computer science

Time server

Time server is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Time server rather than just read about it. In short: A time server is a server computer that reads the actual time from a reference clock and distributes this information to its clients using a computer network. The time server may be a local network time server or an internet time server.

Key takeaways

Time server belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Time server to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Time server from memory before moving on to harder problems.

Reference excerpt

A time server is a server computer that reads the actual time from a reference clock and distributes this information to its clients using a computer network. The time server may be a local network time server or an internet time server. The most important and widely used protocol for distributing and synchronising time over the Internet is the Network Time Protocol (NTP), though other less-popular or outdated time protocols continue in use. A variety of protocols are in common use for sending time signals over radio links and serial connections. The time reference used by a time server could be another time server on the network or the Internet, a connected radio clock or an atomic clock. The most common true time source is a GPS or GPS master clock. Time servers are sometimes multi-purpose network servers, dedicated network servers, or dedicated devices. All a dedicated time server does is provide accurate time. An existing network server (e.g. a file server) can become a time server with additional software. The NTP homepage provides a free and widely used reference implementation of the NTP server and client for many popular operating systems. The other choice is a dedicated time server device. The term "stratum" is used to label the closeness to a central or high quality time server. The stratum indicates the place of a particular time server in a hierarchy of servers. The scale is 1 to 15 where 1 is the most accurate and likely a highly specialized physical hardware device. Some time clients will reject a time update from a server whose stratum is too high, and most will prefer low strata time sources to higher ones. This can be a pitfall for administrators setting up an in-house time server with no true time source. Commercial implementations of stratum-1 and stratum-2 servers are available from various manufacturers.

See also Network Time Protocol Inter-range instrumentation group time codes (IRIG) IEEE 1344 IEEE 1588 NMEA 0183

References

NTP FAQ for detailed descriptions of reference clocks used by a computer timeserver.

External links Official site of the Network Time Protocol (NTP) Pool of public NTP Time Servers ntp.org list of NTP Servers

Illustrations

Worked examples

Example 1 — a first encounter with Time server

Start with the simplest possible case. Write down what Time server claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Time server before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Time server ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Time server

In research: Time server appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Time server in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Time server is common in secondary-school and first-year university syllabi. It links to neighbouring topics Network time-related software, Servers (computing), Time measurement systems, so understanding it makes those chapters shorter.
In everyday life: Look for Time server outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Time server in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Time server means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Time server out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Time server in simple terms?

Why does Time server matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Time server?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Time server.