Can non functional requirements generate a new functional requirement

What a great question!

In software development, non-functional requirements (NFRs) are often considered orthogonal to functional requirements (FRs). NFRs describe the system's behavior, performance, and quality attributes, such as security, usability, scalability, and reliability, whereas FRs describe what the system should do.

However, it's not uncommon for NFRs to indirectly influence or even generate new FRs. Here are some scenarios where NFRs can lead to new FRs:

  1. Security: A security NFR might require the system to encrypt sensitive data. This could lead to a new FR, such as "The system must encrypt all user data at rest and in transit."
  2. Usability: A usability NFR might require the system to provide clear error messages. This could lead to a new FR, such as "The system must display clear and concise error messages to users."
  3. Scalability: A scalability NFR might require the system to handle a large number of concurrent users. This could lead to a new FR, such as "The system must be able to handle at least 10,000 concurrent users without a significant decrease in performance."
  4. Reliability: A reliability NFR might require the system to have a high uptime. This could lead to a new FR, such as "The system must be available 99.99% of the time, with no more than 1 hour of downtime per month."
  5. Performance: A performance NFR might require the system to respond quickly to user input. This could lead to a new FR, such as "The system must respond to user input within 2 seconds, 95% of the time."

In these scenarios, the NFRs are not directly generating new FRs, but rather, they are influencing the design and functionality of the system in a way that leads to new FRs. The NFRs are providing constraints or guidelines that shape the development of the system, which in turn, lead to new FRs.

So, to answer your question, while NFRs are not directly generating new FRs, they can certainly influence the development of the system in a way that leads to new FRs.