computer science

XULRunner

XULRunner 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 XULRunner rather than just read about it. In short: XULRunner is a discontinued, packaged version of the Mozilla platform to enable standalone desktop application development using XUL, developed by Mozilla. It replaced the Gecko Runtime Environment, a stalled project with a similar purpose.

Key takeaways

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

Reference excerpt

XULRunner is a discontinued, packaged version of the Mozilla platform to enable standalone desktop application development using XUL, developed by Mozilla. It replaced the Gecko Runtime Environment, a stalled project with a similar purpose. The first stable developer preview of XULRunner was released in February 2006, based on the Mozilla 1.8 code base. Mozilla stopped supporting the development of XULrunner in July 2015. XULRunner was a "technology experiment", not a shipped product, meaning there were no official XULRunner releases, only stable builds based on the same code as a corresponding Firefox release.

Software architecture XULRunner is a runtime that can be used to bootstrap multiple XUL + XPCOM applications that are equal in capabilities to Firefox and Thunderbird. XULRunner stores a variety of configuration data (bookmarks, cookies, contacts etc.) in internally managed SQLite databases, and even offer an add-on to manage SQLite databases.

Uses

Mozilla Firefox, Mozilla Thunderbird, Nightingale, Songbird, Flickr Uploadr, SeaMonkey, Conkeror, Sunbird, Miro, Joost, and TomTom Home 2.0 ran on XULRunner. Starting with version 3.0, Mozilla Firefox uses a "private" XULRunner, meaning the framework is installed locally in the application directory. Kiwix, an offline browser for Wikipedia and Project Gutenberg, used XULRunner until 2017. The Google AdWords Editor used XULRunner until 2010, as did Evergreen ILS, an open-source library automation system. The fourth version of the video game series Simon the Sorcerer, Simon the Sorcerer 4: Chaos Happens, uses XULRunner. In addition, the XULRunner package provided access to ActiveX Control functionality previously found in a (now defunct) third-party ActiveX Control built off the Mozilla source code. Applications using this application programming interface (API) may have function with XULRunner installed and registered. Starting with Lotus Notes version 8.5.1, IBM deployed XULRunner to provide Notes client support for XPages applications. XULJet was an open-source JavaScript framework for XULRunner.

Deprecation In January 2014, dropping XULRunner support was discussed by Mozilla developers. In July 2015, Mozilla stopped supporting the development of XULrunner, and the community page has been taken down. As of the beginning of 2016, it had been dropped from the package database of most Linux distributions, including Gentoo, Debian, and Ubuntu. XULRunner can still be installed separately, and many XULRunner-dependent applications can be switched over fairly easily. Also developing and running XULRunner apps is still possible through Firefox as well as previous or custom builds of XULRunner. However, its disappearance has caused some dependent packages to be removed from package databases. Despite this deprecation, the latest versions of Firefox and Thunderbird can still run XULRunner applications with the -app command line argument.

Illustrations

Worked examples

Example 1 — a first encounter with XULRunner

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

In research: XULRunner 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 XULRunner 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: XULRunner is common in secondary-school and first-year university syllabi. It links to neighbouring topics Free software programmed in C++, Free system software, Markup languages, so understanding it makes those chapters shorter.
In everyday life: Look for XULRunner 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 XULRunner in 20 minutes

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

Frequently asked questions

What is XULRunner in simple terms?

Why does XULRunner 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 XULRunner?

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 XULRunner.