the new system is completed and working, post
implementation review is performed to evaluate the
new system and suggest minor changes to be made
System maintenance
5.
To eliminate errors in the system
ii. Implies that there is continuous improvement of
the new system implemented
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Structured Development
 Employs a variety of diagrams and documentations for
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describing the requirement of IS
Eg: DFD, ERD and structured diagram
Involve users in developing the IS
User need to participate in the analysis and design process
as they are the people who use the system
Emphasis on logical system design
Major critics: takes too long and require too much
documentations
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Object-Oriented Development
 System developer first define the object needed
in the new or revised IS
 If object already exist, they are reused. If not they
will select an existing object that is closed to the
one needed and then modify the existing object
as necessary
 Unified Modeling Language (UML) is an object
oriented programming language use to describe
IS
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End user
 People who directly interact with IS
 Supply data to IS and receive info from IS
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Business analyst
 Analyses the business aspects and issues surrounding the
IS identifying how they will provide business value in
creating, developing and designing new procedure and
policies together with the system analyst
 Will have business exp and some type of professional
training
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System analyst
 Focuses in IS issue surrounding the system by identifying
how IT can improve business processes, design the IS and
the new business processes and ensure compliance with
std
 Responsible for planning, undertaking and coordinating
overall dev activities
 Likely to have significant training in analysis and design,
programming and even areas of business
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Infrastructure analyst
 Identify and implement infrastructure changes on
technical issues involve in how the system will
interact with the org’s infrastructure – Eg:
hardware, software, database, network
 Likely has significant training and exp in database
administration, networking and etc
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Change management analyst
 Focuses on people and mgt issues surrounding the IS
installation
 The roles include ensuring that adequate documentation
and support is available to user, provide user training on
the new system and developing strategies to overcome
resistance to change
 Likely have significant training and exp in organizational
behavior in general and change mgt in particular
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Project manager
 Oversees the system dev project from beginning
to end, manages the project team, dev and
monitors project plan, assign resources and act as
primary point of contract for the entire systems
project
 Likely have exp in project mgt and likely has work
for many years as system analyst