Information System Analysis
Introduction
General System Theory
The basics of the general systems theory and the information
systems are:
General System Theory
Importance for information systems
1
Components of a system Delineate
components
interact
interrelation during analysis
and
their
2
A system is a whole
Be sure to define the entire
before examining subsystems
3
Systems are goal-seeking
What is the goal of an information system
4
Systems have inputs and A major design task is to specify inputs &
outputs
outputs
system
General System Theory
General System Theory
Importance for information systems
5
Systems transform inputs A major design task is to specify
to yield output
processing to produce outputs from inputs
6
Systems must be
controlled
Information systems help to control
organization, Information systems have to
have feedback on their own performance &
be controlled
7
Systems forms a
hierarchy
Information
systems
design
is
hierarchical task, systems consist
hierarchies of subsystems
8
Systems exhibit
differentiation
Information systems have many specialized
parts
9
Systems exhibit
equifinality
There are ways to design a system to
achieve desired goals
a
of
System Definition

A system is an organized collection of
people, machines, procedures, documents,
data, or any other entities such that they
interact with each other as well as with the
environment to reach a predefined goal.
System Definition

A system is a collection
components (subsystems)
together to achieve some
biological system, computer
system)
of interrelated
that function
outcome (e.g.
system, social
System Definition

A subsystem is a system which is an
element of a larger system. The large system
is called "Super System".
System Definition

Data are groups of characters recognized as
having the lowest level meaning: they are
raw facts & opinions.
System Definition

Information is data, which has been
processed to become meaningful to the
users, and upper management.

Information has more meaning than data in
that is useful in a present decision situation.
System Definition

A message is a group of characters that is
stored, processed and transmitted in the
information system of an organization.

In other words: information in an organization
is stored, processed, and transmitted as
messages.
System Definition

Knowledge has the highest level of meaning
because it represents information that can be
potentially useful in future decision situation.
System Definition

Information System The information system
of an organization may be defined as a
system that serves to provide information
within the organization when & where it is
needed in any managerial level.
System Definition

Information system is a collection of
interrelated
components
that
collect,
process, store and provide as output the
information needed to complete business
tasks (e.g. payroll system)
System Definition

System Analysis: the process of understanding and
specifying in detail what the information system
should do.

System Analyst: A professional who used analysis
and design techniques to solve business problems
(involving information technology)
Characteristics of Systems:
A system must have:
Purpose: systems do not just appear out of
nowhere, they exit for a purpose.
Example: an airline system transports passengers
Characteristics of Systems:

Structure: a system must be organized in
a way that gives it structure. The
components of the system must work
together in some preplanned way, so the
system can operate in an orderly manner.
Characteristics of Systems:
Example:
A department store's financial system is
structured to reflect the interaction of the
pricing, purchasing, inventory, and billing
activities.
Characteristics of Systems:

Interdependence: In order for a system to
function, it must receive input from other
systems. The system processes the input to
produce output, which is used as required
input for still another system. In other
words, a system interacts with the
environment in which it operates.
Characteristics of Systems:
Example:
a purchasing department might receive
requests for material form the factory and
then generate purchase orders to be routed
to vendors.
Characteristics of Systems:

Functional decomposition: dividing a
system into components based on
subsystems (which are in turn further
divided into subsystems)
Characteristics of Systems:
Example:
A hospital may have separate subsystems
for the pharmacy, the laboratory, and the
patient medical records.
In addition, each of these subsystems may
have subsystems of its own.
Elements of systems:

System boundary: the separation between
a system and its environment (where inputs
and outputs cross)
Elements of systems:

System Environment: It is the source of the
system inputs and destination for the system
outputs ( any thing outside the system’s
boundary)
Elements of systems:

System Inputs: are the physical objects and
data that cross the system’s boundary to
communicate with it.

System Outputs: are the physical objects
and Information that produced by the system.
Elements of systems:

Processing: is the conversion of inputs to
outputs.

Data processing activities include sorting,
searching, merging, summarizing, calculating,
and similar operations
General Depiction of a System
input
boundary
interrelationship
subsystem
output
Types of Information Systems
1.
Transaction processing systems (TPS):

TPS are computerized information systems
that were developed to process large
amounts of data for routine business
transactions such as payroll.
Types of Information Systems

TPS are information system applications
that capture and record information about
the transactions that affect the organization
(e.g. the sale of an item, a withdrawal from
an ATM etc.)
Types of Information Systems

TPS eliminates the tedium of necessary
operational transactions.

