What Is a Modular System?

Overview

Overview

The modular operating system is composed of an installation kernel and an installation password package, and belongs to an open source operating system.

Modular programming technology is a structured programming technology that appeared in the 1960s. This technology is based on the "decomposition" and "modularization" principles to control the complexity of large software. In order to make the operating system have a clearer structure, the operating system is no longer directly composed of numerous processes, but the operating system is carefully divided into several modules with certain independence and size according to their functions.

Chinese name

Modular operating system

Constitute

Install the kernel and install the password package

Belong to

Open source operating system

Advantages

Minimize system footprint

Introduction to Modular Operating System

Each module of the modular operating system has certain aspects of management functions, such as process management module, memory management module, I / O device management module, etc., and carefully specifies the interfaces between the modules so that each module can pass The interface implements interaction. Then, the modules are further subdivided into interfaces between several sub-modules with certain functions. If the sub-module is larger, it can be further subdivided. We call this design method a module-interface method, and the operating system formed by it is an operating system with a modular structure. As shown in the figure,

It is a modular OS structure composed of modules and sub-modules.

Independence of modular operating system modules

In the module-interface design method, the key issues are the division of the modules and specifying the interfaces between the modules. If we divide the module too small when dividing the module, although it can reduce the complexity of the module itself, it will cause too many connections between the modules and cause the system to be chaotic; if the module is too large, the It will increase the complexity inside the module and increase the internal connections. Therefore, there should be a trade-off between the two when dividing modules.

In addition, when dividing the modules, full attention must be paid to the independence of the modules. Because the higher the independence of the modules, the less the interaction between the modules and the clearer the structure of the system. There are two criteria for measuring module independence:

1. Cohesion refers to the closeness of the connections between the various parts of the module. The higher the cohesion, the stronger the independence of the module.

2. Coupling degree refers to the degree of mutual connection and interaction between modules. Obviously, the lower the degree of coupling, the better the independence of the module.

Modular operating system advantages

The operating system developed by the module-interface method has the following obvious advantages over the unstructured operating system:

1. Improve the correctness, understandability and maintainability of the operating system design;

2. Enhance the adaptability of the operating system;

3. Speed up the development process of the operating system.

The modular structure design can minimize the space occupied by the system. Users can compile application software according to their actual needs, which will greatly increase the hard disk usage and reduce the waste of CPU and memory resources. At the same time, the size of the installation package is greatly reduced.

Disadvantages of modular operating systems

The modular structure design has the following problems:

1. During the design of the OS, it is difficult to specify the interfaces between the modules to meet the actual requirements for the interfaces after the modules are completed.

2. During the OS design phase, the designer must make a series of decisions, and each decision must be based on the previous decision. However, in the design of the modular structure, the design of each module goes hand in hand, and a reliable order of decisions cannot be found, resulting in "disorderliness" of various decisions, which will make it difficult for program designers to achieve "each step in the design Decisions are made on a reliable basis ", so the module-interface method is also called the" disordered module method ".