Linux

1 DMA ConceptsDMA, by definition, refers to the direct data-to-read operation between the device and memory, memory, and external storage devices without the need for CPU involvement. 2 DMA Principle DMA transmission needs to be carried out by the

PWD View current work pathCD into a folder ... Switch to Parent directory/switch to the root directoryLs-l view in long format that-A view information for all subdirectories and files, hidden files can also be viewed-D View the properties of the

List system disksFdisk-lThere are no disks used/dev/xvdbWorking with disk changesFdisk/dev/xvdbAt this point you can enter the command to disk operationCommand (M for help):Enter M to view the optional commands:Command ActionA toggle a bootable

1. Query the original installed OPENJDKRpm-qa |grep java rpm-qa |grep JDK2. Uninstall the original installed OPENJDKRPM-E--nodeps java-1.7.0-openjdk-1.7.0.45-2.4.3.3.el6.x86_643. Install the required JDKRPM-IVH jdk-7u55-linux-x64.rpm4. Configure the

First, downloadwget http://mirrors.hust.edu.cn/apache/lucene/solr/6.0.0/solr-6.0.0-src.tgzSecond, decompressionTAR-ZXVF solr-6.0.0-src.tgzNote:1. The. tgz file and the. tar.gz file are the same. Packed files that are compressed. tar package the file,

Each process has a different user address space, and the data exchange between processes must be done by opening up buffers in the kernel for data sharing. PipelinePiping is the most basic IPC mechanism, created by the pipe function:int

Buffered I/O and non-buffered I/OFile read and write mainly involves the following five operations: Open, close, read, write, locate. In a Linux system, two sets of APIs are provided, Set is C standard Api:fopen, fclose, Fread, fwrite,

Basic conceptsThe signal is a common concept in Linux, for example, we interrupt the foreground process by pressing CTRL + C, and ending the process through the kill command is done through the signal. The following is an example of CTRL + C for a

This article summarizes some of the techniques used in the previous commands:(1) mkdir Create catalog fileIn front of the main used to create a single file, you can actually batch create files directory.(2) rmdir Delete empty file directory, cannot

One, add diskFirst we add a disk I'm running on an Oracle VM VirtualBox virtual machine and choose to add a new disk when the system shuts downAfter adding the disk boot system, we first switch to the root user and the next operation requires root

RaidPerformance of disks 1.定位 2.旋转 3.命令队列 4.数据库传输HBA: Host-based adapterRaid:redundent array of inexpensive Disks inexpensive disk arrayIndependent Standalone disk arrayLevel: Only used to identify the different ways of disk composition, can

Let's start by explaining why the kernel divides interrupts into the upper and lower partsBecause the interrupt itself interrupts normal program execution, task scheduling cannot be performed in the interrupt, so the interrupt needs to be returned

1.set     environment variables: Used to define bash's working characteristics, save the current session's properties information          Show all environment variables: Export ,env ,printenv    2.bash profile      Profile: Provides configuration

Today, when writing code, inadvertently found that after using Vim to edit a file, the path will appear under the same name, but the last with a wave number of files.As an obsessive-compulsive disorder, I see the existence of this kind of document

I am also a small white, previously published in Win QT program feel very easy,release, to the directory run EXE file, the hint of what DLL to copy what DLL to the directory is good. Linux is roughly the same, but there are some differences.1.linux

Here simply write a knob drive, still need to continue to improve.#include #include #include #include #include #include #include #include #define KNOD_PIN1 56#define knod_pin2 55struct input_dev *input_dev;struct Work_ struct

ThreadSometimes, we need to run multiple control processes at the same time in one foundation. For example: A graphical interface of the download software, in the process of downloading tasks, but also must respond to the interface of the task of

Linux automatic synchronization server time and linux synchronization serverIntroduction When a Linux server runs for a long time, there will be some errors in the system time. This article will introduce how to synchronize the server time with the

MySQL master-slave synchronization principle deployment [Switch], mysql master-slave principle deployment I. Role of master and slave:1. It can be used as a backup method.2. read/write splitting to relieve the pressure on a databaseIi. MySQL

Linux chmod and chown command usage Linux chmod and chown command usage I. chown command Purpose: Change the owner or group of a file. The command is composed of the word change owner. Example: 1. Change the file owner: Chown jim program. c The