Software engineering is known as layered technology because it is built on top of a series of layers, each one providing a specific set of capabilities and abstractions. These layers are designed to simplify the process of building and maintaining software, by providing a clear separation of concerns and a consistent set of interfaces and protocols.

The bottom layer of software engineering is the hardware layer. This layer is composed of the physical components of a computer system, such as the CPU, memory, and storage. The hardware layer provides the basic building blocks for all software systems, and is responsible for performing low-level operations like memory access and input/output.

The next layer is the operating system layer. The operating system is responsible for managing the hardware resources of a computer system and providing a consistent interface for software to interact with the hardware. The operating system provides services such as memory management, file system access, and process management.

The third layer is the middleware layer. Middleware is a software layer that sits between the operating system and the application layers. It provides additional services and abstractions that are not provided by the operating system. Examples of middleware include databases, message queues, and web servers.

The fourth layer is the application layer. This is the topmost layer of software engineering and is where the majority of software development takes place. The application layer is responsible for providing the functionality that users interact with. Applications are built on top of the lower layers, making use of the services and abstractions provided by the operating system, middleware, and hardware.

The layered approach of software engineering provides several benefits. First, it allows for a clear separation of concerns. Each layer is responsible for a specific set of tasks, and is isolated from the other layers. This makes it easier to understand and maintain software, as developers can focus on the specific concerns of each layer without needing to understand the details of the other layers.

Second, the layered approach provides a consistent set of interfaces and protocols. Each layer provides a set of well-defined interfaces and protocols that the other layers can use to communicate with it. This allows for easy integration of different components and systems, and makes it easier to replace one component with another.

Third, the layered approach allows for reuse of code and components. By building on top of existing layers, developers can reuse existing functionality and abstractions, which can save time and effort when building new software.

Fourth, the layered approach helps in security, as the security measures can be implemented on each layer, and any vulnerabilities on one layer doesn’t affect the other layers.

Finally, the layered approach allows for incremental development. By building software in layers, developers can work on one layer at a time, and add new layers as necessary. This makes it easier to iterate and improve software over time, and allows for a more flexible and adaptable development process.

In conclusion, software engineering is known as layered technology because it is built on top of a series of layers, each one providing a specific set of capabilities and abstractions. This layered approach provides a clear separation of concerns, consistent interfaces, code reuse, better security and incremental development, making it easier to understand, maintain and improve software.