computer science

Sailfish OS

Sailfish OS 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 Sailfish OS rather than just read about it. In short: Sailfish OS is an operating system for mobile phones developed by Jolla. It is Linux-based with AppSupport, a proprietary compatibility layer for Android and custom user interface by Jolla.

Key takeaways

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

Reference excerpt

Sailfish OS is an operating system for mobile phones developed by Jolla. It is Linux-based with AppSupport, a proprietary compatibility layer for Android and custom user interface by Jolla. The OS first shipped with the original Jolla Phone in 2013; while its sale stopped in 2016, it was supplied with software updates until the end of 2020. It also shipped with Jolla Tablet in 2015 and from other vendors licensing the OS. The OS is ported by community enthusiasts to third-party mobile devices including smartphones and tablet computers. Sailfish OS is mostly used for mobile phones and tablets.

History and development The OS is an evolved continuation of the Linux MeeGo OS previously developed by Nokia and Intel which itself relies on combined Maemo and Moblin. This base is extended by Jolla with a custom user interface and default applications. The User Interface is highly based on gestures and pulley menus.

Software architecture The Sailfish OS and the Sailfish software development kit (SDK) are based on the Linux kernel and a standard Linux stack. Sailfish OS includes a multi-tasking graphical shell called "Lipstick" built with Qt by Jolla on top of the Wayland display server protocol. It uses standard Linux middleware like Systemd, Pulseaudio and Qt. Glibc is the included C Library. The first Jolla Phone in 2013 used Btrfs for the filesystem, afterwards Ext4 has been used. RPM is used as a package manager with PackageKit and Zypper for dependency resolving. For connectivity ConnMan is used to manage network connections. wpa_supplicant is used for wifi while Bluez is used for Bluetooth. oFono is used for telephone calls with VoLTE available only for the Sony Xperia 10 II and III and Jolla Phone (2026). Positioning is provided for with GPS and geoclue/beaconDB. For command-line access, Dash from BusyBox is installed by default, while Bash is also available. For remote access, SSH can be enabled in the settings, while root access is also possible. For development, there is GCC, LLVM, Autotools, Make and Meson. Included languages are Python, Ruby, Perl and Rust. For Game development, SDL is available. The default IDE is Qt Creator. Jolla uses free and open-source graphics device drivers while the Hybris library allows use of proprietary drivers for Android. Theming is done with Ambiences, which support images, colors and optionally ringtones. The Gallery app can create an Ambience from a single image. Some key components of Sailfish OS have been licensed proprietary by Jolla from the start and ever since (as of Sailfish OS 5.0 in February 2025). Since September 2025 some closed parts of Sailfish OS have been open sourced, with the announcement that more parts are to be followed. Firejail (Sailjail) is used for security sandboxing of native applications since version 4.0.1 in 2021. Sailfish OS can run some Android applications through a proprietary compatibility layer. It is running in an LXC container since Sailfish OS 3.0.1 from January 2019. Passthrough support for audio and bluetooth (since Sailfish 5.1 from 2026) is available.

Targeted device classes Sailfish is targeted at mobile devices. Sailfish can be used as a complete general-purpose Linux OS on devices including in vehicle infotainment (IVI), navigation, smart TV, desktops and notebooks, yachts, automotive, e-commerce, home appliances, measuring and control equipment, smart building equipment, etc. See the Devices section for devices that run the Sailfish OS.

Sailfish OS SDK The Sailfish OS SDK was announced at the Slush Helsinki conference in 2012, and the alpha was published in February 2013. The SDK, installation and coding tutorials are available for free download from the Documentation website despite the overall license not being open source. Sailfish SDK uses Qt with the Qt Creator IDE for development. It uses Virtualbox for the build engine, while there is also emulation available. It's available for Linux, MacOS and Windows hosts (all 64bit). Docker can be used instead of Virtualbox, but is only available for a Linux host. Targets for building are ARM in 64bit (aarch64) and 32bit (armv7hl) and Intel in 32bit (i486). For hardware development there is a Platform SDK and a Hardware Adaptation Development Kit.

Application programming interfaces Sailfish OS uses open source Qt APIs (Qt 5, QtQuick 2 etc.) and a proprietary Sailfish Silica for the UI. Standard Linux APIs are provided. Sailfish Browser is the default web browser based on Gecko and using embedlite, a lite-weight embedding API from Mozilla. It's available under the MPL-2.0 license.

Software overview

UI supported human languages Officially Jolla declares supporting the following 14 languages for the user interface: Danish, German, English (UK), Spanish, French, Italian, Norwegian, Polish, Portuguese, Finnish, Swedish, Russian, Chinese (mainland), and Chinese (Hong Kong). For each of them, the OS has a dedicated keyboard. There are a few more languages which are unofficially supported by community freelancers not under control by Jolla, hence more than 20 languages are supported in total. Additional languages can be installed by skilled users due to the Linux architecture.

Public "Early access" for beta testers and developers After positive experiences with pushing early updates to a small group of opt-in users for Sailfish Update 9 and for the connectivity hotfix, Jolla has allowed all interested parties to try a new version of Sailfish OS about 1–2 weeks before official release, in a program called "Early access". It is expected to be useful for developers and technically minded users, and a step towards more community integration into the Sailfish release process, including improvement of quality by identifying critical issues which only show up in certain environments or device setups, before rolling the update out to the wider user audience. As an added bonus, it provides a window for developers to test their applications on new releases of Sailfish OS. Basic details about the early access update:

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Sailfish OS

Start with the simplest possible case. Write down what Sailfish OS 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 Sailfish OS 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 Sailfish OS 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 Sailfish OS

In research: Sailfish OS 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 Sailfish OS 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: Sailfish OS is common in secondary-school and first-year university syllabi. It links to neighbouring topics ARM operating systems, Embedded Linux distributions, Finnish brands, so understanding it makes those chapters shorter.
In everyday life: Look for Sailfish OS 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 Sailfish OS in 20 minutes

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

Frequently asked questions

What is Sailfish OS in simple terms?

Sailfish OS is an operating system for mobile phones developed by Jolla. It is Linux-based with AppSupport, a proprietary compatibility layer for Android and custom user interface by Jolla.

Why does Sailfish OS 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 Sailfish OS?

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 Sailfish OS.