Why do you need to conduct a demand analysis? What are the general requirements for software systems?

"Demand Analysis" determines what the system must accomplish, which is to put forward complete, accurate and specific requirements for the target system. In order to develop software products that really meet the needs of users, we must first know the needs of users, only in-depth understanding of the needs of users, our work will be meaningful.

There are usually the following requirements for software:

Functional Requirements:

Specify the services that the system must provide;

Performance requirements:

Specify the timing constraints or capacity constraints that the system must meet, usually including the requirements for speed, information rate, main memory capacity, disk capacity, security, and so on;

Reliability and Availability requirements:

Specifies the reliability of the system, the availability of which quantifies the extent to which users can use the system;

Error Handling requirements:

Explain how the system should respond to environmental errors;

Interface Requirements:

A format that describes the communication of an application system to its environment;

Reverse demand:

Explain what the software system should not do;

Possible future requirements:

Should clearly list those that are not part of the current system development category,

But according to the analysis will be

Requests that may be made

Why do you need to conduct a demand analysis? What are the general requirements for software systems?