An Introduction to Software Development Life Cycle

1. System Development Life Cycle
(SDLC)
Lecturer in Computer Science
University of Education, Okara Campus
inam@ue.edu.pk, organizer@dfd-charity.com, inam.bth@gmail.com
University of Education Okara
Campus
Inam Ul-Haq
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2. Beginning of a System Development
History: emerges as Software Engineering in 1960’s in a conference to solve a problem
called “software crisis”.
Purpose: Design & Development of high-quality software
System Development is having two major component in it
• System Analysis – Analysis of current system for Problems & Demerits in it and
Additional requirements in new system
• System Design – Process of planning new system which will replace the old one
Documentation: It is an essential component of software because it is not possible to
understand different aspects of large programs without documentation.
It has been observed that efforts required to write documentation of large system is as
great as efforts required to develop systems.
Software Engineering: An engineering discipline concerned with the efficient and
economical development of large software systems.
• 4th generation of Software Engineering in progress.
• Software process life cycle or System Life cycle (SDLC)
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System or Software: Programs + Documentation required to develop, install, use and
maintain software
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3. System Development Life Cycle
In an organization System Development can be achieved by following steps:
2. Requirements analysis or system analysis
3. Design of System
4. Development of Software
5. System Testing
6. Implementation and Maintenance
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1. Preliminary Investigation
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4. Preliminary Investigation
1. Preliminary Investigation
The objective of this activity is to review all requests and identify those proposals that
are most beneficial to the organization. But this should be noted that this is neither a
designed study nor it includes collection of details to completely describe the
business system.
Preliminary Investigation can be achieved in following steps:
• Request Clarification
• Feasibility study
• Estimating Costs and Benefits
• Request Approvals
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Whatever may be the reason of a request submitted by the Users or Managers to the
IS department, a system analyst is assigned to make a preliminary investigation.
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5. Preliminary Investigation
Request Clarification
Defining the Scope and Objective of Request:
•
•
•
As mentioned in the objectives of System development objective earlier, an analyst
has to define for which objective a request for development is submitted.
•
This is collection of data / inputs by:
•
•
•
Reviewing employees workloads etc.
Conducting interviews of User, Supervisory Personal and Managers
Identify Viable Option:
•
Analyst has to identify the viable option by applying his common sense and
intuitions on his investigation
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Conducting the Investigation
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6. Preliminary Investigation
Feasibility (Possibility) Study
•
•
•
•
Technical Feasibility: Hardware and software availability, Technical Guarantee of
Accuracy, Reliability, Easy to Access, Data security, technical capacity to hold data and
future expansion.
Economical Feasibility: Evaluation of cost & Benefits expected.
Operational Feasibility: Finding views of workers, employees, customers & suppliers
about the use of new system.
Schedule Feasibility: Estimation of time to take new system to become operational.
Legal feasibility: Testing whether new system will comply financial reporting
requirements & Company’s contractual obligations.
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•
Evaluation of alternative systems through cost and benefit analysis:
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•
Request Approval: Based on the Observation and Findings of the Analyst, selected
requests are put up for the approval of management

7. Requirement Analysis & System Analysis
2. Requirement Analysis
Software Process: or Software Life Cycle consists of discrete no. of steps required to
complete a software. A final model of software is still a topic of research. However
few models are available:
• Waterfall Model
• Prototyping Model
• Rapid Application Development (RAD)
This phase of System Development is being completed in following step:
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After Preliminary Investigation, study in depth the Present and Proposed New
System. This is the study of weakness & Problems in the present system and
management requirements of new system.
 Collection of data and facts
 Analysis of Present System, Analysis of Proposed system
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8. Requirement Analysis & System Analysis
Collection of Data & Facts
•
Documents: This includes the Manuals, diagrams, forms, organizational charts etc. It
should be ensured that all documents are accurate & up to date
•
Questionnaires: These are skillfully drafted group of standard question which can be
given to all personal and can be analyze quickly.
•
•
Interviews: To get a complete picture of problems and opportunities.
Observation: Surprise Visit of users work palace to get a clear picture of user’s
environment.
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Every system is built to meets some set of needs and to assess these needs, the
analyst often interact extensively with the people, who will be benefited from the
system In order to determine the requirement of those peoples he can use following
facts finding techniques:
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9. Requirement Analysis & System Analysis
Analysis of Present System
Detailed investigation of the present system involves collecting, organizing and
evaluating facts about the present system and the environment in which it operates by
studying following areas in depth:
Review of Historical Aspects of organization

