SAD Summary

8/8/2019 SAD Summary

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SAD) Introduction to Information SystemsSystem: A set of related components, which can process input to produce a certain output.

Information System (IS): A combination of hardware, software and telecommunication systems, which can support business

operations to increase productivity, and help managers make decisions.

i) Components of IS: Five

(1) Hardware: The physical embodiment of an information system. It is one of the main elements which create the

information system cycle. Basic Hardware of a Computer: Input, Process, Output & Storage hardware

(2) Software:

(a) System Software controls the computer and contains the operating system and device drivers, which can

communicate with the hardware.

(b) Application Software contains programs which can help users and enable companies to perform business functions.

(3) Data: Refers to the raw facts on anything or entities like student names, courses and marks.

(a) Information: An organised, meaningful and useful interpretation of data

(4) Process: A guide consisting of orderly steps, which need to be followed and implemented in order to get a certain

decision on a certain matter.

(5) Human (Users): Managers and the Users are the people to whom the invaluable information has to be provided by

the Information System as a main objective.

3 Categories of Users:

(a) End-Users: Consists of the staff, customers, suppliers and others who communicate with the information system.

(b) Internal Users: Includes the managers, technicians, sales representatives and corporate officers.

(c) External Users: Consists of the customers who use the company's system for performing transactions, suppliers

who use the system for planning sales, and the staff who use the system outside office hours.

Categories of IS: Six

) Transaction Processing System: Access and record information about all transactions related to the organisation. Eg sales

der processing, accounts receivable, accounts payable, inventory and ordering as well as payroll

) Management Information System: Takes information extracted from TPS and generate reports which are required by the

anagement for planning and controlling a company's business.

) Executive Information System: Decision support system specifically used by the executive management in making strategic

cisions.

) Decision Support System: Focuses on the effectiveness of the manager in analysing the information and making a decision.

used for handling decisions that are not structured, i.e. decisions which are made when an emergency happens.

) Office Information System: Wider than word processing and form processing, This information system covers activities in th

fice, which can improve work flow and communication among workers, whether inside or outside the office.

) Expert System: a program that produces a decision which is almost similar to decisions made by an expert in a certain

scipline.

) Two impacts of IS on business operations

) Many companies today use information as a basis to increase productivity, producing quality products, providing quality

rvices, creating customer confidence, and making timely decisions.

) Information technology has become the prime reason for the success and failure of a company to compete in business.

Systems Analyst: Responsible for planning, analysing and implementing information systems.

) Individuals in the IS: i) Systems Owner: Bears the cost of system development and maintenance, has the right over the

ystem, determines the interest over the system and determines the policies over its use. Thinks of return value. ii) Systems

ser: An individual who uses the system for producing something


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) Internal User: Employees who work in the company to develop the information system.

) Mobile User: Users who often do jobs outside the company. Eg Salesmen and Sales representatives.

(3) External User: Other organisations, partners, suppliers,

customers and end users connected to the system iii) Systems

Designer: Experts in the technical field who would design a

system for fulfilling the needs of users.

iv) Systems Developer: Experts in the technical field who would develop, test and produce a system, which can operate

successfully, based on the design specifications of the system designers.

e) Business Profile, Model and Process:

Business Profile covers ownership, structure, and management of the company, together with its customers

and suppliers.

Business Model: Can take the form of a brick-and-mortar type, a virtual store, and so on.

) Business Process: Explains a certain process, activity, and the results expected, begins with the customer and ends with the

customer.

