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BCS – Certificate in IT
Study note for students
SOFTWARE DEVELOPMENT
Software and Software Development
 What is Software?
Software is…
...

 Data structures that enables the programs to adequately manipulate
information
...

From the above definitions it is important to realize that software is not only the
“Executable” programs but includes several other elements that support them in their
operation
...


Types Of Software Products
Software products fall into 2 categories:
 Generic Products(Off the shelf Products)
These are the information systems which are produced by a development
organization and sold on the open market to any customer who are interested to
buy them
...
The software
house develops the software especially for a special customer
...
Less Expensive (cost divided among

Bespoke Products
1
...

2
...


2
...


3
...


3
...


4
...


4
...


5
...
Completely Satisfied
...


Other Classification of Software
 System software :
System software is directly controlling the hardware resources and supports the
operation of application software
...

They can be categorizing as follows
...
For the effective control of the software development process it is
essential to have a phased development strategy
...

The software development process model is also called as “Software Development Life
Cycle (SDLC)” As the process is repeated when software need to be changed as long as the
software is in use
...


Software Process Models
1
...
Rapid Application Model(RAD)
3
...
It offered a means of making the development process more visible
...
output of the one
stage should be input in another stage
...


Main Stages of Waterfall Model:
1)
2)
3)
4)
5)
6)

Requirement gathering and analysis
System and software design
Coding
Testing
Deployment
Maintenance

Requirement gathering and analysis
The system services, limitations (constrains) and goals are established by consultation with
system users
...
It
establishes overall system architecture
...


Coding (Implementation)
In this stage chosen programing language will be used to make program alive
...


Testing
Testing is an important portion of SDLC
...


Install(Deployment)
After completing all the testing system can be implement in client‟s environment
...


Maintenance
After completing the software it should maintain by the software house
...
This is the longest phase in SDLC
...

Process is more visible
...

Less risks
...

Can manage any kind of systems
Ex: Life Critical Systems

Disadvantages of Waterfall Model






Changes cannot be accepted within the stages
...

Time consuming
...

Developers should wait until end of one stage
...

That emphasis on exactly short development cycle (short term project)
...

If requirements are well understood and project scope is constrained
...

(60-90 days)

RAD has main stages as follows:
1
...

3
...

5
...

Need more developers(costly)
Life critical systems cannot implement
Poor user involvement
Less documentation

Prototyping
 What is prototype?
Prototyping is a process that enables the developers to create a model of the software
to be built
...
It is almost important to predict how a system build affect the working
practices
...

The objective prototyping should be main explicit from the start of the process
...


Types of Prototype
There are many types of prototype available but in general we concerned two of them
...
Throw away prototyping:
This approach extends the requirement analysis process with the intension of
reducing overall life cycle cost
...
After getting
requirements given example software (prototype)is throw away and it is not used as
a basis for further system development
...


Throw away Diagram

Outline
requirements

Develop
Prototype

Develop
Software

Evaluate
Prototype

Validate
System

Specify System

Delivered
Software System

Advantages of Throw away





Can identify requirement using real software model
More user involvement
Requirement changes can be accepted up to some level
User can see working software in early stages of SDLC
...
It is costly time wasting
 More user involvement can be lead to scope creek
 From beginning of requirement gathering should bear more cost

2
...
In this approach the
prototyping and production process are merge, it means that the prototype graduate
evolve to the final product
...


Evolutionary Diagram

Develop abstract
specification

Deliver system

Build prototype
system

System
adequate?

Use prototype
system

Advantages of Evolutionary Prototyping
 Can be used with unclear requirements
 Requirements can be easily changed
 Active user involvement

Disadvantages of Evolutionary Prototyping
 Process is over flexible
 Poor system structure
 Less documentation

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