Design of SoftwareOrganized By: Vinay Arora              Assistant Professor             CSED, Thapar University          ...
Disclaimer            This is NOT A COPYRIGHT                   MATERIAL            Content has been taken mainly from the...
Top Down Design  In principle, top-down design involves starting at the uppermost components in  the hierarchy and working...
Top Down Structure                Vinay Arora                   CSED
Top Down Structure                System level                               Sub-system                               leve...
Update File as Main Procedure & Various Sub                Procedures                     Vinay Arora                     ...
Coupling   A measure of the strength of the inter-connections between system   components.   Loose coupling means componen...
Coupling           Vinay Arora              CSED
Tight Coupling       Module A                   Module B       Module C                   Module D                  Shared...
Loose Coupling                  Module A                  A’s data      Module B                     Module C       B’s da...
Cohesion   A measure of how well a component “fits together”.   A component should implement a single logical entity or fu...
Coupling & Cohesion               Vinay Arora                  CSED
Span of Control   Span of control is the term now used more commonly in business   management, particularly human resource...
Shared Module                Vinay Arora                   CSED
Reference List1. System Analysis and Design Methods By Jeffrey L Whitten & Lonnie D Bentley2. Analysis & Design of Informa...
Thnx…  Vinay Arora     CSED
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A&D - Design of Software

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A&D - Design of Software

  1. 1. Design of SoftwareOrganized By: Vinay Arora Assistant Professor CSED, Thapar University www.slideshare.net/aroravinay
  2. 2. Disclaimer This is NOT A COPYRIGHT MATERIAL Content has been taken mainly from the following books:System Analysis and Design Methods By Jeffrey L Whitten & Lonnie D Bentley , Analysis & Design of Information Systems By James A. Senn, System Analysis & Design By Elias M. Awad,Modern System Analysis & Design By Jeffrey A. Hoffer, Joey F.George & Joseph S. Valacich Vinay Arora CSED
  3. 3. Top Down Design In principle, top-down design involves starting at the uppermost components in the hierarchy and working down the hierarchy level by level. In practice, large systems design is never truly top-down. Some branches are designed before others. Designers reuse experience (and sometimes components) during the design process. Each function the system will perform is first identified and then developed in greater detail. This is termed as Stepwise Refinement. Vinay Arora CSED
  4. 4. Top Down Structure Vinay Arora CSED
  5. 5. Top Down Structure System level Sub-system level Vinay Arora CSED
  6. 6. Update File as Main Procedure & Various Sub Procedures Vinay Arora CSED
  7. 7. Coupling A measure of the strength of the inter-connections between system components. Loose coupling means component changes are unlikely to affect other components. Shared variables or control information exchange lead to tight coupling. Loose coupling can be achieved by component communication via parameters or message passing. Vinay Arora CSED
  8. 8. Coupling Vinay Arora CSED
  9. 9. Tight Coupling Module A Module B Module C Module D Shared data area Vinay Arora CSED
  10. 10. Loose Coupling Module A A’s data Module B Module C B’s data C’s data Module D D’s data Vinay Arora CSED
  11. 11. Cohesion A measure of how well a component “fits together”. A component should implement a single logical entity or function. Cohesion is a desirable design component attribute as when a change has to be made, it is localized in a single cohesive component. Various levels of cohesion have been identified. Vinay Arora CSED
  12. 12. Coupling & Cohesion Vinay Arora CSED
  13. 13. Span of Control Span of control is the term now used more commonly in business management, particularly human resource management. Span of control refers to the number of subordinates a supervisor has. In software design span of control is the total count of sub modules as controlled by a main module. Vinay Arora CSED
  14. 14. Shared Module Vinay Arora CSED
  15. 15. Reference List1. System Analysis and Design Methods By Jeffrey L Whitten & Lonnie D Bentley2. Analysis & Design of Information Systems By James A. Senn3. System Analysis & Design By Elias M. Awad4. Modern System Analysis & Design By Jeffrey A. Hoffer, Joey F.George & Joseph S. Valacich etc……. Vinay Arora CSED
  16. 16. Thnx… Vinay Arora CSED

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