Evolution may not only happened in IT section. Evolution happen in every other fields even human has a evolution. So in this article I will explain about the evolution of software architecture and I will take you from standalone systems to microservices.

One Tier Architecture

**One Tier application is also known as a Standalone application which is the simplest architecture. **It is equivalent to running the application on a personal computer. So all the required components for an application to run are on a single application or server. So Presentation layer, Business logic (application)layer, and data layer are all located on a single machine or a software package. Some of the examples for one tier architecture is MP3 player and MS office. So in one-tier architecture data can be stored in the local system or a shared drive. Speaking about some of the advantages of this type of systems are,

1. It’s simple and easy to implement.
2. Very efficient.
3. No compatibility and no context switching issues

When we think about some of the disadvantages,

1. Since it only in one machine it does not support remote/ distributed access for data resources.

Two-Tier Architecture

After one-tier architecture, we moved to two-tier architecture. The two-tier** architecture is also known as client-server application**. So this architecture is divided into two parts. Those are,

1. Client Application (Client Tier)

2. Database (Data Tier)

The client system handles both Presentation and Business layer(Application layer) and the Server system handles the Database layer. So basically what happens is the client system sends the request to the server system and the Server system processes the request and sends back the data to the client system. So the communication takes place between the client and the server. When we consider the advantages,

1. Easy to maintain and the modification is a bit easy.
2. Faster communication.

Some of the disadvantages are,

1. Application performance will be decreased when increasing the number of users.

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