computer science

SyncML

SyncML 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 SyncML rather than just read about it. In short: SyncML, or Synchronization Markup Language, was originally developed as a platform-independent standard for information synchronization. Established by the SyncML Initiative, this project has evolved to become a key component in data synchronization and device management.

Key takeaways

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

Reference excerpt

SyncML, or Synchronization Markup Language, was originally developed as a platform-independent standard for information synchronization. Established by the SyncML Initiative, this project has evolved to become a key component in data synchronization and device management. The project is currently referred to as Open Mobile Alliance Data Synchronization and Device Management. The purpose of SyncML is to offer an open standard as a replacement for existing data synchronization solutions; which have mostly been somewhat vendor, application, or operating system specific. SyncML 1.0 specification was released on December 17, 2000, and 1.1 on February 26, 2002. The most recent development with SyncML has been related to MDM(Mobile Device Management), which has seen active development in 2019. A SyncML message is a well-formed XML document that adheres to the document type definition (DTD), but which does not require validation.

Internals SyncML works by exchanging commands, which can be requests and responses. As an example:

the mobile phone sends an Alert command for signaling the wish to begin a refresh-only synchronization the computer responds with a Status command for accepting the request the phone sends one or more Sync command containing an Add sub-command for each item (e.g., phonebook entry); if the number of entries is large, it does not include the <Final/> tag; in the latter case, the computer requests to continue with an appropriate Alert message, and the mobile sends another chunk of items; otherwise, the computer confirms it received all data with a Status command Commands (Alert, Sync, Status, etc.) are grouped into messages. Each message and each of its commands has an identifier, so that the pair (MsgID, CmdID) uniquely determines a command. Responses like Status commands include the pair identifying the command they are responding to. Before commands, messages contain a header specifying various data regarding the transaction. An example message containing the Alert command for begin a refresh synchronization, like in the previous example, is:

The response from the computer could be an XML document like (comments added for the sake of explanation):

The transaction then proceeds with a message from the mobile containing the Sync command, and so on. This example is a refresh where the mobile sends all its data to the computer and nothing in the other way around. Different codes in the initial Alert command can be used to initiate other kinds of synchronizations. For example, in a "two-way sync", only the changes from the last synchronization are sent to the computer, which does the same. The Last and Next tags are used to keep track of a possible loss of sync. Last represents the time of the last operation of synchronization, as measured by each device. For example, a mobile may use progressive numbers (1, 2, 3, ...) to represent time, while the computer uses strings like "20140112T213401Z". Next is the current time in the same representation. This latter data is stored and then compared with Last in the next synchronization. Any difference indicates a loss of sync. Appropriate actions involving sending all data can be then taken to put the devices back in sync. Anchors are only used to detect a loss of sync; they do not indicate which data is to be sent. Apart from the loss-of-synchronization situation, in a normal (non-refresh) synchronization, each device sends a log of changes since the last synchronization.

SyncML client connectors and plugins

SyncML servers

1SAN = Server Alert Notification. This SyncML Push technology is based on definitions by the Open Mobile Alliance and extends the existing SyncML protocol specification by offering a method of server initiated synchronization.

SyncML hosted services

See also CalDAV CardDAV Critical Path SyncML Server iCalendar The SyncML Initiative Yahoo! Mobile and Yahoo! Calendar - Yahoo services offered in some countries that uses SyncML technology.

References

Worked examples

Example 1 — a first encounter with SyncML

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

In research: SyncML 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 SyncML 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: SyncML is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer standards, Open formats, SyncML, so understanding it makes those chapters shorter.
In everyday life: Look for SyncML 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 SyncML in 20 minutes

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

Frequently asked questions

What is SyncML in simple terms?

Why does SyncML 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 SyncML?

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 SyncML.