- The Linux operating system is composed of four major subsystems:
- User Applications — examples include a word-processing application and a web-browser.
- O/S Services — considered part of the operating system; also, the programming interface to the kernel is included.
- Linux Kernel — abstracts and mediates access to the hardware resources.
- Hardware Controllers — for example, the CPU, memory hardware, hard disks, etc.
- Each subsystem layer can only communicate with the subsystem layers that are immediately adjacent to it.
- The dependencies between subsystems are from the top down.
- presents a virtual machine interface to user processes.
- composed of five main subsystems
- Process Scheduler
- Memory Manager
- Virtual File System
- Network Interface
- Inter-Process Communication
System Data Structures
- Task List
- Memory Map
- Data Connection