This document provides an overview of system development and information systems. It discusses reasons for creating or modifying systems, such as to correct problems or improve existing systems. It then describes the system development life cycle process, which involves six phases: preliminary investigation, system analysis, system design, system development, system implementation, and system operation and maintenance. It also discusses topics such as the roles of systems analysts, feasibility analysis, different approaches to system development, and implementation considerations.

1. SYSTEM DEVELOPMENT

2. What are some reasons to create or
modify an information system?
To correct problem To improve
in existing system existing system
Competition can
Outside group may lead to change
mandate change

3. System Development
 Systems development is the process
of defining, designing, testing, and
implementing a new software
application or program. It could
include the internal development of
customized systems, the creation of
database systems, or the acquisition
of third party developed software.

4. System Development
Life Cycle (SDLC)
 Six Phases of the System Development
Life Cycle
 Preliminary Investigation
◦ Assesses feasibility and practicality of system
 System Analysis
◦ Study old system and identify new
requirements
◦ Defines system from user's view
 System Design
◦ Design new/alternative system
◦ Defines system from technical view

5.  System Development
◦ New hardware and software is
acquired, developed, and tested
 System Implementation
◦ System installation and training
 System Operation & Maintenance
◦ Daily operation
◦ Periodic evaluation and updating

6. Preliminary
Investigation
System
System Operation Analysis
& Maintenance
System System
Implementation
n Design
System
Development

7. Who is a systems analyst?
 Responsible for designing and developing
informationsystem
 Liaison between users and IT
professionals

8.  What is the project team?
 Formed to work on project from
beginning to end
 Consists of users, systems
analyst, and other IT professionals
 Project leader—one member of the
team who
manages and controls project budget
and schedule

9.  What is feasibility?
Schedule feasibility
Measure of
how suitable Four feasibility
system tests:
development Operational
will be to the feasibility
company
Economic feasibility (also called cost/benefit
feasibility)

10. Approaches to Systems
Development
 Process-Oriented Approach
◦ Focus is on flow, use and transformation of data
in an information system
◦ Involves creating graphical representations such
as data flow diagrams and charts
◦ Data are tracked from sources, through
intermediate steps and to final destinations

11. Approaches to Systems
Development
 Data-Oriented Approach
◦ Depicts ideal organization of
data, independent of where and how data
are used
◦ Data model describes kinds of data and
business relationships among the data
◦ Business rules depict how organization
captures and processes the data

12. Alternative
ApproachesPrototyping
Approach
 The prototyping approach is used in the
requirement gathering and in the analysis phase
to capture the exact requirement of the proposed
system. After the requirements are frozen, the
remaining phases of the development process
needs to be executed to complete the
development of the software system.
 An e-commerce website, such as shopping site is
an example where you can implement the
prototyping approach. You can develop the
prototype of the various web pages of the
shopping site such as catalogue page, product
order page etc., and present it to the customer
for approval. If the customer approves the
prototype of the site, requirements are states
again and the design of the web site is initiated.

13.  The prototype is a working system developed to
test the behaviour of new system.The prototype
generates output from input of data fed to it and
this output is evaluated to know knoe possible
enhancements to the prototype. Its required
while:
 Building an experimental system quickly and
cheaply
 Unclear user requirements
 1.User involvement
 2.Fast
 1.Poor system quality
 2.Lack of standard

14. Need for prototyping
 Enables us to explore the problem
space with the stakeholders.
 A vehicle for you to communicate the
possible UI design(s) of your system.
 A potential foundation from which to
continue developing the system

15. Advantages:
 * This type of approach of developing the software is
used for non-IT-literate people. They usually are not
good at specifying their requirements, nor can tell
properly about what they expect from the software.

* It reduces risk of failure, as potential risks can be
identified early and mitigation steps can be taken.

* Iteration between development team and client
provides a very good and conductive environment
during project.

16. Disadvantages of Prototyping
Model:
 Prototyping is usually done at the cost of
the developer. So it should be done using
minimal resources.
* It is a slow process.
*Too much involvement of client, is not
always preferred by the developer.
*Too many changes can disturb the rhythm
of the development team.

17. Application Software Packages
Prewritten, pre-coded application
software, commercially available for sale
or lease
 Geared to common requirements (sig
nificant few; Canned functions) Accounts
receivable; Bond & stock management;
Computer-aided design (CAD) ;
document imaging; E- mail;
Enterprise.Resource planning (ERP);
Groupware; Health care;
Hotel.Management; Internet telephone;
Inventory control; Job costing.

