HarmonyOS (HMOS) () is a
distributed operating system
A distributed operating system is system software over a collection of independent software, networked, communicating, and physically separate computational nodes. They handle jobs which are serviced by multiple CPUs. Each individual node holds a ...
developed by
Huawei
Huawei Technologies Co., Ltd. ( ; ) is a Chinese multinational technology corporation headquartered in Shenzhen, Guangdong, China. It designs, develops, produces and sells telecommunications equipment, consumer electronics and various smar ...
to collaborate and interconnect with multiple
smart devices
A smart device is an electronic device, generally connected to other devices or networks via different wireless protocols (such as Bluetooth, Zigbee, near-field communication, Wi-Fi, LiFi, or 5G) that can operate to some extent interactively and ...
on the
Internet of Things (IoT) ecosystem.
In its current
multi-kernel design, the operating system selects suitable kernels from the
abstraction layer for devices with diverse resources.
For IoT devices, the system is known to be based on
LiteOS
Huawei LiteOS was a lightweight real-time operating system (RTOS) developed by Huawei. It is an open source, POSIX compliant operating system for Internet of things (IoT) devices, released under a three-clause BSD license. Microcontrollers of di ...
kernel; while for smartphones and tablets, it is based on a
Linux kernel layer with
AOSP compatibility libraries to support legacy
APK apps, in addition to native HarmonyOS
HAP apps via the Ark Compiler.
The system includes a communication base DSoftBus for integrating physically separate devices into a virtual Super Device, allowing one device to control others and sharing data among devices with
distributed communication capabilities. It supports several forms of apps, including the apps that can be installed from
AppGallery on smartphones and tablets, installation-free Quick apps and lightweight Atomic Services accessible by users.
HarmonyOS was first used in
Honor
Honour (British English) or honor (American English; see spelling differences) is the idea of a bond between an individual and a society as a quality of a person that is both of social teaching and of personal ethos, that manifests itself as a ...
smart TVs in August 2019 and later used in Huawei
smartphones,
tablets and
smartwatches in June 2021.
History
Origins
Reports surrounding an in-house operating system being developed by Huawei date back as far as 2012. These reports intensified during the
Sino-American trade war, after the
United States Department of Commerce
The United States Department of Commerce is an executive department of the U.S. federal government concerned with creating the conditions for economic growth and opportunity. Among its tasks are gathering economic and demographic data for bus ...
added Huawei to its
Entity List in May 2019 under an indictment that it knowingly exported goods, technology and services of U.S. origin to Iran in violation of
sanctions. This prohibited U.S.-based companies from doing business with Huawei without first obtaining a license from the government. Huawei executive described an in-house platform as a "plan B" in case it is prevented from using
Android on future
smartphone
A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
products due to the sanctions.
Prior to its unveiling, it was originally speculated to be a
mobile operating system
A mobile operating system is an operating system for mobile phones, tablets, smartwatches, smartglasses, or other non-laptop personal mobile computing devices. While computers such as typical laptops are "mobile", the operating systems used on ...
that could replace Android on future Huawei devices. In June 2019, an Huawei executive told
Reuters
Reuters ( ) is a news agency owned by Thomson Reuters Corporation. It employs around 2,500 journalists and 600 photojournalists in about 200 locations worldwide. Reuters is one of the largest news agencies in the world.
The agency was esta ...
that the OS was under testing in China, and could be ready "in months", but by July 2019, some Huawei executives described the OS as being an
embedded operating system designed for IoT hardware, discarding the previous statements for it to be a mobile operating system.
Some media outlets reported that this OS, referred to as "Hongmeng", could be released in China in either August or September 2019, with a worldwide release in the second quarter of 2020. On 24 May 2019, Huawei registered "Hongmeng" as a
trademark
A trademark (also written trade mark or trade-mark) is a type of intellectual property consisting of a recognizable sign, design, or expression that identifies products or services from a particular source and distinguishes them from othe ...
in China. The name "
Hongmeng" () came from Chinese mythology that symbolizes primordial chaos or the world before creation. The same day, Huawei registered trademarks surrounding "Ark OS" and variants with the
European Union Intellectual Property Office
The European Union Intellectual Property Office (EUIPO; french: links=no, Office de l'Union européenne pour la propriété intellectuelle), founded in 1994, is the European Union Agency responsible for the registration of the European Union trad ...
