Of interprocess communication -- anonymous pipeline

1. Overview Anonymous pipeline is used for the communication between related processes. The word of pipeline is like its name. It is like laying a pipeline between two processes, and the processes interact with each other through the pipeline. The nameless pipeline has no name. It is created by the pipe or pipe2 function. The corresponding one ...

Posted by FluxNYC on Tue, 19 Apr 2022 09:05:37 +0300

awk command of Linux three swordsmen

awk is a pattern scanning and processing language. It is a very powerful document editing tool. It can process files not only in behavior units, but also in columns. Let's learn it from the following three aspects: Format explanation Simple practice Advanced practice 1, Format explanation 1. Command format awk [parameter] '[action]' [file na ...

Posted by garydt on Tue, 19 Apr 2022 07:58:08 +0300

Initial Embedded linux 3-5-I2C

Personal blog address: Initial Embedded linux 3-5-I2C I2C Protocol and SMBus Protocol Since I am fairly familiar with the I2C protocol, there is no explanation of the I2C protocol itself in my notes. Here are two blogs to learn about the I2C and SMBus protocols: Understanding the I2C Bus SMBus Quick Start Guide i2c-tools Use i2c-tools to e ...

Posted by kritikia on Mon, 18 Apr 2022 20:25:11 +0300

Explain knapsack problem in depth: one of every five dynamic programming in the interview is knapsack model

❝ Author: Gong Shui Sanye. Now Microsoft engineer (Java back-end direction), retired OIer. For more information about the interview algorithm, click here "Attention~ Reprint should pay attention to the official account contact list. ❞ preface How to reduce the complexity of knapsack space from $o to $0 (c) $. On the basis of ...

Posted by fuzzy1 on Mon, 18 Apr 2022 19:48:47 +0300

Brief analysis of deadline scheduler

dl queue structure struct dl_rq { /* runqueue is an rbtree, ordered by deadline */ struct rb_root_cached root; unsigned long dl_nr_running; #ifdef CONFIG_SMP struct { u64 curr; //deadline value of the current running task u64 next; //Value of task deadline } earliest_dl; unsigned long dl_nr_migratory; int overloaded; stru ...

Posted by timbr8ks on Mon, 18 Apr 2022 15:06:09 +0300

Advanced learning of operation and maintenance: MySQL single table query

MySQL third job MySQL single table query job The material is as follows: DROP TABLE IF EXISTS `course`; CREATE TABLE `course` ( `cs_id` int(11) NOT NULL COMMENT 'course number', `cs_name` varchar(50) NOT NULL COMMENT 'course name', `cs_credit` tinyint(255) unsigned DEFAULT NULL COMMENT 'course credit', `cs_type` char(12) DEFAULT NULL CO ...

Posted by shak123 on Mon, 18 Apr 2022 10:16:06 +0300

Semaphore, mutex lock, spin lock

preface Semaphore: a lock mechanism used to coordinate mutually exclusive access to critical resources between processes. To ensure that a shared resource is not accessed by multiple processes at the same time. Mutex: a semaphore with an initial value of 1 Spinlock: similar to a mutex, but when resources cannot be obtained, the mutex ker ...

Posted by rougue on Mon, 18 Apr 2022 09:19:55 +0300

Linux Network - remote access control (SSH service)

1, SSH Remote Management 1.1 definition of SSH SSH (Secure Shell) is a secure channel protocol, which is mainly used to realize the functions of remote login and remote replication of character interface;SSH protocol encrypts the data transmission between the communication parties, including the user password entered when the user logs in ...

Posted by webdzine on Mon, 18 Apr 2022 08:57:06 +0300

Mysql basic command notes

MYSQL Foundation 1.DDL statement Creation and deletion of database / table --Create database create database Database name charset=utf8 --Delete database drop database test1 --Create table CREATE TABLE tablename( column_name_1 column_type_1 constraints, column_name_2 column_type_2 constraints,) --Delete table DROP TABLE tablename c ...

Posted by SevereSoldier on Mon, 18 Apr 2022 01:54:34 +0300

HA High Availability Configuration and Failover in Database

1. Overview of MHA MHA (MasterHigh Availability) is an excellent set of software for failover and master-slave replication in MySQL highly available environment.The emergence of MHA is to solve the MySQL single point problem.During MySQL failover, MHA can automatically complete the failover within 0-30 seconds.MHA ensures maximum data cons ...

Posted by expostfacto on Sun, 17 Apr 2022 20:22:33 +0300