Requirement Classification Nisa’ul Hafidhoh Teknik Informatika

User vs. System Requirement User Requirement Statements in natural language about WHAT the system provides and its operational constraints & assumptions; with some diagrams if necessary audience: Written for customers System Requirement Detailed descriptions of the system’s functions, constraints & assumptions. Defines what should developed in the system

System and software requirement Descriptions and specifications of a system It covers – a high-level statement – assumptions and constraints – detailed functional specification – quality criteria about the system and software Another functions – The basis for a bid for a contract - therefore must be open to interpretation; – The basis for the contract itself - therefore must be defined in detail;

Reqirement Classification

Functional and non-functional requirements Functional requirements – Statements of functionalities that the system should provide Reaction upon particular inputs Behaviour in particular situations – E.g., The system will authenticate the user prior its access Non-functional requirements – Qualities criteria that should be fulfilled by the system when it performs its functionalities – E.g., The authentication process will be done with in 5 seconds Domain requirements (Domain Properties/assumptions) – Statements that reflect characteristics of the domain. – E.g., The authentication server will always be available (i.e., 24/7)

Functional requirements Describe functionality or system services. – Depend on the type of software, expected users and the type of system where the software is used. – Functional user requirements may be high- level statements of what the system should do but functional system requirements should describe the system services in detail.

Non-functional requirements (NFRs) These define system properties and constraints e.g. reliability, response time and storage requirements. Constraints are I/O device capability, system representations, etc. Process requirements may also be specified mandating a particular CASE system, programming language or development method. Non-functional requirements may be more critical than functional requirements. If these are not met, the system is useless.

Non-functional classifications Product requirements – Requirements which specify that the delivered product must behave in a particular way e.g. execution speed, reliability, etc. Organizational requirements – Requirements which are a consequence of organizational policies and procedures e.g. process standards used, implementation requirements, etc. External requirements – Requirements which arise from factors which are external to the system and its development process e.g. interoperability requirements, legislative requirements, etc.

Non-functional requirement types

Case Study Regional Library of Central Java Developers asked to set up a library information system. The system is built to be able to perform data management and members of the book. To run this system needs a PC with a minimum specification Pentium 2 and 10 GB hard drive. And database systems must be equipped with a password to maintain the security of the system. To borrow, members must register in advance through the system. The system response when the registration process should not be more than 2 seconds. The system can display the number of books borrowed and their return date. The system can also perform transactions both total return of books borrowed books and fines paid (if any).

Goal Level Req. Related to business goals E.g.: In a company profile, there is a requirement to promote their product, such as send promotion mail automatically to the members (Subscribe system)

Domain level requirements Related to problem area Every domain has different requirement

Product level requirements Related to the product E.g.: Software must compatible for every platform such as windows, linux, unix, etc.

Design level requirements what to build E.g.: Design interface must be understood by novice user.

Primary requirements elicited from stakeholders Requirements is elicited directly from client/stakeholder.

Derived requirements derived from primary requirements Elicited from previous primary requirement, usually derived / additional detailed from primary req.

Product req. VS Process req. Product requirements: Business need Process requirements: How people will interact with the system

Role based requirements E.g.: Customer requirements, IT requirements, system requirements, and security requirements