18. Enduser development
 Building the system by end-users with
little or no formal technical assistance
 When? ForPersonal & small
applications
 WHY?
 1.No misunderstanding
 2.Fast

19.  End-users develop information system
themselves, with little help from
technical specialists; Using 4th
generation tools
Strengths:
 Improved requirements determination
 Increased user involvement &
satisfaction

20. Weaknesses:
 Relatively inefficient
 Slow transaction processing
 May carry high/hidden cost

21. Outsourcing
 Using an external vendor to develop
or operate an organization's ISs
 Mission is non-critical applications
 1.Reduce costs
 2.Predictability
 1.Risky
 2.Loss of control

22. Contracting:
 Computer center operations
 Telecommunications networks

23. Structured methodology
(“Waterfall”)

24. ADVANTAGES
A waterfall model helps find
problems earlier on which can
cost a business less than if it
was found later on.
Requirements will be set and
these wouldn't be changed.
As everything is documented a
new team member can easily
understand what's to be done.
Implementers have to follow
the design accurately

25. DISADVANTAGES
 If requirements may change the
Waterfall model may not work.
 Many believe it is impossible to make
one stage of the projects life cycle
perfect.
 Difficult to estimate time and cost for
each stage of the development
process.
 Constant testing of the design is
needed.

26. System analysis
 Systems
◦ System is an interrelated set of components, with
identifiable boundary, working together for some
purpose
 A system has nine characteristics:
◦ Components----------------------Subsystems
◦ Interrelated components
◦ A boundary
◦ A purpose
◦ An environment
◦ Interfaces
◦ Input
◦ Output
◦ Constraints

27. System Analysis
 Systems analysis is a process of
collecting factual data, understand the
processes involved, identifying problems
and recommending feasible suggestions
for improving the system functioning.
This involves studying the business
processes, gathering operational
data, understand the information
flow, finding out bottlenecks and evolving
solutions for overcoming the
weaknesses of the system so as
toachieve the organizational goals.

28. OBJECTIVES
 The major objectives of systems
analysis are to find answers for each
 business process: What is being
done, How is it being done, Who is
 doing it, When is he doing it, Why is it
being done and How can it be
 improved?

29. System Design
 Based on the user requirements and the
detailed analysis of the
 existing system, the new system must be
designed. This is the phase
 of system designing. It is the most crucial
phase in the developments of a system. The
logical system design arrived at as a result of
 systems analysis is converted into physical
system design. Normally,
 the design proceeds in two stages:
 Preliminary or General Design
 Structured or Detailed Design

30.  Preliminary or General Design: In the
preliminary or general design, the
features of the new system are
specified. The costs of implementing
these features and the benefits to be
derived are estimated.
 If the project is still considered to be
feasible, we move to the detailed
design stage.

31.  Structured or Detailed Design: In the
detailed design stage, computer
oriented work begins in earnest. At
this stage, the design of the system
becomes more structured. Structure
design is a blueprint of a computer
system.

32.  There are several tools and techniques
used for describing the system design of
the system. These tools and techniques
are:
 l Flowchart
 l Data flow diagram (DFD)
 l Data dictionary
 l Structured English
 l Decision table
 l Decision tree

33. steps
 The system design involves:
 i. Defining precisely the required system output
 ii. Determining the data requirement for producing the output
 iii. Determining the medium and format of files and databases
 iv. Devising processing methods and use of software to
produce
 output
 v. Determine the methods of data capture and data input
 vi. Designing Input forms
 vii. Designing Codification Schemes
 viii. Detailed manual procedures
 ix. Documenting the Design

34. SYSTEM IMPLEMENTATION
It is the process of carrying out the
operational plans developed as a part
of information system planning .
 Implementation includes all the
activities required to replace the old
system by the new system. . The
implementation process involves
acquisition of IS resources , testing
, documentation , installation and
conversion process.

35. STEPS
 Hiring and training the personnels
 Program development
 Site preparation
 Acquisition and installation of
hardware
 Software aquisition
 File conversion
 Documentation

36. FACTORS FOR SUCESSFUL
IMPLEMENTATION
 Involving users in project
implementation
 Setting up a cohesive project mgt for
implementation
 Using project mgt tools like , PERT
,CPM etc.
 Use of formal controltools to monitor
project implementation
 Overcoming user resistance

37. Causes
Lower user involvement in project
implementation
 Lack of commitment from top mgt for
the project
 Complexity of project
 Poor mgt of project implementation
process.

38.  INFORMATION SYSTEM AUDIT

39. Generally Accepted Auditing
Standards (GAAS)

40. External versus Internal Auditing
 External auditors represent the
interests of third party
stakeholders, while internal auditors
serve as an independent appraisal
function within the organization.
 Internal auditors often perform tasks
which can reduce external audit fees
and help to achieve audit efficiency
and reduce audit fees.

