Operating Systems: Concurrent and Distributed Software Design

25.2. Kernel structure

This section describes how the structure of the UNIX kernel has developed from the format introduced in Section 24.3. Although the core functions remain the same, the mechanisms by which they are composed to form the running kernel have become more flexible and the interfaces between different components have become more consistently defined.

25.2.1. Loadable kernel modules

The system structure shown in Figure 24.2 places a large number of components within the kernel; for instance there must be a device driver for each device that the system is using and there must be implementations of the file systems, network protocols and IPC APIs that might be used. This structure means that, if the system is to operate without interruption, ...