HS code indexing for specialized products

List of contents of this article:

• 1, linux file system basics
• 2、Basic Knowledge of Six Major Systems of Equipment
• 3,HS code indexing for specialized products How to learn computer knowledge systematically?

Linux file system basics

Linux file systemA file is a collection of data. The file system contains not only the data in the file, but also the structure of the file system. The files, directories, soft connections and file protection information seen by all Linux users and programs are stored in it.

/ The entrance of the file system, the highest-level directory; /bin The commands required by the basic system are located in this directory, which are the commands required by the minimum system, such as: ls, cp, mkdir, etc. The files in this directory are executable and can be used by ordinary users.

LINUX has four basic file system types: ordinary files, directory files, connecting files and special files, which can be identified by the file command. ORDINARY FILES: SUCH AS TEXT FILES, C LANGUAGE METACODES, SHELL PINThis, binary executable files, etc. can be used with cat, less, more, vi, emacs to inspect the content, and use mv to change the name.

Let's first check the standard directory under the Linux system /bin The commands required by the basic system are in this directory, such as ls, cp, etc., which are all executable files in this directory.

/bin is used to store commands that ordinary users can execute. /Boot is used to store the files necessary for Linux startup, that is, the contents of the boot partition we established. /Dev is used to store the device files of the system. /Etc is used to store various configuration files of the system. /Home is used to store the main directory of each ordinary user in the system.

Mounting refers to separating a folder in the Linux file system and placing it on a certain partition. At this time, the mounted partition is called the mount point, and the file that records the file mounting settings is called fstab. Under the /etc/ directory, you can customize the mount according to the format.

Basic knowledge of the six major systems of equipment

The expansion circulation system mainly includes process fans, exhaust gas fans, tangent separators, expansion towers, cyclone dust collectors, air locks, etc. The reflow system mainly includes vibration cabinet, belt scale, belt conveyor, reflow cylinder, moisture meter, vibration groove, etc.

The first system: mining system The mining system mainly includes underground lighting equipment, mining area ventilation, coal transportation, etc. Among them, the wellDownlight electric equipment is one of the most basic equipment in mining. It is responsible for generating underground electricity to supply the operation of various equipment for mining production.

What systems are included in the basic equipment of the diesel generator set? Diesel generator sets mainly include six major systems, namely: (1) oil lubrication system; (2) fuel system; (3) control protection system; (4) cooling and heat dissipation system; (5) exhaust system; (6) start-up system.

How to learn computer knowledge systematically?

1. Basic operation. Be familiar with the basic operation of the computer. These can be done by reading books and reading the operating instructions. Familiarize yourself with the basic operation of the computer, and then study and learn more in-depth knowledge. Improve your ability to use computers.Typing speed.

2. Method/Steps: Understand the basic components of computers. Computers, also known as microcomputers, are composed of two parts: software and hardware. Familiar with the functions and roles of mouse, keyboard and other hardware on the computer. Go to the library to check materials and learn the most basic computer operation.

3. Familiar with the operating system: The key to learning to use a computer is to be familiar with the operating system. Familiarity with the Windows or Mac OS operating system allows you to use your computer to perform various tasks more efficiently.

4. Participate in training courses: Some universities or community institutions will provide free or paid computer training courses. You can sign up for these courses to systematically learn computer basics and skills. These courses usually include basic computer operation, Internet use, email, office software, etc.

5. Learn the basics of computers from scratch. Know how to turn on, shut down and restart the computer. The laptop power-on key is generally an independent key outside the keyboard, and the desktop is the largest button above the host; shutdown and restart is after the computer is turned on, the mouse click in the lower left corner of the desktop [ Start] can be realized.