Information System Analysis
Topic 1
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
interact
Delineate components and their interrelation
during analysis
2
A system is a whole
Be sure to define the entire system before
examining subsystems
3
Systems are goal-seeking
What is the goal of an information system
4
Systems have inputs and
outputs
A major design task is to specify inputs & outputs
5
Systems transform inputs to
yield output
A major design task is to specify 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 a hierarchical task,
systems consist of 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
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.
 A system is a collection of interrelated components (subsystems) that function
together to achieve some outcome (e.g. biological system, computer system,
social system)
 A subsystem is a system which is an element of a larger system. The large
system is called "Super System".
 Data are groups of characters recognized as having the lowest level meaning:
they are raw facts & opinions.
 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.
 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.
 Knowledge has the highest level of meaning because it represents information
that can be potentially useful in future decision situation.
 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.
 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 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
 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.
Example: a department store's financial system is structured to reflect the
interaction of the pricing, purchasing, inventory, and billing activities.
 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.
Example: a purchasing department might receive requests for material form the
factory and then generate purchase orders to be routed to vendors.
 Functional decomposition: dividing a system into components based on
subsystems (which are in turn further divided into subsystems)
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)
 System Environment: It is the source of the system inputs and destination for
the system outputs ( any thing outside the system’s boundary)
 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.
 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
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.
 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.)
 TPS eliminates the tedium of necessary operational transactions.
 TPS Reduces the time once required to perform them manually.
Note:
 TPS are boundary-spanning systems that permit the organization to interact with
external environment.
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.
 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.
 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 planning and controlling business.
 MIS support a broader spectrum of organizational tasks than TPS, including
decision analysis and decision making.
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.
 It is oriented to management control
 Standardized report & interrogative reports are major outputs of an MIS.
 It deals with well structured tasks
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.
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
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.
 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 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 investigation phase consists of:
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.
2. A Feasibility Study

You look at whether to move on to the analysis phase or not.

Here we have three aspects:-
A. Technically feasible :

With the technology we have, can we get the project done?
B. Can we obtain equipment and personal to develop, install and operate the
system? Economically feasible :

Determine whether the time and money are available to develop the system
C. It includes the estimated cost to purchase Hardware & Software. 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.
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:1. Determining the requirements of the system (it should be careful study)
2. Study these requirements and structure them according to their
interrelationships and eliminating any redundancies.
3. Generate alternative initial designs to match the requirements.
 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.
 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
 Implementation includes:1. Coding
2. Testing
3. Installation
4. Initial user support such as training programs
 During the operation the programmers make the changes that users ask for and
modify the system to reflect changing business conditions
 Note:o The documentation and training program are finalized during
implementation, documentation is produced throughout the life cycle.