HVAC equipment HS code mapping

1. Multi-machine two-take-two redundancy structure"Two take two" refers to the integration of two sets of CPUs on a subsystem, and the two sets of CPUs are strictly synchronized and compared in real time. Only when the two machines run consistently can the calculation results be output to the outside world. "Two-to-two" refers to the use of two identical sets of two-to-two subsystems to form a dual-machine concurrent or hot standby system.

2. Two squares two takes two; two takes two sets of hardware work at the same time. After comparing the inside of the two sets, take one of the two sets, one of the two sets of faults, and the other set can also work normally; three take two, compare three sets of hardware at the same time, and take the same two sets. If one set fails, the whole set of systems cannot work. , this is not convenient for on-site maintenance.

3. The two-to-two system consists of four computers to form two subsystems, one of which serves as the host output control instruction, and the other is a hot standby. Sub-systemThe two computers in Tongzhong execute a set of programs with the same code, and then compare the calculation results, and output the results if they are consistent.

[Railway Signal Knowledge] Redundant Structure with Emergency

In order to improve the reliability and security of the system, most computer chains adopt redundant structures. Its redundancy method is divided into three categories: dual-machine hot standby, two-to-two systems.

Passing signal machine equipped with a allowable signal, allowing the signal to display a blue light: allowed the train does not stop when the signal machine shows a red light, passes at a speed of no more than 20 km/h, runs to the next pass signal machine, and is ready to stop at any time. Cut off the signal machine: a red light: the train is not allowed to cross the signal machine.

Railway transport shippers shall not commit the following acts when consigning goods, luggage and parcels: (1) concealing or falsely reporting the name and nature of the goods; (2) carrying dangerous goods in ordinary goods, or carrying prohibited goods in dangerous goods; (3) concealing or falsely reporting the weight of the goods or loading and packing more than the regulations Weight; (4) Other acts that endanger the safety of railway transportation.

What are the trivia about high-speed railways? First of all, from the facilities: the high-speed railway uses a newly built high-speed railway line, which adopts a slag-free track based on viaducts, which can ensure the stability and durability of the line and create good basic conditions for the high-speed operation of the high-speed railway.

The following is the handwritten content of railway safety knowledge (general 5 articles) that I have sorted out for you. Welcome to learn from it and refer to it. I hope it will be helpful to you.Handwritten newspaper content of railway safety knowledge Chapter 1 Pedestrians are not allowed to walk, sit and lie on the railway.

What does dual-machine hot standby mean

1. Two servers perform the same service together. One of the servers is used as the main server and the other server is used as the backup server. When the main server fails, the backup server will automatically take over the work of the main server to ensure the uninterrupted operation of the service.

2. Dual-machine hot backup refers to the hot backup (or high availability) of two servers in a high-availability system. Because the high availability of the two machines is more widely used in China, it is called dual-machine hot backup. Cold standby refers to two servers, one running and the other not running as backup.

3. Dual-machine hot standby: For the same application, it is always the host application starts and the standby application stops. One main and one backup mode. Load balancing: two/multiple servers work on the same application system at the same time and share the load pressure. This is the main difference.

4. In a narrow sense, dual-machine hot standby refers to server hot standby based on active/standby. Server data includes database data written to two or more servers at the same time, or using a shared storage device. Only one server is running at the same time.

5. Dual-machine hot standby: that is, for important services, use two servers to back up each other and execute the same service together.

6. Virtual machines will have more advantages. The two-machine hot standby is the same.Configured server + shared storage, install the operating system and database application on the two servers, and save the background database on the storage. It can improve the reliability of the system.