Time server facts for kids
A time server is like a special computer that knows the exact time. It gets this super accurate time from a very precise clock, like an atomic clock or a GPS clock. Then, it shares this correct time with other computers on a network or the internet. Think of it as the official timekeeper for all the other devices!
The main way time servers share time is using something called the Network Time Protocol (NTP). A protocol is just a set of rules that computers use to talk to each other. NTP is the most popular way to make sure all computers have the same time, which is super important for many things they do.
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What is a Time Server?
A time server is a computer that makes sure other computers have the right time. It's like a central clock for a group of computers. This can be for computers in a school, an office, or even across the entire internet.
Why Computers Need Accurate Time
Having the correct time is really important for computers. Here's why:
- Scheduling: Computers need to know the exact time to schedule tasks, like sending emails or running programs at specific moments.
- Logging: When something happens on a computer, it records the time. If times are different, it's hard to know the order of events.
- Security: Many security systems rely on accurate time to make sure information is safe and secure.
- Coordination: When many computers work together, they need to be perfectly in sync. Imagine trying to play a multiplayer game if everyone's computer had a different time!
How Time Servers Get the Time
Time servers don't just guess the time. They get it from very reliable sources.
Reference Clocks
The most accurate time sources are called "reference clocks." These can be:
- Atomic Clocks: These are incredibly precise clocks that measure time using the vibrations of atoms. They are the most accurate clocks known!
- GPS Clocks: Many time servers get their time from GPS satellites orbiting Earth. These satellites have very accurate clocks on board.
- Other Time Servers: Sometimes, a time server gets its time from another, even more accurate time server on the internet.
The main way time servers share time is through the Network Time Protocol (NTP).
Network Time Protocol (NTP)
NTP is like the universal language for time. It allows computers to ask a time server for the current time and then adjust their own clocks to match. It's designed to be very accurate, even over the internet. While NTP is the most common, there are a few older or less common ways computers used to share time.
Types of Time Servers
Time servers can come in different forms:
- Dedicated Devices: Some time servers are special devices built just to provide accurate time. They are often very reliable.
- Software on Existing Servers: You can also turn a regular computer server (like one that stores files) into a time server by adding special software. The NTP website offers free software that can do this.
Understanding "Stratum" Levels
When talking about time servers, you might hear the word "stratum." This word describes how close a time server is to the original, super-accurate time source.
What Stratum Means
Think of stratum as a level or a rank:
- Stratum 1: These are the most accurate time servers. They are directly connected to a very precise reference clock, like an atomic clock or a GPS clock.
- Stratum 2: These servers get their time from Stratum 1 servers. They are like a copy of a copy, but still very accurate.
- Higher Stratum Numbers: The higher the stratum number (like 3, 4, and so on, up to 15), the further away the server is from the original, most accurate time source.
Computers usually prefer to get their time from servers with lower stratum numbers because they are more accurate. If a server's stratum number is too high, some computers might not trust its time.
See also
- Network Time Protocol
- Inter-range instrumentation group time codes (IRIG)
- IEEE 1344
- IEEE 1588
- NMEA 0183