2) Information System Development: Methodology & Toolsa) System Development Methodology: A comprehensive plan to be followed, which covers all the necessary activities in the

system's development life cycle. b) Methodologies: includes the model to be followed, plus the tools and techniques to be

used. i) Model: A graphical presentation which can represent a real situation or a real world. Most models used are in graphicform, known as graphs and charts. ii) Tools: Supporting software used to create models or other components that are needed

in a certain project. iii) Technique: A strategy which can be used for implementing a specific system development activity.

c) Systems Development Life Cycle (SDLC): Complete process for developing information systems, which begins with the initia

investigation phase and ends with the operations and support phase. i) Phase 1: Initial Investigation: To identify problems or

information requirements. Delivers Initial investigation report. ii) Phase 2: System Analysis: To study the current system and tdetermine the new system requirements. Delivers System requirements documentation. iii) Phase 3: System Design: To desig

a new information system. Delivers System design specifications iv) Phase 4: System Development and Implementation: To

develop, acquire and test new hardware and software. To install and to adapt for the users environment. Delivers A Complete

Information System v) Phase 5: Support and Operation: To maintain and evaluate the system. Delivers An operational

Information System

Approaches to Systems Development:

Structured Analysis Approach: a traditional systems development method easy to understand. Uses a series of phases, called

e system development life cycle (SDLC), to plan, analyze, design, implement and maintain an information system.

Object-oriented Analysis and Design (OOAD): Combines data and the processes (called methods) into single item called

jects. OOAD is an approach that is intended to facilitate the development of systems that must change rapidly in response to

namic business environments.


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) Objects: Persons, places or things that are relevant to the system.

) Class: Defines the set of shared attributes and behaviours found in each object in the class.

) Attribute: Describes some property that is possessed by all objects of the class

) Method: An action that can be requested from any object of the class

) Object-oriented analysis (OOA) looks at the problem domain, with the aim of producing a conceptual model of the

formation that exists in the area being analyzed.

) Object-oriented design (OOD) transforms the conceptual model produced in object-oriented analysis to take into account o

e constraints imposed by the chosen architecture and any non-functional, technological or environmental constraints, such as

ansaction throughput, response time, run-time platform, development environment, or programming language.

iii) Information Engineering Approach: Concentrates more on the collection of information, focusing on strategic

planning, data modelling and hardware automation. The main activity of this approach is to study the business

mission, the objectives and to identify its information system architecture, and to plan how to manipulate

information systems for helping organisations achieve their business objectives.

iv) Rapid Application Development (RAD) Approach: Used to speed-up activities and processes found inside every phas

of system development, such as speeding-up the analysis phase by scheduling intensive meetings among the partie

involved for the purpose of information collection. In this way, decisions on a certain matter can be made

immediately and rapidly.

) Iterative development: An approach that is combined with RAD, similar to the Spiral Life Cycle Model. This model is capable

speeding-up the acquisition process up to the design and implementation phases.

) Prototype system building during the analysis and design phases of System Development Life Cycle (SDLC) can also speed-up

e development process.

3) Information System Development: Project Management a) Four types of Skills needed by a SystemsAnalyst: i) Knowledge on Business and Organisation ii) Skills in Solving Problems iii) Skills in Inter-personal Communication iv)

Knowledge and Skills in Information Technology

b) Project: Set of related activities which require a certain time-duration to be completed by using a pre-defined set of


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resources. Elements that a project contains are; time, budget and objective.

c) Project Management: Use of knowledge, skills, tools and also certain techniques on activities of a certain project to fulfil a

requirement and to satisfy the wishes of the project stakeholders.

d) Project Planning: An activity which divides the phases that need to be executed inside a certain project into smaller units

to simplify management.

e) Factors leading to an IS request: i) Failure of the Old System: Due to old hardware or old software with constraints to

upgrade. ii) Legal Requirements: The government may introduce new tax rates or other laws. iii) New Industry

Standards: Failure to conform to the standard practices of the industry may result in the company losing its linkages and

competitiveness. Eg. ATM, bar-coding, online payment, etc.

iv) To Exploit New Technology: Internet technology, mobile devices, physical tracking, etc. These new technologies can

improve performances several times, or can cut down on manpower costs a great deal, thus making its operations more

competitive.

v) To Improve Services: Improve or add additional services to users and customers. Eg. Enable share investors to check

their account balances on the Website, saving data about taxis, etc

vi) More Information: The current system may not provide information required by the organisation. vii) More

Stable Control: A system may need to add on new effective controls to ensure that data is accurate and safe. Eg.