Analyze Present inputs to the system

Review of all data file maintained irrespective of online or offline

Review methods, procedures & data communications

Analyze Present outputs of system

Review internal controls

Model the existing physical system and logical system

Undertake overall analysis of present system
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
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10. Requirement Analysis & System Analysis
Analysis of Proposed System
After each functional area of present system is defined the purposed system specification
must be defined.
These specification will be based on the strength and weakness of present system.
•
Output / Reports
•
Maintenance of Database
•
Data Inputting Process
•
Methods and Procedures to show the relationship between Input and Output
•
Work volume including peak period work volume
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System Specification which should be in conformity with the Project Objective and Areas
Covered should be following:
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11. System Design
1. Software prototyping, refers to the activity of creating prototypes of software applications,
i.e., incomplete versions of the software program being developed. It is an activity that can
occur in software development and is comparable to prototyping as known from other fields,
such as mechanical engineering or manufacturing.
A prototype typically simulates only a few aspects of, and may be completely different from,
the final product.
2. Rapid application development (RAD) is a software development methodology that uses
minimal planning in favor of rapid prototyping. The "planning" of software developed using
RAD is interleaved with writing the software itself. The lack of extensive pre-planning generally
allows software to be written much faster, and makes it easier to change requirements.
3. The spiral model is a risk-driven process model generator for software projects. Based on
the unique risk patterns of a given project, the spiral model guides a team to adopt elements
of one or more process models, such as incremental, waterfall, or evolutionary prototyping.
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3. System Design (Contt.)
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12. System Design
3. System Design
4. Scrum is an iterative and incremental Agile software development framework for managing
software projects and product or application development. Its focus is on "a flexible,
holistic product development strategy where a development team works as a unit to reach
a common goal" as opposed to a "traditional, sequential approach". Scrum enables the
creation of self-organizing teams by encouraging co-location of all team members, and
verbal communication among all team members and disciplines in the project.
5. Joint application design (JAD) is a process used in the prototyping life cycle area of
the Dynamic Systems Development Method (DSDM) to collect business requirements
while developing new information systems for a company. "The JAD process also includes
approaches for enhancing user participation, expediting development, and improving the
quality of specifications." It consists of a workshop where “knowledge workers and IT
specialists meet, sometimes for several days, to define and review the business
requirements for the system.” The attendees include high level management officials who
will ensure the product provides the needed reports and information at the end. This acts
as “a management process which allows Corporate Information Services (IS) departments
to work more effectively with users in a shorter time frame
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There are common five models for software development.
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13. University of Education Okara
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Prototyping Model
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14. University of Education Okara
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Waterfall Model
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15. University of Education Okara
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Spiral Model
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16. University of Education Okara
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RAD Model
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17. University of Education Okara
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JAD Model
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18. System Acquisition & Development
4. Selection of Software Model
Selection of a perfect Software for organization is totally depends on the followings:
• Low Risk of Quality: Software should be properly tested by the manufacturer for the
quality otherwise organization has to spend its precious time on quality assurance.
• Low Risk of Cost: The cost and benefit analysis will give us the perfect cost, which
organization can bear for acquiring the given software.
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• Rapid Implementation: Whether software can be implemented quickly and put on
use ASAP. This characteristic will not be there if software is to be developed, hence
that will take long time.
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19. System Testing
5. System Testing
This is Performing Parallel Operation and get the following done to analyze the
operational implementation feasibility:
 Processing of Test Data with the new system and take all outputs which can be
possible.
 Checking result of all system with the results of the same data in the current system
for the accuracy and error in the processing.
 Review result with future users, operational and support personal:
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 Preparation realistic data based on the actual working data of the organization. It
may be based on the Historical data of the organization.
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20. Implementation & Maintenance
6. Implementation & Maintenance
As the final Phase of the System Development it gives the results of the whole
process and handover the new system to end users.
To complete this phase a developer has to complete the following functions
successfully:
• Equipment Installation
• Training Personnel:
• Conversion Procedure:
• Post Implementation Evaluation (Feedback)
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This also includes the overall review of the development process for its leakages and
errors in it.
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21. Implementation & Maintenance
Equipment Installation
This includes following functions:
• Equipment Installation: Assembling and commissioning of the equipments
(hardware) and installation of software
• Equipment Checkout: Organize test runs of the system with sample actual data and
thereafter if it performs satisfactory than with the live actual data.
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• Site Preparation: Preparing the site for installation and mobilizing all required
equipments and personnel at the site.
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22. Implementation & Maintenance
Training Personnel
If there are deficiencies in Training, these may translate into reduction in user
Productivity Levels
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Since user are not familiar with the New System, System Development Process
includes training of • System Operators: IT personnel who will handle the system maintenance in the
future.
• Users (Operators): The final user who will work on the system.
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23. Implementation & Maintenance
Post Implementation Evaluation (Feedback)
Analysis of Satisfaction of Users or checking whether system is Operating Properly
or whether Objectives of System Development is achieved or not, is the most
important function in whole System Development process.
Post Implementation Evaluation includes following area:

Development Evaluation: Check whether development was done within
schedule and budgets.

Operation Evaluation: Check whether system is capable for handling the
duties and objective of development is achieved

Information Evaluation: Check Satisfaction of users etc.
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This is also important for development of new system in future since each
development gives some experiences and lists some things to be taken care off.
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24. References
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• http://en.wikipedia.org/wiki/Software_development_process
• http://en.wikipedia.org/wiki/Systems_development_life-cycle
• http://www.mks.com/solutions/discipline/software-development-life-cycle-sdlc-systemdevelopment
• http://en.wikipedia.org/wiki/Software_prototyping
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