41. Elements of an Audit
 Systematic procedures are used
 Evidence is obtained
◦ tests of internal controls
◦ substantive tests
 Determination of materiality for
weaknesses found
 Prepare audit report & audit opinion

42. Phases of an IT Audit

43. COMPUTER NETWORKS
 A computer network, or simply
a network, is a collection of computers and
other hardware interconnected by
communication channels that allow sharing of
resources and information. Where at least
one process in one device is able to
send/receive data to/from at least one
process residing in a remote device, then the
two devices are said to be in a network. A
network is a group of devices connected to
each other.

44. Intranets and extranets
 Intranets and extranets are parts or extensions of a computer
network, usually a LAN.
 An intranet is a set of networks, using the Internet
Protocol and IP-based tools such as web browsers and file
transfer applications, that are under the control of a single
administrative entity. That administrative entity closes the
intranet to all but specific, authorized users. Most
commonly, an intranet is the internal network of an
organization. A large intranet will typically have at least one
web server to provide users with organizational information.
 An extranet is a network that is limited in scope to a single
organization or entity and also has limited connections to the
networks of one or more other usually, but not
necessarily, trusted organizations .Technically, an extranet
may also be categorized as a CAN, MAN, WAN, or other type
of network, although an extranet cannot consist of a single
LAN; it must have at least one connection with an external
network.

45. Network Devices
Wireles
s

47. Router, Switch, Hub, Modem,
 Routers are small physical devices that join
multiple networks together. Technically, a
router is a gateway device, meaning that it
connects two or more networks and that the
router operates at the network layer of
the OSI model.Home networks typically use a
wireless or wired Internet Protocol
(IP) router, IP being the most common OSI
network layer protocol. An IP router such as a
DSL or cable modembroadband router joins
the home's local area network (LAN) to
the wide-area network (WAN)of the Internet.

48.  A network switch is a small hardware
device that joins multiple computers together
within one local area network (LAN). Network
switches appear nearly identical to network
hubs, but a switch generally contains more
intelligence (and a slightly higher price tag)
than a hub. Unlike hubs, network switches
are capable of inspecting data packets as
they are received, determining the source
and destination device of each packet, and
forwarding them appropriately .

49. Hub
 Hub is used to create connections between
stations in a physical star topology. Hub is a
central n/w device that connects network
nodes. It is also referred as concentrators. It
enables central n/w management. It can have
multiple inputs & outputs all active at one
time. It Permits large numbers of computer to
be connected on a single or multiple LANs. It
enables high speed communication. Provide
connection for several different media types.
(Coaxial, fiber optic, twisted pair).

50.  Modem is a computer device that modulates
and demodulates data signals. It enables the
computer to transmit the data over the phone
line. The data over the telephone line is
transmitted in the analog form and when it
reaches at the computer at other end it must
be presented in the digital form so that
computer can understand it. The modem
takes the data and converts it in the readable
form for your computer i.e. digital
form. Modem IS used on dialup
networks convert data between the analog
form used on telephone lines and the digital
form used on computers.

51. TOPOLOGIES
 Incomputernetworking, topology refers
to the layout of connected devices.
 Network topologies are categorized
into the following basic types:
 bus
 ring
 star
 tree
 mesh

52. Bus Topology
 Bus networks (not to be confused with the
system bus of a computer) use a common
backbone to connect all devices. A single
cable, the backbone functions as a shared
communication medium that devices attach
or tap into with an interface connector. A
device wanting to communicate with another
device on the network sends a broadcast
message onto the wire that all other devices
see, but only the intended recipient actually
accepts and processes the message.

53. Ring Topology
 In a ring network, every device has
exactly two neighbors for communication
purposes. All messages travel through a
ring in the same direction (either
"clockwise" or "counterclockwise"). A
failure in any cable or device breaks the
loop and can take down the entire
network. THE ring network, topologies
are found in some office buildings or
school campuses.

54. Star Topology
 Many home networks use the star
topology. A star network features a
central connection point called a "hub
node" that may be a network
hub, switch orrouter. Compared to the
bus topology, a star network generally
requires more cable, but a failure in any
star network cable will only take down
one computer's network access and not
the entire LAN. (If the hub
fails, however, the entire network also
fails.)

55. Tree Topology
 Tree topologies integrate multiple star
topologies together onto a bus. In its
simplest form, only hub devices connect
directly to the tree bus, and each hub
functions as the root of a tree of devices.
This bus/star hybrid approach supports
future expandability of the network much
better than a bus (limited in the number
of devices due to the broadcast traffic it
generates) or a star (limited by the
number of hub connection points) alone.

56. Mesh topologies
 Mesh topologies involve the concept
of routes. Unlike each of the previous
topologies, messages sent on a mesh
network can take any of several
possible paths from source to
destination. (Recall that even in a
ring, although two cable paths
exist, messages can only travel in one
direction.) Some WANs, most notably
the Internet, employ mesh routing.

57. TYPES OF NETWORK
LAN
 WAN
 MAN

58.  SOCIAL & ETHICAL ISSUES