Layered Kernel

operating-systems

Definition

Layered Kernel

A layered kernel is an operating system architecture that organises its functions into a hierarchy of levels. Each layer is constructed on top of the layer below it, providing an abstract interface to the higher layers.

In this model, Layer $n$ can only use the services provided by Layer $n-1$ and provides its own services to Layer $n+1$. Most layers in this architecture execute in kernel mode.

Characteristics

• Modularity and Debugging: Easier to debug because each layer can be tested independently. If an error is found in Layer $n$, it is likely contained within that layer or the layers below it.
• Abstraction: Hides the details of the hardware from the higher-level applications.
• Performance Overhead: Crossing multiple layers for a single request (e.g., an application requesting a file read) can be slower than direct calls in a monolithic design.