Linux System Study Notes: Preface, linux Study Notes

Linux System Study Notes: Preface, linux Study Notes
Linux System Study Notes: Preface

Zookeeper Linux is a free-of-charge and freely-spread Unix-like operating system. It is a POSIX and UNIX-based operating system that supports multiple users, multi-tasking, multithreading, and multi-CPU. It can run major UNIX tool software, applications and network protocols. It supports 32-bit and 64-bit hardware. Linux inherits the network-centric Unix design philosophy and is a stable multi-user network operating system.

I use Ubuntu as my Linux instance and use APUE (version 3rd) as my learning blueprint.

1. Unix/Linux architecture

:

The kernel interface is called a system call. The public function library is built on the system call interface. Applications can use both the public function library and the system call function. Shell is a special application that provides an interface for running other applications.

2. The main module of Linux kernel 2.1 process scheduling SCHED

Process Scheduling refers to the system's policy for switching between various States of processes. There are three policies for Process Scheduling in Linux:
* SCHED_OTHER time-based scheduling policy
* SCHED_FIFO real-time scheduling policy, first served
* SCHED_RR real-time scheduling policy, time slice Rotation

2.2 memory management MMU

Memory Management is a memory sharing policy between multiple processes. In Linux, the main concept of memory management is virtual memory.

2.3 Virtual File System VFS

Linux supports multiple file systems. The most common file formats are ext2 and ext3 (ext4 is the ultimate version of ext3). ext2 file systems are used for fixed file systems and movable file systems, ext3 adds the log function to the foundation of ext2. The two can be converted to each other.

2.4 Network Interface

Linux supports multiple network interfaces and protocols. Network interfaces are divided into network protocols and drivers. network protocols are a communication standard for network transmission, while network drivers are drivers for hardware devices.

2.5 inter-process communication

The Linux operating system supports multiple processes. data exchange between processes is required to complete control, collaboration, and other functions, in Linux, inter-process communication methods include pipeline, signal, message queue, shared memory, and socket.

3. Linux directory tree structure