Passwords, various levels of user access, and encryption or data encoders. etcviii) Reducing Operating Cost:

Operating costs of the existing system may incur high updating costs due to technical problems, poor design, or

changing requirements in terms of the business direction.

Evaluating a System Request:

i) Evaluation Committee: In larger organisations, one committee is formed to bring together various skills and knowledge

for evaluating system requests. This committee normally consists of the information technology director and various

departmental managers.

ii) Evaluating Feasibility:

) Objectives of the feasibility evaluation:

) To determine the feasibility of an information system;

) If the project is suitable, a re-study on the factors that determine its priority will be done;

) To determine whether there is a relationship between this project and another project; and

) To obtain the terms of reference for the project.

) Three main yardsticks to measure or to ensure the success of the system to be developed:

) Operational feasibility: Tries to measure how far the solution proposed can be used by the organisation.

) Technical feasibility: Is present in a system request if the organisation has the resources to develop or buy, and to operate

e system at user locations.

) Economic feasibility: Tries to answer the question of whether the system to be introduced can be developed within


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dgetary constraints, and whether it can improve the organisation's economy by giving back in the form of benefits.

) Tangible Benefits: Benefits that can be measured in the form of money, or those that can be easily quantified.

i) Intangible Benefits: Difficult to measure in monetary form, but this category needs to be identified. They can be of strategic

portance that may override the numerical benefits

Initial Investigation of the system can be defined as an initial study on a certain project before making a decision on whether

or not the project can be continued. i) Activities inside Initial Investigation:

) Understanding Organisation's Problems and Opportunities

) Determining Project Scope and Limitations

) Doing Information Search

) Determining Project Feasibility

) Estimating Time and Cost in Order to Proceed with Development

) Presenting a Proposal to the Management

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) Determination ofSystem RequirementsFunctional Requirements: System requirements that are concerned with functions or process that needs to be performed by

e system. Eg. Record Customer Information, Accept Payments, Generate Reports etc.b) Non-Functional Requirements: System

quirements that are concerned with anything else other than functions. They constitute operational objectives that are relate

hardware, software, the environment, etc. Eg. Ability to operate in the client-server and Unix environment, Ability to process

-line etc.c) Stakeholders: Individuals who have interests in the information system. 3 Categories: i) Users: People who use the system

daily.

) Business Users: use the system for performing the daily operation activities or functions of an organisation. These daily

erations are also known as transactions.

) Information Users: are individuals who need current information from the system. Can be present inside or outside the

ganisation, and they include customers.

) Management Users: need information that is brief and detailed from the system.

) Executive Users: are made up of managers at the top level. They prepare for organisation's strategic plan for duration of five

n, or twenty years.

) External Users: System's access by users who are present outside the organisation can be made easily via the Internet.

) Owners: People who own and pay for the system. iii) Technical Staff: People who ensure that the system operates in the

ganisational computing environment.d) Two of the most important skills in System Analysis are:

i) Fact finding to identify system requirements,

ii) Business process modelling based on the system requirements

e) Work Procedure explains the way a certain job is performed by an individual or a group of individuals, together with data

being used, and information being produced in the job.

f) Formal System: A system that is identified by official documentation of the organisation g) Informal

System: Actual way jobs are done in the organisation. Informal systems exist because of the work habit and

individual's preference, conflicts, and other factors.


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h) System Report is the third type of report that is of no less importance. As the main output of a system, reports

enable us to know which data are important to produce the report.

i) Techniques used in fact finding (collect information): i) Looking at Current Documents ii) Interview: In this technique, the

analyst meets with users

individually or in a group. However, it is not practical if it involves a large number of individuals because it takes a

long time, costs a lot, and only a limited number of questions can be asked.

) Open Questions allow users to answer spontaneously in whatever way that is suitable. Open questions are suitable if you

ant to understand a complex process or to get an opinion, attitude or proposals of the user.