. In July 2019, it was reported that Huawei had also registered trademarks surrounding the word "Harmony" for desktop and mobile operating system software, indicating either a different name or a component of the OS.
Release
On 9 August 2019, Huawei officially unveiled HarmonyOS at its inaugural developers' conference in
Dongguan
Dongguan (; ) is a prefecture-level city in central Guangdong Province, China. An important industrial city in the Pearl River Delta, Dongguan borders the provincial capital of Guangzhou to the north, Huizhou to the northeast, Shenzhen to the ...
. Huawei described HarmonyOS as a
free,
microkernel
In computer science, a microkernel (often abbreviated as μ-kernel) is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system (OS). These mechanisms include low-level address space management, ...
-based distributed operating system for various types of hardware. The company focused primarily on IoT devices, including smart TVs,
wearable devices, and
in-car entertainment systems, and did not explicitly position HarmonyOS as a mobile OS.
HarmonyOS 2.0 launched at the Huawei Developer Conference on 10 September 2020. Huawei announced it intended to ship the operating system on its smartphones in 2021. The first developer beta of HarmonyOS 2.0 was launched on 16 December 2020. Huawei also released the
DevEco Studio IDE, which is based on
IntelliJ IDEA
IntelliJ IDEA is an integrated development environment (IDE) written in Java for developing computer software written in Java, Kotlin, Groovy, and other JVM-based languages. It is developed by JetBrains (formerly known as IntelliJ) and is av ...
, and a cloud emulator for developers in early access.
Huawei officially released HarmonyOS 2.0 and launched new devices shipping with the OS in June 2021, and started rolling out system upgrades to Huawei's older phones for users gradually.
On July 27, 2022, Huawei launched HarmonyOS 3 providing an improved experience across multiple devices such as smartphones, tablets, printers, cars and TVs. It also launched Petal Chuxing, a ride-hailing app running on the new version of the operating system.
Features
User interface
The HarmonyOS interface is based largely on the Android-based
EMUI
EMUI (formerly known as Emotion UI, and also known as Magic UI on Honor smartphones since 2019) is an Android-derived mobile operating system developed by Chinese technology company Huawei. It is used on the company's smartphones and tablets.
...
, but contains additional features. In addition to standard folders that require tapping on them to display their contents, folders can be enlarged to always show their contents without text labels directly on the home screen.
Apps can support "snippets", which expose a portion of the app's functionality (such as a media player's controls, or a weather forecast) via a pop-up window by swiping up on their icon, and can be pinned to the home screen as a
widget. Apps with snippets are denoted by an underline below their icon. Apps and services can provide ''cards''; as of HarmonyOS 3.0, cards can also be displayed as widgets with different sizes and shapes to adapt to the home screen layout, and can also be stacked.
The user interface font of HarmonyOS is HarmonyOS Sans. It is designed to be easy to read, unique, and universal. The system font is used throughout the operating system alongside its Android-based EMUI 12 counterpart, including third-party HarmonyOS and Android apps.
Software
Huawei AppGallery serves as the
application store for HarmonyOS, and can also distribute Android-compatible; HarmonyOS-native apps are marked with its logo on the corner of icons.
Both HarmonyOS apps and Android apps are allowed to utilize
Huawei Mobile Services Huawei Mobile Services (HMS) is a collection of proprietary services and application programming interfaces (APIs) developed by Huawei Technologies Co., Ltd. It is typically installed on Huawei devices running the Android operating system includin ...
as an option. However, HarmonyOS-native apps have access to capabilities such as distributed communications and cards.
