science

Portable Contacts

Portable Contacts is a 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 Portable Contacts rather than just read about it. In short: Portable Contacts is an open protocol to make it easier for developers to give users a secure way to access the address books and friends lists they have accrued online. The goal of the project is to increase data portability by creating a common and open specification to bridge proprietary contacts APIs such as Google's GData Contacts API, Yahoo's Address Book API, and Microsoft's Live Contacts API.

Key takeaways

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

Reference excerpt

Portable Contacts is an open protocol to make it easier for developers to give users a secure way to access the address books and friends lists they have accrued online. The goal of the project is to increase data portability by creating a common and open specification to bridge proprietary contacts APIs such as Google's GData Contacts API, Yahoo's Address Book API, and Microsoft's Live Contacts API. It combines OAuth, XRDS-Simple and a wire-format based on vCard harmonized with schema from OpenSocial. The editor of the Portable Contacts standard was Joseph Smarr of Plaxo and the project was co-maintained by Chris Messina. Portable Contacts has been used by services such as Google Contacts, Windows Live Messenger Connect, as well as other specification such as OStatus.

References

External links Portable Contacts homepage (archive, original site died, later cloned by a spammer) Portable Contacts 1.0 specification (archive)

Worked examples

Example 1 — a first encounter with Portable Contacts

Start with the simplest possible case. Write down what Portable Contacts claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In 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 Portable Contacts 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 Portable Contacts 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 Portable Contacts

In research: Portable Contacts appears in 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 Portable Contacts 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: Portable Contacts is common in secondary-school and first-year university syllabi. It links to neighbouring topics Application programming interfaces, Business cards, Internet stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Portable Contacts 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 Portable Contacts in 20 minutes

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

Frequently asked questions

What is Portable Contacts in simple terms?

Why does Portable Contacts matter?

Because it connects several 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 Portable Contacts?

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 Portable Contacts.