) Closed Questions limit the answers to shorter and limited set of answers, or specific alternatives. Closed questions are asked

you want information that is more specific, or when you want to confirm facts.

iii) Questionnaires: Addresses the problems in interviews, can be printed in large volumes and can be distributed to

respondents at a cost that is not too high per individual.

) Free Format the space and style that is more flexible to the respondents to answer. Respondents will answer inside the spac

ovided, just below the free format question.

) Fixed Format consists of questions that require respondents to choose an answer from a limited choice. Respondents need t

swer based on the given alternatives only. This simplifies the answer to be collected for entering into the table.

) Observation: Personally looking at the working system in operation, you can understand better the business process being

executed, and you can see the system in a different perspective. Enables you to confirm information from the interviews

besides ensuring that the business process operates as stated

Prototype: An initial model of a complete system. It represents parts of the entire system, and so is certainly not a complete

system.

Joint Application Design (JAD): A technique for determining system requirements or system design rapidly that involves all

the related participants in a single session.

) Facilitator: An individual with the experience and skills in the conduct of JAD sessions. He determines the meeting agenda

d provides guidance on discussion, but does not participate in the participants' discussion.

) Users: Several types of users that have been discussed before can participate in JAD sessions according to their respective

quirements. Normally, the manager makes the decision on issues being discussed.

) Technical Staff: Besides handling the tools, hardware and software in JAD, they are also required to explain the detailed

pects of the technical system.

) System Development Team: This includes the analyst and user experts. They help in discussions, clarification, model building

cumenting the result of discussions, and ensuring that system requirements are defined clearly. They also ensure that JAD

ssion objectives are met.

) Business Process Re-Engineering (BPR): Process of re-thinking and re-designing the business process to achieve dramatic

improvement in terms of cost, quality and services (Hammer et al, 1993). Eg. A credit checking process that took six daysbefore can now be reduced to four hours only.

) Identifying Processes Needed in BPR: The process that needs to be changed must be understood before hand. Prior to that

u need to understand which process represents the key business process of the organisation.

) Key Business Process is a group of activities (that can be measured) that produces certain outputs for the customers or for a

rtain market. It focuses on products or services and customers of the organisation.

) The main tasks in BPR is to understand all activities in the key business process, and then to change the sequence or the

ructure of activities in order to upgrade quality, speed and customer satisfaction radically.

) Use of Information Technology: After the key business process and its activities have been identified, information technolog

) is applied to upgrade the business process in a radical way.

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) Process ModellingProcess Modelling: A formal way of explaining how a system operates. It shows processes, activities, business functions and

ta flow among them.

b) Data flow diagrams (DFD): describes the entire system in the graphic form that is easily understood. DFD shows the main

components of a system with processes, data flows, data stores, and external entities. Two sections: i) Logical DFD:

Shows what processes are operating inside an

organisation without touching on how the processes are implemented.

Eg. Ticket booking process and a Ticket issuing process ii) Physical DFD:

Explains how the processes are actually implemented.

Eg. the ticket booking process via the telephone, and ticket printing from the computer system

c) DFD Symbols: Four symbols to represent:

i) Process: Refers to an activity, function, or task that is done to achieve organisational objectives whether directly or

indirectly. A process can be manual or computerised.

ii) Data Flow: Consists of data that is moving or flowing as input to

a process or as output from a process. iii) Data Store: is used

to show data at rest. It is a situation in which data is stored to

be used by processes inside a system, when needed.

iv) External Entity: Consists of individuals, institutions, units, departments, organisations or information systems that ar

present outside the system, but are interacting by giving input or getting output from the system.

d) DFD Rules: i) Process:

) Process cannot contain output only. Output cannot be produced withoutinput (otherwise its a Miracle).

) Process cannot have input only (otherwise its a Black Hole)

(3) Process needs to use suitable input to produce output (otherwise its a Grey Hole). ii) Data Flow:

) Links between process and a data-store has only one direction. Two directions only when a process is linked to a data store

r showing data being retrieved before being processed.


