The document discusses software requirements analysis and outlines the key aspects of developing requirements for software systems. It notes that a Software Requirements Specification (SRS) describes what a software system should do without describing how it will do it. An SRS establishes agreement between clients and suppliers and provides a reference for validation. Characteristics of an effective SRS include being correct, complete, unambiguous, verifiable, consistent, modifiable and traceable. Components of an SRS include functionality, performance, design constraints and external interfaces. Data flow diagrams are used to model systems and show the flow of data through transformations.

1. Software Requirements analysis
Software requirements:-A condition of capability
needed by a user to solve a problem or achieve an
objective.
SRS :- That describes what the proposed software
should do without describing how the software will
do it.

2. Need for SRS
Three major parties interested in a new system:
The client
The developer
The end users.
An SRS establishes the basis for agreement between the
client and the supplier on what the software product will
do.
An SRS provides a reference for validation of the final
product.

3. Characteristics of an SRS
1. Correct
2. Complete
3. Unambiguous
4. Verifiable
5. Consistent
6. Ranked for import and/or stability
7. Modifiable
8. Traceable

4. Components of an SRS
1. Functionality
2. Performance
3. Design constraints imposed on an implementation
4. External interfaces

5. Structured Analysis
Data flow based modeling, often referred to as the
structured analysis technique, uses function-based
decomposition while modeling the problem.
> A DFD shows the flow of data through a system.
It views a system as a function that transforms the inputs
into desired outputs.
Any complex system will not perform this transformation
in a single step, and a data will typically undergo a series of
transformations before it becomes the output.
The DFD aims to capture the transformations that take
place within a system to the input data so that eventually
the output data is produced.

6. Decomposition Diagrams

7. DFD : Choice of Symbol
• Sarson Yourdan
1.0 1.0
Process Process
Description Description
entity name
entity name
Data Store
Data Store
name name
Data Flow Name Data Flow Name

8. Example