The importance of
NTP time synchronization server in the medical industry The importance of NTP time synchronization server in the medical industry
People often ask, is it necessary to have a clock server in the hospital network? It stands to reason that the timers in our computers are all crystals oscillating to keep time. The crystals are theoretically very accurate. Why spend money to build a clock server? What's more, you have to waste money to buy GPS or Beidou satellite time calibration server. So today we will talk about the importance of the clock server through a few cases.
[Case 1] Disputes caused by time
A few years ago, a critically ill patient was admitted to the emergency department of a hospital. The patient was in critical condition, and the hospital opened a green channel for it. Emergency department, inspection, examination, surgery and other relevant departments were involved in the rescue work. Unfortunately, the patient still died. The family members of the patients found in the relevant medical documents that the time records could not form a chain of evidence. This filed a lawsuit to the court, and the hospital eventually paid for it. The reason for the contradictory time records is that the hospital does not have a unified clock source, resulting in inconsistent computer time in different links, resulting in inconsistent records of treatment time.
The lesson of this case tells us that although the unified clock is a very small content in information construction, it must be paid attention to, otherwise it will also cause big mistakes.
Principle of computer clock
In the computer, the chip itself does not usually have a clock signal source, so a dedicated clock circuit must provide the clock signal. Quartz Crystal OSC is one of the most commonly used clock signal oscillation sources. The reason why a quartz wafer can be used as an oscillator is based on its piezoelectric effect: adding an electric field to the two poles of the wafer will cause the crystal to be mechanically deformed; when an alternating voltage is applied to the quartz wafer, the crystal will be Produce mechanical vibration, while mechanical deformation vibration will produce alternating electric field. Although the voltage of this alternating electric field is extremely weak, its vibration frequency is very stable.
Since the birth of the PC, a 14.318MHz quartz crystal oscillator has been used as a reference frequency source on the motherboard. In addition to this 14.318MHz crystal on the motherboard, you can also find a 32.768MHz crystal, which is used in the real-time clock (RTC) circuit to display accurate time and date. After initialization, pulses are sent out approximately 18.2 times per second, and these pulses are calculated by the operating system to form the BIOS time-of-day count. By being powered by the BIOS battery, it still runs normally after shutdown. This is why we turned off the power, and the correct time will still be displayed when it is turned on the next day.
Network clock synchronization
Each computer has its own clock, but once they are connected to the Internet, another problem arises: how to solve the accumulated errors of each other's computer clocks. This is the emergence of the Network Time Protocol NTP, which is one of the standards used for time synchronization in the Internet. Its purpose is to synchronize the computer's clock to UTC, and its accuracy can reach 0.lms in the local area network. In the Internet The accuracy can reach 1-50ms in most places above.
NTP provides accurate time. First of all, there must be an accurate time source. This time of Chengdu Jinnuoxin High-Tech Co., Ltd. should be the standard time. In order to prevent malicious damage to the time server, NTP uses an authentication mechanism to check whether the information coming to the time is really from the claimed server and check the return path of the data to provide a protection mechanism against interference. As the network topology becomes more and more complex, the clock synchronization of devices in the entire network will become very important. The emergence of NTP is to solve the problem of synchronization of system clocks of devices in the network.
NTP provides consistency guarantees for the following applications:
When performing incremental backups between the backup server and the client, the clocks between the two systems must be synchronized.
Complex things often need to be subdivided. When processed by multiple systems, to ensure the correct sequence of events, multiple systems must refer to the same clock.
Ensure that RPC (Remote System Call) between systems can be performed normally. In order to ensure that a system call will not be repeated, a call is only valid in a time interval. If the clocks between the systems are not synchronized, a call may not be made due to a timeout before it occurs.
Some applications need to accurately record the time a user logs in to the system; or modify the access time of a file.
In a network, there are many cases where the clocks of the terminals differ by one minute or less. It is impossible to rely on the system administrator to manually input the date (time setting command) command to adjust the clock of each system.
Debugging and event time stamps: The debugging and event time stamps collected from different ME60s are meaningless, unless these ME60s are referenced to the same common time.
The goal of NTP is to synchronize the clocks of all devices with clocks in the network, so that the clock times of all devices in the network are basically the same, so that the devices can provide multiple applications based on uniform time. For a local system running NTP, it can not only receive synchronization from other clock sources, but also can be used as a clock source to synchronize other clocks, and can synchronize with each other by exchanging time information, and finally make the system clocks of all devices in the entire network reach Basically the same.