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) Branched data flow shows that data from the same source flow to several processes, data stores, or external entities.

) Several data flows being combined show that data from different sources flow into the same location.

) Data flowing out cannot flow back to the process that produces them.

There must be a process in between. iii) Data Store:

) Data cannot flow from one data store to another data store without going through a process.

) Data-store cannot be linked directly to an external entity via data flow.

There must be a process in between. iv) External Entity:

(3) External entity cannot be linked directly to another external entity via data flow, without being processed first.

b) Other General Guidelines in DFD: i) Input to a process is different from its output. ii) DFD symbols contain unique names

iii) Use a unique reference number.

c) Context Diagram: shows the boundary and scope of the system, and how the system interacts with the external

environment. Context means the context in which the system sits.

d) Level-0 DFD: As context diagram, Level-0 DFD also shows the entire system components in one diagram. The objective

now is to show the main system processes only. i) Consistency: Every input and output data-flow at a higher level of DF

is retained at the lower levels to ensure that the diagrams are consistent and balanced.

e) Lower Levels DFD: The processes inside Level-0 Diagram are further decomposed into sub-processes of greater detail in

the next level of DFD, i.e. Level-1 Diagram. Processes in Level-1 Diagram are labelled with a kind of numbering -e.g. for


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process 1, it is now labelled as 1.1, 1.2, 1.3 and so on; while for process 2, it is

labelled as 2.1, 2.2, 2.3 and so on; and similarly for process 3, 4, etc.

i) Primitive Functions: Simplest processes which cannot be further decomposed into sub-processes, where we stop

detailing the DFD. Eg. Print Report, Record Booking, and Calculate Bill.

f) Two approaches in drawing a DFD:

i) Top-Down Approach in which the Context Diagram is drawn first, followed by Level-0 Diagram, Level-1 Diagram, until

you reach the Primitive DFD diagrams.

ii) Bottom-Up Approach in which the primitive functions are identified first, a combination of these primitive functions

forms the lowest level DFD, called the Primitive DFD. This is followed by DFD at higher levels until you reach the

Context Diagram.


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g) Process Descriptions: Would document the primitive functions. 3 ways: i) Structured English: Explains the logical process

by using simple sentences in English language. ii) Decision Table: Shows a logical structure consisting of a combination o

all process conditions and actions. iii) Decision Tree: Shows a logical structure, which appears like a tree. Beginning with

root and stem on the left, it

expands into branches and leaves towards the right.

h) Data Flow Description: By listing the data elements contained inside it, or by using algebraic symbols to describe data

structure that are more complex. Eg. Data flow "Student" contains data elements like student name, address and field

of study.i) Data Elements Description: Can be described by listing their types, length, and the meaning of the data concerned. Data

Store Description: Normally, data store is not described anymore, because data store inside a DFD represents data entit

inside ERD. If DFD is not linked to ERD, then data store is defined as a collection of data elements, similar to the

description of data flows.

6) Design Phase a) During the initial part of the design phase, the project group changes the logical diagrams of theanalysis phase into the physical diagrams that explain how the system will be built. b) Three approaches in creating a new

system: i) Custom in-house application system development: Allows the development to become more flexible and creativ

in solving business problems.

) In-house system development will assist in:

) Increasing the technical skills and knowledge of the developers who work together with the business users in the company;

) Understanding of business development that will make them more skilful in organising the information system requirement

d strategy; and

) Projects that use the same technology by making them easier to develop in future.

) In-house system development has a high risk because:

) No guarantee that the project would be successful;

) Developers may get involved in other projects too;

) Technical incompetence can slow down system development; and (d) Business users have no patience to wait for a long

velopment time. ii) Buying an application package and customising it

) Buying a software package is a wise decision because:

) Programs have been created, tested, and proven;

) Purchased application packages can be installed in a short period compared with custom system development; and

) A application package includes expertise and distribution from the supplier that created the software.