Quick apps and Atomic Services
''Quick apps'' are
single-page apps written using
JavaScript
JavaScript (), often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. As of 2022, 98% of websites use JavaScript on the client side for webpage behavior, of ...
and
CSS, which can be added to the home screen. They are based on the industry standards formulated by the Quick App Alliance, comprising mainstream mobile phone manufacturers in China.
''Atomic Services'' can provide dynamic content and functionality, but do not provide an app proper; services are accessed via the "Service Center" interface, and are represented as cards that can be added to a favourites list or pinned to the home screen (with their accompanying code downloaded in the background). Services can also be used across multiple device classes.
Super Device
HarmonyOS supports cross-platform interactions between supported devices via the "Super Device" interface; devices are paired via a "radar" screen by dragging icons to the centre of the screen. Examples of Super Device features include allowing users to play back media saved inside a smartphone through a paired PC,
smart TV
A smart TV, also known as a connected TV (CTV), is a traditional television set with integrated Internet and interactive Web 2.0 features, which allows users to stream music and videos, browse the internet, and view photos. Smart TVs are a techn ...
or
speakers
Speaker may refer to:
Society and politics
* Speaker (politics), the presiding officer in a legislative assembly
* Public speaker, one who gives a speech or lecture
* A person producing speech: the producer of a given utterance, especially:
** I ...
; share PC screen recordings back to a smartphone; run multiple phone apps in a PC window; share files between a paired smartphone and PC; share application states between the paired devices, etc.
Hardware
HarmonyOS platform was not designed for a single device at the beginning but developed as a distributed operating system for various devices with memory sizes ranging from 128KB to over 4GB. Hence, the hardware requirements are flexible for the operating system and it may only need 128KB of memory for a variety of smart terminal devices.
Devices
![Huawei P30 camera](https://upload.wikimedia.org/wikipedia/commons/3/36/Huawei_P30_camera.jpg)
Huawei stated that HarmonyOS would initially be used on devices targeting the Chinese market. The company's former subsidiary brand,
Honor
Honour (British English) or honor (American English; see spelling differences) is the idea of a bond between an individual and a society as a quality of a person that is both of social teaching and of personal ethos, that manifests itself as a ...
, unveiled the Honor Vision line of smart TVs as the first consumer electronics devices to run HarmonyOS.
The HarmonyOS 2.0 beta launched on 16 December 2020 supports the
P30 series,
P40 series,
Mate 30 series,
Mate 40 series,
P50 series and MatePad Pro. HarmonyOS 2.0 was released for smartphones and tablets as updates for the P40 and
Mate X2 in June 2021. New
Huawei Watch,
MatePad Pro and PixLab X1 desktop printer models shipping with HarmonyOS were also unveiled.
As of October, 2021, HarmonyOS 2.0 has over 150 million users.
Development
The primary
IDE known as DevEco Studio for developing HarmonyOS apps was released by Huawei on September 9, 2020, based on IntelliJ IDEA and Huawei's SmartAssist. The IDE includes DevEco Device Tool, an integrated development tool for customizing HarmonyOS components, coding, compiling and visual debugging, similar to other third party IDEs such as
Visual Studio Code
Visual Studio Code, also commonly referred to as VS Code, is a source-code editor made by Microsoft with the Electron Framework, for Windows, Linux and macOS. Features include support for debugging, syntax highlighting, intelligent code comple ...
for
Windows
Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ser ...
,
Linux
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, w ...
and
macOS
macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lapt ...
.
Applications for HarmonyOS are mostly built using components of ArkUI, a Declarative User Interface framework. ArkUI elements are adaptable to various devices and include new interface rules with automatic updates along with HarmonyOS updates.
HarmonyOS primarily uses "App Pack" (.app) files for the distribution of software. Each App Pack contains a manifest file and one or more "HarmonyOS Ability Packages" (HAP, .hap), which are either an "entry" package (the main module of an app, of which there can be multiple instances for different device classes) or a feature module. Each HAP contains code for the module's ''abilities'', resources, libraries, and a
JSON file with configuration information. App Packs are published to AppGallery for distribution. The operating system contains libraries from the Linux kernel and
Android Open Source Project
Android is a mobile operating system based on a modified version of the Linux kernel and other open-source software, designed primarily for touchscreen mobile devices such as smartphones and tablets. Android is developed by a consortium of ...
