computer science

Rdate

Rdate 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 Rdate rather than just read about it. In short: On Unix-like operating systems, rdate is a tool for querying the current time from a network server and, optionally, setting the system time. Rdate uses the Time Protocol.

Key takeaways

Rdate 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 Rdate to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Rdate from memory before moving on to harder problems.

Reference excerpt

On Unix-like operating systems, rdate is a tool for querying the current time from a network server and, optionally, setting the system time. Rdate uses the Time Protocol. The Time Protocol is generally considered obsolete and has been replaced by the Network Time Protocol (NTP). When used to set the local system time, rdate operates by changing system time immediately to the time and date returned by the server. Abrupt changes of clock settings have been found to cause problems for software relying on timing. This led to the development of the Network Time Protocol, which gradually changes the system time and does not skip ticks. Due to the problems described above, rdate is generally used only on systems where NTP is not available, or in specialized circumstances where it is required that system time be set correctly as soon as possible during initial setup, before services which may be vulnerable to abrupt time-changes have started.

Worked examples

Example 1 — a first encounter with Rdate

Start with the simplest possible case. Write down what Rdate 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 Rdate 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 Rdate 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 Rdate

In research: Rdate 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 Rdate 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: Rdate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Internet Standards, Internet protocols, Network time-related software, so understanding it makes those chapters shorter.
In everyday life: Look for Rdate 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 Rdate in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Rdate 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 Rdate out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Rdate in simple terms?

On Unix-like operating systems, rdate is a tool for querying the current time from a network server and, optionally, setting the system time. Rdate uses the Time Protocol.

Why does Rdate 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 Rdate?

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 Rdate.