Programmer Group

1. Users & User Groups Linux is a multi-user and multi-task operating system. The Linux system supports multiple users to log on at the same time. Different users can perform different tasks within their permissions without affecting each other. Corresponding relationships between users and user groups: One-to-one: A user can exist in a ...

1, Principle of Chinese character lattice font (1) Chinese character coding 1. Location code    it is stipulated in the national standard GD2312-80 that all national standard Chinese characters and symbols are distributed in a square matrix with 94 rows and 94 columns. Each row of the square matrix is called an "area", numbe ...

Tip: after the article is written, the directory can be generated automatically. Please refer to the help document on the right for how to generate it catalogue Tip: Here you can add the general contents to be recorded in this article: For example, with the continuous development of artificial intelligence, machine learning technology i ...

1, Basic concepts Session: a session contains multiple requests and responses One session: the browser sends a request to the server resource for the first time, and the session is established until one party disconnects (the browser or client is closed) Function: share data between multiple requests within a session Method: Clien ...

1, What is a form   The form is mainly responsible for the data collection function in the web page. The < form > tag in HTML is used to collect the information entered by the user, and submit the collected information to the server for processing through the submission operation of the < form > tag Form components: Form lab ...

reference resources TCP/IP network programming Yin Shengyu Multicast and broadcasting Multicast Multicast data transmission is based on UDP. The difference from the implementation of UDP server / client is that UDP data is transmitted to a single target, while multicast data is transmitted to a large number of hosts joining (registering) a ...

Nginx and Tomcat deployment We all know that Nginx has very high performance in high concurrency scenarios and processing static resources, but in actual projects, in addition to static resources, there are background business code modules. Generally, background business will be deployed on Web servers such as Tomcat, weblogic or websphe ...

After class questions 1-5 1. How many layers are the network communication protocols divided into? What are the problems solved by each layer? >>OSI layer 7 protocol   OSI seven layer network modelfunctionapplication layerDirectly provide services for the user's application processPresentation layerProvides a standard format for net ...

Recently, I was debugging the Linux kernel and tracking the startup process. It is found that before turning on mmu, the physical address can be used to output debugging information by losing data to the serial port Fifo. However, once the code runs to enable mmu, in the assembly stage, mmu only maps the physical memory and does not map io, so ...

Introduction Due to the need to write a java program and an existing c program (AFL) for local communication in the near future, the efficiency of sending data using udp is not very high. In addition, AFL itself uses shm to share the physical memory to obtain the execution path information of the subroutine to be tested, while the shared memor ...