One 、 Fundamentals of computer

The hierarchy of storage

L0 register
L1 L1 Cache SRAM
L2 L2 Cache SRAM
L3 L3 Cache SRAM
L4 Main memory DRAM
L5 Local secondary storage Local disk
L6 Remote secondary storage web The server
000. Linux Base zero ( Fundamentals of computer 、 Operating system foundation )

Important concepts
  • Concurrent : hold CPU Time for fragmentation , Let each program in the CPU Upper rotation , Make one The illusion that multiple programs are running at the same time
  • Multithreading : Multiple processes are required , Save the site where the program is executed
  • cache : Save non persistent data , Support a large number of concurrent access
  • asynchronous : encounter I/O operation , The program registers a hook function There? , The thread then processes other requests , wait until I/O Operation completed , The system will send an event to this thread , Thread is Go back to the previous hook function ( It's also called a callback function ) To deal with it .
  • Single thread : There is also a huge advantage to single threading , There is no competition , No need to lock

Two 、 Operating system foundation

Linux Kernel version composition :

The major version number Sub version number Last version number Package version number Manufacturer version
000. Linux Base zero ( Fundamentals of computer 、 Operating system foundation )

Linux Three mainstream distributions :

Debian、RedHat、SUSE
slackware:SUSE Linux Enterprise Server (SLES)

RedHat Linux The series was developed by red cap company linux Distribution version , Include Fedora、RHEL、CentOS and Oracle Linux Multiple versions

debian: ubuntu,deepin( depth ),mint
Debian Include Ubuntu Upstream of multiple releases within

  • Debian It's a pure open source project with a focus on stability
  • Debian Three version branches :Stable,testing and unstable
  • Ubuntu Is based on Debian Of unstable Version enhancement comes from
Linux Philosophical thought
  • Everything is a document
  • small , A single purpose program
  • Link program , Work together on complex tasks
  • Avoid confusing user interfaces
  • Configuration data is stored in text