Software Design Tutorial

Software Design  Process is a process that implementing Software solutions to one or more set of problems. This Design process will help the programmer in software coding and implementation. It usually involves problem solving and and planning a software solution. Software Design is both a process and a model. The software Design process is a sequence of steps that enables the designer to describe all aspects of the software for building.

Software Design:

• Requirements analysis tells us what the software is supposed to do. The design specifies  how to do it.

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• What modules will be needed?

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• What does each one accomplish? 

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• What data does each one require?

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•  How will they interact?

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Software Design Process:

There are Two-stage activity in the Design Process

1.  Identify the logical design structure, namely the components of a system and their inter-relationships
2. Realize this structure in a form which can be executed. This latter stage is sometimes considered as detailed design and sometimes as programming.

 Design decomposition:

• Function oriented decomposition
• Data oriented decomposition
• Object Oriented decompostion

Design approaches:

 There are two types of Design approaches in the Software Design process. They are

a) Top-down design

b) Bottom-up design

a) Top-down design:

This design activity must begin with the analysis of the requirements definition and implementation details at first,should not be considered.

A project is decomposed into sub projects,and this procedure is repeated until the sub tasks have become so simple that an algorithm can be formulated as a solution.

Abstraction proves to be the best medium to render complex system comprehensible, the designer is involved only with those aspects of the system that are necessary for understanding before the next step or during the search for a solution.

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b) Bottom-Up design:

The fundamental idea of this design is to perceive the hardware and layer above it as an abstract machine.

The Bottom-Up design begins with the given of concrete machine and successively develops one  abstract machine after the other by adding needed attributes,until a machine has been achieved that provides the functionality that the user requires.

process design specifications

1. Name and description
2. inputs and outputs
3. main algorithm
4. Pseudo code
5. Timing behavior
6. Error states

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Read also : Waterfall model and software process