如何设计架构（How to design architecture）.doc

如何设计架构(How to design architecture)
Part 1 layer
The concept of layer (layer) is a very difficult concept in puter field. puter itself embodies a layer of concepts: system call layer, device driver layer, operating system layer, and CPU instruction set. Each layer is responsible for its responsibilities. Network is also the concept of layer, the most famous seven layer protocol of TCP/IP.
Layers are equally good for software applications. Why? Let's see what benefits are in using the layer technology:
You use layers, but you don't need to understand the layers of implementation details.
You can use another technique to change the underlying layer without affecting the application of the layer above.
It can reduce the dependence between different layers.
It is easy to make out the layer standard.
The bottom layer can be used to build multiple services on top of the layer.
Of course, layers have weaknesses:
It is impossible to encapsulate all the functions. Once the function changes, it will spread to all layers.
Efficiency reduction.
Of course, one of the most difficult questions is what the layers are, and what responsibility they have to take.
A typical three story structure
The three layer structure is very familiar to everyone. It represents the (presentation) layer, the domain (domain) layer, and the infrastructure (Infrastructure) layer.
The presentation layer logic deals with the interaction between users and software. Now the most popular is the windows graphical interface (wimp) and the HTML based interface. The main responsibility of the presentation layer is to provide users with information and to translate user instructions. Transfer to business layer and infrastructure layer.
The underlying layer logic munication between processing and other systems, representing the system performing tasks. For example, database system interaction, interaction with other application systems, etc.. Most of the information systems, the biggest logic of thi