TPS Reduces the time once required to
perform them manually.
Types of Information Systems
Note:

TPS are boundary-spanning systems that
permit the organization to interact with
external environment.
Types of Information Systems
2.
Management Information Systems (MIS)

MIS may be defined as "a system that collects and
processes data (information) and provides it to
managers at all levels who use it for decision
making, planning, program implementation, and
control". An information system is comprised of all
the components that collect, manipulate, and
disseminate data or information.
Types of Information Systems

It usually includes hardware, software,
people, communications systems such as
telephone lines, and the data itself. The
activities involved include inputting data,
processing of data into information, storage
of data and information, and the production
of outputs such as management reports.
Types of Information Systems

MIS do not replace TPS; rather, all MIS
include transaction processing.

So, it takes information captured by the
TPS and produce reports management
needs
for
business.
planning
and
controlling
Types of Information Systems

MIS
support
a
broader
spectrum
of
organizational tasks than TPS, including
decision analysis and decision making.
Types of Information Systems
Finally:
MIS focus on information not on data

MIS are designed from an organizational
perspective rather than from a business
transactions perspective.

Its users are primarily the middle & upper
management.
Types of Information Systems

It is oriented to management control

Standardized report & interrogative reports
are major outputs of an MIS.

It deals with well structured tasks
Types of Information Systems
3.



Decision Support Systems (DSS)
A higher-level class of computerized
information systems.
The DSS is similar to the traditional MIS,
because they both depend on a database
as a source of data.
DSS departs from the traditional MIS
because it emphasize the support of
decision making in all its phases.
Types of Information Systems
Finally:
DSS focus on knowledge & on decision

It’s user initiated & controlled

It is oriented to the individual manager

It supports strategic planning

The major output (s) of DSS is interactive/iterative
reports

It deals with semi-structured & unstructured
problems
Types of Information Systems
4.
Expert Systems & Artificial Intelligence

An expert system is a programmed
decision-making information system that
captures and reproduces the knowledge of
an expert problem solver or decision maker
and then simulates the “thinking” or
“actions” of that expert.
Types of Information Systems

Expert systems are implemented with
artificial
intelligence
technology
that
captures, stores, and provides access to the
reasoning of the experts.
The System Development Life Cycle
(SDLC)

System Development Life Cycle (SDLC) is
the
overall
process
of
developing
information systems through a multistep
process from investigation of initial
requirements through analysis, design,
implementation and maintenance.
The System Development Life Cycle
(SDLC)
The major phases of SDLC:
Preliminary Investigation and feasibility Study

Planning Phase

Analysis Phase

Design Phase

Implementation and Operation

Evaluation and Maintenances
Preliminary Investigation and
feasibility Study

This phase identifies clearly the nature and
scope of the problem.

The
preliminary
consists of:
investigation
phase
Preliminary Investigation and
feasibility Study
1.
A Problem Statement/Objective

Identify where you are now and where you
want to get by performing this project.
Ask many different questions to a variety of
people in order to get a good idea of what they
have in mind.

Preliminary Investigation and
feasibility Study
2.
A Feasibility Study

You look at whether to move on to the analysis
phase or not.
Here we have three aspects:-

Preliminary Investigation and
feasibility Study
A.
Technically feasible :

With the technology we have, can we get the
project done?

Can we obtain equipment and personal to develop,
install and operate the system?
Preliminary Investigation and
feasibility Study
B.
Economically feasible :

Determine whether the time and money are
available to develop the system

It includes the estimated cost to purchase
Hardware & Software.
Preliminary Investigation and
feasibility Study
C.
Operational Feasibility

Determine if the human resources are available to
operate the system once it has been installed.

Users that do not want a new system may prevent
it from becoming operationally feasible.
Preliminary Investigation and
feasibility Study
3.
Preliminary Investigation Report

Prepare this report for management and it should
specify the identified problems and what further
action is recommended.
Planning phase


Here, the engineer gathers information
about the problem and the requirements.
He/she then sets criteria and constraints for
a solution and generates a number of
alternative solutions.
Analysis Phase


The analyst studies the organization’s
current procedures and the information
systems used to perform tasks such as
payroll.
Analysis has several sub phases:-
Analysis Phase
1.
2.
3.
Determining the requirements of the system (it
should be careful study)
Study these requirements and structure them
according to their interrelationships and eliminating
any redundancies.
Generate alternative initial designs to match the
requirements.
Analysis Phase

The output of the analysis phase is a
description of the alternative solution
recommended by the analysis team.
Design Phase

It defined as the creation of a new system in
accordance with a preconceived plan from
the analysis phase.
Design Phase

–
–
–
–
–
–
Activities:Design and integrate the network
Design the user interfaces
Design the system interfaces
Design and integrate the database
Prototype for design details
Design and integrate the system controls
Implementation & Operation

1.
2.
3.
4.
Implementation includes:Coding
Testing
Installation
Initial user support such as training
programs
Implementation & Operation

During the operation the programmers make
the changes that users ask for and modify the
system to reflect changing business conditions

Note:The documentation and training program are
finalized during implementation, documentation
is produced throughout the life cycle.