2. SYSTEM LIFE CYCLE
System life cycle is an organizational process of
developing and maintaining systems. It helps in
establishing a system project plan, because it gives
overall list of processes and sub-processes required
for developing a system.
System development life cycle means combination of
various activities.
In other words we can say that various activities put
together are referred as system development life cycle.
In the System Analysis and Design terminology, the
system development life cycle also means software
development life cycle.
3. Following are the different phases of system
development life cycle:
•
System investigation
•
Feasibility study
•
System analysis
•
System design
•
Coding
•
Testing
•
Implementation
•
Maintenance
4. PHASES OF SDLC
SYSTEM INVESTIGATION
Feasibility study
Maintenance
System Analysis
Implementation SDLC
System Design
Testing
Coding
5. S Y S T E M I NV E S T I GA T I ON
System investigation is the first stage of
system development life cycle.
This phase is intended to be quick .
6. Business Community 1.List Problems,
Steering Community oppurtunities
and directives
Data Store
Present the 2.Determine scope
Project Plan
Project is
4.Plan the worthy 3.Assess project
Project worth
7. 1.To determine whether a business problem or
opportunity exists.
This involves identify the problem, estabilish an initial
baseline of the problems,oppurtunities and
directives that triggered the project.
Listing constraints such as project
deadlines,maximum budget,general technology.
System analyst or project manager leads this task.
8. 2. Define the scope of the project.
Scope defines the boundary of the project and can
be easily defined within the context of your
information system building blocks.
Scope can be described in terms of:
What types of data describe the system being
studied?
What business processes are included in the
system?
How must the system interface with the users ?
9. 3. Assess project worth
Is this project worth looking at?
Will it solve the problems?
Is this beneficiary?
4.Plan the Project
The initial project plan should consists of atleast the
following:
A preliminary master plan that includes schedule and
resource assignments for the entire project.This plan
will be updated at the end of each phase of the
project.This is sometimes called a baseline plan.
10. A detailed plan and schedule for completing the next
phase of the project.
The task is responsibility of the project manager.
5.Present the project and plan.
Present the estimated project plan to the steering
body for approval.
A steering body is a committee of executive business
and system managers that studies and prioritizes
competing project proposals to determine which
project will the most value to the organisation and
thus should be approved for continued system
development.
11. FEASIBILITY STUDY
The goal of feasibility study is to evaluate
alternate systems and to propose the most
feasible and desirable system for
development.
Feasibility Study is essential to evaluate cost
& benefits of the proposed system
12. Types of feasibility study
1) Technical Feasibility.
2) Operational Feasibility.
3) Economical Feasibility.
4) Motivational Feasibility
5) Schedule Feasibility
13. Technical Feasibility
Following things should be considered:
Determine available hardware.
Determine available computer with configuration.
Determine available software.
Find out technical feasibility required for proposed
system
1) Mention new hardware requirements of proposed
system.
2) Mention Computer with new configuration
requirements of proposed system.
3) Mentions New software requirements of the proposed
system.
14. Operational Feasibility
It finds whether the operations of proposed system is
easy or not as compare to existing system.
It find out whether the user or customer of the
system requires extra training or not
System should provide right & accurate information
to user or customer at right place as well as at right
time.
15. Economical Feasibility
Whether expected cost savings, increased
revenue, increased profits and other type of
benefits will exceed the cost of developing
and operating a proposed system.
16. Motivational Feasibility
The probability that the organisation is
sufficiently motivated to support the
development and implementation of the
application with necessary user
participation,resources,training time etc.
18. Cost / Benefit Analysis
Feasibility studies involve cost / benefit
analysis.
If costs and benefits are quantified, they are
called tangible.
If not they are intangible.
Tangible benefits are favourable results.
Intangible benefits are harder to estimate.
Such benefits are better customer service or
faster and more accurate information for
management to fall into this category.
19. TANGIBLE BENEFITS
1. Increase in sales or profits.
2. Decrease in information processing costs.
3.Decrease in operating costs.
4. Decrease in required investment.
5. Increased operational ability and efficiency.
20. INTANGIBLE BENEFITS
1. New or improved information availability.
2. Improved abilities in computation and
analysis.
3. Improved customer service.
4. Improved employee morale.
5. Improved management decision making.
6. Improved competitive position.
7. Improved business and community image.
21. SYSTEM ANALYSIS
Involves a detailed study of:
1.The information needs of the organisation
and end users.
2. The activities,resources and products of
any present information.
3. The information system capabilities
required to meet the information needs and
those of other end users.
22. 1.Organisational Analysis
To know something about the organisation,its
management,structure,its people, its
business activities, the environmental
systems it must deal with and its current
information systems.
Conduct a detailed study of specific end user
department that will be affected by the new
or improved information system being
proposed.
23. 2. Analysis of present system
Before designing a new system , it is
important to study the system that will be
improved or replaced(if there is one).
