One of modern structured analysis's online Reading Notes

Mordern structured
Analysis is a classic book of Structured Software Engineering. To study the characteristics of Japanese software engineering, I decided to read books about structured software engineering. This book must be my first choice.

Chapter 1 focuses on system analysis, which is very interesting and more difficult than programming.

Chapter 2 describes what a system is. At the end of this chapter, I will introduce general system principles. These general principles will lay the foundation for later system analysis:

1. As a specialized system, at least it must be able to adapt to different environments.

This poses a challenge to system design. To adapt to different environments, we need to make more generalization. This also points out the direction. As a system, more research on its general structure and behavior, rather than special structure and behavior. If it is too special, then the vitality of this system is effective and will soon die out. As pointed out in the fourth point, as the system continues to grow and change, systems that cannot adapt to different environments will soon die.

2. Large systems will need more resources to maintain daily operation.

This points out that, as a large system, building and maintaining it requires more resources, it also requires more systematic construction and maintenance for a large system. The larger the system, the more formal the rules are required. Otherwise, the system will crash easily.

This refers to the system's dependence on resources. If the resources disappear, the system will die.

3. A system is always part of another system. It can be divided into multiple subsystems.

A very important idea in system design is decomposition and combination. If we cannot break down and combine without loss, we should at least find a way to simulate it as much as possible.

This indicates the external structure of the system.

4. The system is constantly growing and changing.

Since growth changes, there will be a process of birth, growth, maturity, decline, and extinction, which cannot be blocked. Because a system is always part of another system, Phoenix Nirvana can also be expected.

We can imagine that the rebirth of a company like IBM is an example of Phoenix Nirvana.

Since it is growing and changing, it also shows its dynamic characteristics

5. The interaction between components of the system is often complex and unknown.

This shows the internal structure of the system. Because of the complexity and ignorance, we need some methods to study, how they are formed, and the patterns between them.

 

Based on the above five basic principles, we can think that if we need to build a system, we need:

1. Identify the running environment and anticipate changes in the environment, so that the system can adapt to changes in the environment.

2. Proper resources are required to build and maintain the system operation.

3. We need to analyze how a system interacts with an external system.

4. We need to analyze the relationship between components in a system and their components.

5. We need to analyze the structure and behavior of a system, build it, publish it, and maintain its operation.

 

these ideas run through the rest of this book.