Scope of Systems Requirements: Definition o f Requirements Not to define the full system Not to define the full system Describe or define the essential properties or attributes Describe or define the essential properties or attributes Definition Definition An abstract description of services, which the system is expected to provide, and constraints under which the system must operate.

TYPES OF REQUIREMENTS User Requirements User Requirements System Requirements System Requirements Functional Requirements Functional Requirements Non – Functional Requirements Non – Functional Requirements

User requirements User requirements are the statements, User requirements are the statements, in a natural language and diagrams, in a natural language and diagrams, what services the system is expecting to providing and constraints under it which what services the system is expecting to providing and constraints under it which it should operate it should operate

System Requirements System services and constraints in detail System services and constraints in detail

Functional Requirements How the system should react to the particular inputs How the system should react to the particular inputs How the system should behave to the particular situations How the system should behave to the particular situations What the system should not do What the system should not do

Non - Functional Requirements Constraints on the services or functions Constraints on the services or functions Time constraints Time constraints Constraints on the development process Constraints on the development process

Fact – Finding Techniques By Investigating The Current System  Interviews – Used to collect information verbally, from managers/employees.  Unstructured – a free question answer session  Structured questioning- use standard questioning  Open-response- Interviewees are allowed to answer in their own words.  Closed-response- selects from a given set of answers

Fact – Finding Techniques By Investigating The Current System  Open- feeling, opinions, experiences; good for exploring a process/problem Questionnaire- a useful alternative to interviews. May be the only feasible way to contact a large group Questionnaire- a useful alternative to interviews. May be the only feasible way to contact a large group Record Review- Examine the written Record Review- Examine the written

Fact – Finding Techniques By Investigating The Current System  Observation- provides information that could not be obtained in any other way. Most useful processes are carried out and whether specified steps actually occur. Observation can change what people do

System Model --- Context Model  which lack information about detailed system functionality. A more detailed system model should  Details of the system inputs  Details of the system outputs  Details of the system data processing  Details of control in the system

Analyzing the Current System Determine Info. Requirements Determine Info. Requirements  Information Architecture  Objective  Data modeling

Analyzing the Current System Document & Analyze Existing Information System Document & Analyze Existing Information System  Data Flow Diagram  Other Graphic Techniques  System flowchart  Rich pictures  Simulation

Analyzing the Current System Isolate Deficiencies in the System Isolate Deficiencies in the System  Information  Technology  Process  Personnel

Identifying requirements Data from analysis of current system Data from analysis of current system Prototyping Prototyping Joint Application Design Joint Application Design Research Research

Without Prototype Feasibility study Feasibility study Requirement Analysis and capture Requirement Analysis and capture Requirement definition (end – user) Requirement definition (end – user) Requirements Specification Requirements Specification requirements is set out and acts as a basic foundation between user and software developer requirements is set out and acts as a basic foundation between user and software developer

Output: Project Proposal Project definition/description Project definition/description Justification Justification Cost (resource requirements) Cost (resource requirements) Time schedule Time schedule Objectives Objectives Constraints Constraints