Analyse how this system uses hardware, ,
software, network, and people resources to
convert data resources such as transactions
data into information products, such as
reports and displays.
Also note how the information system
activities of input,output,storage,control are
accomplished.
24. 3.Functional Requirement Analysis
To determine what type of information you
require,what its format,volume, and
frequency should be and what response
times are necessary.
To determine the information processing
capabilities required for each system activity
to meet these information needs.
Goal is to determine what should be done.
Try to develop the functional requirements
like:
25. a . User Interface requirements : The input
output needs of end users that must be
supported by the information system,
including sources, formats,content, volume,
and frequency of each type of input and
output.
b. Processing requirements : Activities
required to convert input to output. Includes
calculations,decision rules, and other
processing operations, and capacity .Also
find throughput,turnaround time and
response time needed for processing
activities.
26. c. Storage requirements : Organisation
content and size of databases, types and
frequency of updating and retrieving
records.
d. Control requirements :Accuracy,validity,
safety, security and adaptability
requirements for system output, processing,
input and storage functions.
27. SYSTEM DESIGN
System analysis describes what a system
should do to meet the information needs of
users.
System design specifies how the system will
accomplish this objective.
System design consists of design activities
that produce system specifications satisfying
the functional requirements developed in the
system analysis stage.
28. Elements of system design
Data Flow : The movement of data in and
out of the system.
Data Stores : Temporary or permanent
collection of data.
Process : Activities to accept manipulate
and deliver data and information.
Procedures : Methods and routines for using
the information systems.
Controls : These are standards and
guidelines for determining the activities.
Roles : The reponsibilities of all persons.
29. System design focuses on 3
activities
USER
DATA PROCESS
INTERFACE
DESIGN DESIGN
DESIGN
Screen,form Data element Program
Reports, Structure and
Dialog designs design structure
design
30. User Interface Design
Focuses on designing the interaction between end
users and computer systems
Designers concentrate on input/output methods and
the conversion of data and information between
human readable and machine readable forms.
Prototyping process in which user interface methods
are designed and modified with feedback from
end users.
It produces detailed specification for information
products such as display screens,interactive user/
computer dialogues,audio responses,forms,
documents and reports
31. Data Design
Focuses on design of the structure of
databases and files to be used by a
proposed system.
Data design produces a data dictionary which
includes
a.The attributes or characteristics of the
entities (objects,people,places,events) about
which the proposed system needs to
maintain information.
b. The relationships these entities have to
each other.
32. c. The specific data elements(dbs,files,
records) that need to maintained for each
entity tracked by the system.
d. The integrity rules that govern how each
data element is specified and used in the
system.
33. Process Design
Focuses on the design of software resources
ie, programs and procedures needed by the
proposed system.
Process design produces detailed program
specifications and procedures needed to
meet the user interface and data design
specifications that are developed.
Process design must also produce
specifications that meet the functional
control and performance requirements
developed in the analysis stage.
34. System Specifications
The design of user interface methods and
products , database structures and
processing and control procedures results
in hardware,software, network, data and
personnel specifications for a proposed
system.
User interface specification: The content ,
format, and sequence of user interface
products, and methods such as display
screens, interactive dialogs, audio
responses, forms, documents and reports.
35. Database Specifications : Content, structure,
distribution and access, response,
maintenance, and retention of db.
Software Specifications: The required s/w
package or programming specifications of
the proposed system including performance
and control specifications.
Hardware and network Specifications:The
physical and performance characteristics of
the equipment and networks required by the
proposed system..
Personnel Specification: Job description of
persons who will operate the system.
36. Design of output
Output generally refers to the results and
information that are generated by the
system.
When designing output, system analyst must
accomplish the following:
1. Determine what information to present.
2. Select the output medium.
3. Arrange the presentation of information.
4. Decide how to distribute the output to intend
recipients.
37. What factors contribute to high
quality, useable
information(output)?
Timeliness - is it available in time?
Relevance - is it helpful?
Accuracy - is it error-free?
Accessibility - how easy is it to use?
Useability - is it in an acceptable format?
39. Output Objectives
Convey information about past activities,
current status, or projections of the future.
Signal important events, oppurtunities,
problems or warnings.
Confirm an action.
40. Design of input
System analyst decide the following input
design details:
- Input data
- Medium of use.
- Arrangement of data
- Guidelines for users.
- Data items needing validation and steps
to follow when errors occur.
41. Objectives of input design
- Controlling amount of input.
- Avoiding delay.
- Avoiding errors in data.
- Avoiding extra steps.
- Keeping the process simple.
42. Design of Files
It includes decisions about the nature and
content of the file itself such as whether it is
to be used for storing transactions details,
historical data or reference information.
Which data items to include in a record form
within the file?
Length of each record based on the
characteristics of the data items on which it
is based.
The arrangement of records in the file.
