computer science

Jog dial

Jog dial 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 Jog dial rather than just read about it. In short: A jog dial, jog wheel, shuttle dial, or shuttle wheel is a type of knob, ring, wheel, or dial which allows the user to shuttle or jog through audio or video media. It is commonly found on models of CD players which are made for disc jockeys, and on professional video equipment such as video tape recorders.

Key takeaways

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

Reference excerpt

A jog dial, jog wheel, shuttle dial, or shuttle wheel is a type of knob, ring, wheel, or dial which allows the user to shuttle or jog through audio or video media. It is commonly found on models of CD players which are made for disc jockeys, and on professional video equipment such as video tape recorders. More recently, they are found on handheld PDAs, and as the scroll wheel on computer mice. "Jog" refers to going at a very slow speed, whereas "shuttle" refers to a very fast speed. There are two basic types of wheels. One type has no stops and can be spun the entire way around, because it is a rotary incremental encoder. This type depends on tracking the actual motion of the dial: the faster it spins forward or back, the faster it fast-forwards or rewinds. Once the dial stops moving, the media continues playing or remains paused at that point. Another type has stops on either side, and often has three or so speeds which depend on how far it is turned. Once the wheel is released, it springs back to the middle position and the media pauses or begins playing again.

If the device is set or designed to pause after the wheel is used, the audio is often stuttered, repeating a small section over and over again. This is usually done by DJs using CDJs or DJ controllers, for the purpose of beatmatching, and is equivalent to an earlier turntablist DJ moving a phonograph record back and forth slightly to find the physical location of a starting beat within the groove. On the video, the pause is a freeze frame of the current video frame. Sony Corporation held a patent for a 5-way version of the jog dial. A 5-way jog dial allows up and down scrolling, right and left deflections, and a press-to-click action. Such jog dial was a feature of the Sony CLIÉ PDA series and Sony Ericsson P800, P900 and P910 smartphones. A 5-way jog dial has not been used by Sony or its subsidiaries since 2006.

See also iPod click wheel Dial box Jogcon

References

External links Media related to Jog dial at Wikimedia Commons

Illustrations

Worked examples

Example 1 — a first encounter with Jog dial

Start with the simplest possible case. Write down what Jog dial 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 Jog dial 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 Jog dial 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 Jog dial

In research: Jog dial 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 Jog dial 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: Jog dial is common in secondary-school and first-year university syllabi. It links to neighbouring topics Audio engineering, Computing input devices, Input/output, so understanding it makes those chapters shorter.
In everyday life: Look for Jog dial 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.

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How to study Jog dial in 20 minutes

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

Frequently asked questions

What is Jog dial in simple terms?

Why does Jog dial 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 Jog dial?

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 Jog dial.