) Problems needed to be accepted after buying:

) You need to accept the functions provided by the system;

) The package normally does not provide all the company's needs; and

) The package that has a big scope can lead to changes in business functions. The scenario that allows technology to change

ur business functions may endanger the business industry.

) System Integration: Refers to the process of developing a new system by integrating or combining a software package, an

isting legacy system, and a new software.

) Outsourcing: Pay an external suppliers or service providers to develop the system, requires little in-house resources.

) Advantages:

) Those parties may have a lot of experience in technology

) or may have a lot of resources like programming experience.) Things to be observed if Outsourcing is Chosen:

) Company's confidential information may leak out,

) Control over future development may be lost;

) In-house development skills cannot be upgraded; and

) Development skills go to other parties.

) Steps to reduce risk of Outsourcing:

) Identify your project requirements completely. Do not outsource something that you do not understand at all.

) Choose your suppliers and developers carefully, and check their service records to see proofs of the system and the

chnology that you need.

) Types of Contracts:

) Time and Expenses Agreement: This type is very flexible because you agree to pay for the time and expenses incurred to


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mplete the job. However, this agreement can lead to a high cost, and can exceed estimated cost.

) Added Value Contract: This contract appears to be the most popular. The contractor receives a percentage of the added

lue after the system has been completed. You have a small risk here, but you need to share the benefits after the system is

plemented.

) Fixed-Price Contract: This means you do not have to pay beyond the estimated cost. If the contractor spends more than the

reed cost, he needs to bear the cost. So the contractor will fix the needs clearly. Any change or addition is difficult to entertain

)

uidelines to Outsourcing

) Ensure that communication between you and the outsourcer (contractor) is always active.

) Define and balance up the requirements before signing the contract.

) Be of the view that outsourcing is a form of partnership.

) Select the supplier, developer, or service provider with care.

) Assign someone to manage the relationship.

) Do not outsource something that you do not understand.

) Emphasise flexible requirements, long-term relationships, and short term contracts.

Factors to Consider before choosing a business strategy (Choice of Design Strategies)

) Alternatives Matrix: Used to organise advantages and disadvantages of the design alternatives so that the best solution can

be chosen. It is a grid containing technical, financial, and organisational feasibility for each candidate system. It combines a

number of feasibility analyses into a matrix so that alternatives can be compared easily.

Request For Proposal (RFP): Contains a proposed document for getting alternative solutions from development suppliers,

or service providers. Basically, RFP explains the system that you are trying to develop and the criteria that you use to

select a system.

i) Basic information to be contained in RFP:

) Explanation of the system needed;

) Specific technical requirements or situation;

) Evaluation criteria;) Instructions on how to give feedbacks; and

) Schedules required.

Steps in Creating a Physical DFD: i) Add implementation reference: Use existing logical DFD; place the direction of data store

ta flows, and processes that will be implemented inside opening statement below each component. ii) Sketch the

an-machine boundary: Sketch the boundary line that separates the system being automated from the manual section. iii) Add

ta stores, data flows, and processes of related system: Add data stores, data flows, and processes (of

related system) to the model. These are components that are less involved with the business process. iv) Update data

elements inside data flows: Update data flows for entering data elements of the related system. v) Update metadata

inside CASE (computer-aided software engineering) repository:Update metadata inside CASE repository for entering the

physical characteristics.

Needs When to use Custom

Development

When to use a

Software Package

When to use Outsourcing

Business Unique business

requirements.

Normal business

requirments.

Requirements are not important to

the business.

In-House Skills In-house technical and

functional experience is

present.

In-house functional

experience is present.

In-house functional and technical

experience is absent.

Project Skills There is a need for building

in-house skills.

Skills are not strategic. Decision to outsource is a strategic

decision.

Project

Management

There is a very experienced

project manager and a

proven methodology.

There is a project

manager who can

coordinate suppliers.

There is a project manager in a

highly skilled organisation and is

suitable with the scope of

outsourcing agreement.

Time-Frame Time frame is flexible. Time frame is short. Time frame is short and flexible.

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