The Art of Linux Kernel Design

From Power-Up to the Main Function


Loading BIOS, Constructing Interrupt Vector Table, and Activating


Interrupt Service Routines in the Real Mode


Loading the OS Kernel and Preparing for the Protected Mode


Transfer to 32-bit Mode and Prepare for the Main Function


Summary


Device Initialization and Process 0 Activation


Set Root Device 2 and Hard Disk


Set Up Physical Memory Layout, Buffer Memory, Ramdisk, and Main Memory


Ramdisk Setup and Initialization


Initialization of the Memory Management Structure mem_map


Hooking the Interrupt Service Program


Initialize the Request Structure of the Block Device


Binding with the Interrupt Service Routine of Peripherals and Establishing the Human-Computer Interaction Interface


Time Setting


Initialize Process 0


Initialize the Buffer Management Structure


Initialize the Hard Disk


Initialize the Floppy Disk


Enable the Interrupt


Process 0 Moves from Privilege Level 0 to 3 and Becomes a Real Process


Creation and Execution of Process 1


Creation of Process 1


Kernel Schedules a Process for the First Time


Turn to Process 1 to Execute


Creation and Execution of Process 2


Open the Terminal Device File and Copy the File Handle


Fork Process 2 and Switch to Process 2 to Execute


The System Gets to the Idle State


File Operation


Install the File System


Opening a File


Reading a File


Creating a New File


Writing a File


Modifying a File


Closing a File


Deleting a File


The User Process and Memory Management


Linear Address Protection


Paging


When to Apply the Process to a New Page and When You Should Not


Map the New Application Page to the Linear Address in the Process


Complete Process of User Process from Creation to Exit


Multiple User Processes Run Concurrently


Buffer and Multiprocess Operating File


Function of Buffer


Structure of Buffer


The Function of b_dev, b_blocknr, and Request


Function of Uptodate and Dirt


Function of the Count, Lock, Wait, Request


Example 1: Process Waiting Queue of Buffer Block


Overall Look at the Buffer Block and the Request Item


Example 2: Comprehensive Examples of Multiprocess Operating File


Inter-Process Communication


Pipe Mechanism


Signal Mechanism


Summary


Operating System's Design Guidelines


Run a Simple Program to See What the Operating System Has Done


Thoughts on the Design of the Operating System: Master-Slave


Mechanism


Three Key Techniques in Realizing the Master


Decisive Factor in Establishing the Master-Slave Mechanism: The Initiative


Relationship Between Software and Hardware: Host and Process, Peripherals and File


Parent and Child Processes Sharing Page


Operating System's Global Interrupt and the Process's Local Interrupt: Signal


Summary


Conclusion