In the software life cycle, what is the stage that solves 'what does the software do'?

In the software life cycle, the stage that solves "what the software does" is: requirements analysis. Requirements analysis is to have an in-depth and specific understanding of the user's needs, and to be completely consistent with the user's ideas on what the developed system should do; to clarify what the target system must do, and to determine what functions the target system must have.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

In the software life cycle, the stage that can accurately determine "what the software system must do" is: requirements analysis.

Tasks at each stage of the software life cycle:

1. Problem definition

Determine what the problem to be solved is (what) , through the customer interview survey, the system analyst briefly writes a written report on the nature of the problem, project goals and project scale. After discussion and necessary modifications, this report should be confirmed by the customer.

2. Feasibility study

Determine whether there is a solution to the problem. The results of the feasibility study are an important basis for the customer to decide whether to continue the project. Generally speaking, only those projects where the investment is likely to achieve greater benefits are worth continuing.

3. Requirements analysis

Understand the user's needs in depth and in detail, and be completely consistent with the user's ideas on what the system to be developed should do. Clarify what the target system must do and determine what functions the target system must have. The logical model of the system is usually represented by data flow diagrams, data dictionaries and brief algorithms. Use "Specifications" to document the requirements for the target system.

4. Outline design (overall design)

In summary, how should the target system be implemented, several possible solutions to achieve the target system should be designed, and the system structure of the program should be designed, that is, determine Which modules the program consists of and the relationships between modules.

5. Detailed design

Implement the specific work of the system and write detailed specifications. Programmers can write actual program codes based on them. Detailed design is also called module design. At this stage, each module will be designed in detail and the algorithms and data structures required to implement the module's functions will be determined.

6. Coding and unit testing (coding accounts for 10%-20% of the total development workload)

7. Comprehensive testing (testing accounts for 40%-50% of the total development workload)

8. Software maintenance

Through various necessary maintenance activities, the system can continuously meet the needs of users. Mainly divided into corrective maintenance, adaptive maintenance, perfective maintenance and preventive maintenance.

Extended information

Software life cycle baseline

1. Functional baseline(functional baseline)

The functional baseline refers to the At the end of the analysis and software definition phase, the specifications of the system to be developed are specified in the system design specification that has been formally reviewed and approved; or it refers to the treatment stipulated in the agreement or contract signed by both the project entrusting unit and the project undertaking unit. Specifications of the software system to be developed;

or specifications of the software system to be developed that are applied by subordinates and approved by superiors or directly issued by superiors in the project mission statement. A functional baseline is the initial approved functional configuration identification.

2. Assigned baseline (allocated baseline)

The assigned baseline refers to the specification of the software requirements that has been formally reviewed and approved at the end of the software requirements analysis phase. The assignment baseline is the originally approved assignment configuration ID.

3. Product baseline(product baseline)

The product baseline refers to all configuration items of the developed software products that have been formally reviewed and approved at the end of the software assembly and system testing phases. specifications. The product baseline is the initial approved product configuration designation.

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