functional and non functional requarnment

Functional and Non- Functional Requirements Of the System:

Functional requirements:it's mean how the system will work what will be the functionalities of the system for the customer requirements,manager other external entities related to the system;
Non-Functional requirements:it's concerned with constraint of the system,what will be the constraint of the system under which it give access to the authorized user.what will be the system response time,storage requirements,the non-functional requirements are more critical than the function because if these requirements are not meet >the system will be useless