Programmer Group

  this article describes the ARM32 processor. Kernel page table: that is, the main kernel page table mentioned in the book. In the kernel, it is actually a section of memory stored in the global directory init of the main kernel page_ Mm. PGD (swap_pg_dir), the hardware is not used directly. Process page table: each process's own page ...

Construction of centos7 Nacos service registry Since the spring cloud registry Eureka has long stopped maintenance, we use Nacos official: https://nacos.io/zh-cn/docs/what-is-nacos.html Welcome to the world of Nacos! Nacos is dedicated to helping you discover, configure, and manage microservices. Nacos provides a set of easy-to-use feature ...

Linux operating system boot process Overview of the boot process 1. Post After the server host is powered on, the CPU, memory, graphics card, keyboard and other devices will be preliminarily tested according to the settings in the BIOS of the motherboard. After the test is successful, the system control will be handed over according to t ...

IO multiplexing: listen to multiple file descriptors at the same time 1.select Interview frequencyWhat are the disadvantages of select and poll = > using epollepoll ET mode and LT mode The focus is on the read event EPOLLIN, because the read event requires data in the buffer before it can be read, and if there is no data, it will b ...

Command format command [options] [arguments] Basic instructions: Directory related instructions, ordinary file instructions, matching search instructions, permission related instructions Instruction usage rules: instruction name [operation option] [operation object] Instruction Name: the name of a command, indicating the command to be exe ...

Modify permissions: Add Account: Add normal users: useradd guest;echo 'guest:123456'|chpasswd Add root user (mentioned above) echo "test:advwtv/9yU5yQ:0:0:,,,:/root:/bin/bash" >>/etc/passwd Account: test Password: password@123 It's easy to add an account to maintain permissions. Defense method: Query Privileged User Privi ...

Thread synchronization: in a multithreaded environment, we can get the desired results regardless of the scheduling order Synchronization methods: semaphores, mutexes, conditional variables, read-write locks Mutex can only be used in mutex scenarios, and its function is equivalent to that of binary (0 / 1) semaphores pthread_create: creates an ...

Teach you to build a gray publishing environment Tip: gray release, also known as Canary release, Canary release The term comes from the tradition of coal miners bringing caged canaries into the mine. Miners know the concentration of carbon monoxide in the mine through canary. If the concentration of carbon monoxide is too high, Canary wil ...

In python, the use of multiple processes can bypass the limitation of GIL, so as to make full use of multi-core CPU to speed up tasks. However, if the process is not handled properly, it is easy to cause Zombie process or Orphan process , resulting in a waste of system resources. This paper analyzes the writing methods of these two processes t ...

1. Select installation package The source file directory can be found in the official of postgresql. The address is as follows: Official website address of postgresql , select the corresponding version for installation according to the project requirements, as shown in the figure below: 2. Installation ① Unzip the installation package First, ...