The Linux kernel can be thought as logically composed of many Subsystems. They may be not implemented as separate directories in the tree structure due to the tight coupling among them all. 1. Processes 1. [:KernelHacking-HOWTO/Subsystems/Exceptions and Interrupts Handling:Exceptions and Interrupts Handling] 1. Time, Clocks and Timers 1. Synchronization 1. Inter Process Communication 1. Memory Management, Virtual Memory Management 1. Virtual File system 1. Process Scheduling 1. System Calls 1. Modules 1. Add More