Why need analysis? What are the general requirements for software systems?

Reason:

It takes a lot of manpower, material resources and financial resources to make a software. If the software is not used or used by people or the software does not meet the needs of customers, it is necessary to re-do, then all the previous investment will be done without employment. So we need to do the demand analysis ahead of time.

Demand:

1. Functional Requirements. The software system must complete the specified function.

2. Performance requirements. The software system must have short response time, fast information rate, large memory capacity, large disk capacity and high security.

3. Reliability and availability requirements.

4. Error handling requirements. The system selectively presents such error handling requirements when an error is found.

Why need analysis? What are the general requirements for software systems?