(AOSP) to provide a compatibility environment for Android apps on supported platforms,
thus Android
APK files and
App Bundles (AAB) may also be published to AppGallery.
HarmonyOS as a universal single IoT platform allows developers to write apps once and run everywhere across devices such as phones, tablets, personal computers, TVs, cars, smartwatches, single board computers under
OpenHarmony, and screen-less IoT devices such as smart speakers.
As of June 2021, there were reportedly around 500,000 developers participated in developing HarmonyOS apps.
HarmonyOS ecosystem
HarmonyOS Connect
On May 18, 2021, Huawei revealed a plan to upgrade its HarmonyOS Connect brand with a standard badge during a summit in Shanghai to help industrial partners in producing, selling and operating products with third-party OEMs.
Allowing for fast and low-cost connections to users, smart devices like speakers, fridges and cookers of different brands powered by HarmonyOS can be connected and merged into a super device with a single touch of smartphone without the need to install apps.
The HarmonyOS Connect sets the platform apart from traditional mobile and computing platforms and the company's previous ecosystem attempts with its Android based EMUI and
LiteOS
Huawei LiteOS was a lightweight real-time operating system (RTOS) developed by Huawei. It is an open source, POSIX compliant operating system for Internet of things (IoT) devices, released under a three-clause BSD license. Microcontrollers of di ...
connectivity in the past.
HarmonyOS Cockpit
On April 27, 2021, Huawei launched a smart cockpit solution powered by HarmonyOS for electric and autonomous cars powered by its Kirin line of a
system-on-chip
A system on a chip or system-on-chip (SoC ; pl. ''SoCs'' ) is an integrated circuit that integrates most or all components of a computer or other electronic system. These components almost always include a central processing unit (CPU), memor ...
(SoC) solution. Huawei opened up APIs to help automobile OEMs, suppliers and ecosystem partners in developing features to meet user requirements.
Huawei designed a modular SoC for cars that will be pluggable and easy to upgrade to maintain the peak performance of the cockpit. Users would be able to upgrade the chipset as one can upgrade on an assembled desktop computer with its scalable distributed OS.
On December 21, 2021, Huawei launched a new smart console brand, HarmonySpace, a specialized HarmonyOS vehicle operating system. Based on Huawei's 1+8 ecology, apps on smartphones and tablets can be connected to the car seamlessly with HarmonySpace, which also provides smartphone projection capability.
On December 23, 2021, Huawei announced a new smart select car product – AITO M5, a medium-size
SUV
A sport utility vehicle (SUV) is a car classification that combines elements of road-going passenger cars with features from off-road vehicles, such as raised ground clearance and four-wheel drive.
There is no commonly agreed-upon definiti ...
with HarmonyOS ecosystem through continuous AI learning optimization and over-the-air upgrades. On July 4, 2022, Huawei officially launched AITO smart select car product to be shipped to customers sometime in August 2022. During the launch, the company received 10,000 pre-orders in 2 hours for its M7 model.
MineHarmony OS
On September 14, 2021, Huawei announced the launch of MineHarmony OS, a customized operating system by Huawei based on its in-house HarmonyOS for industrial use. MineHarmony is compatible with about 400 types of underground coal mining equipment, providing the equipment with a single interface to transmit and collect data for analysis. Wang Chenglu, President of Huawei’s consumer business AI and smart full-scenario business department, indicated that the launch of MineHarmony OS signified that the HarmonyOS ecology had taken a step further from
B2C to
B2B.
Relationship with OpenEuler
In terms of architecture, HarmonyOS has close relationship with OpenEuler, a community edition of
EulerOS
EulerOS is a commercial Linux distribution developed by Huawei for enterprise applications. It was first released on September 24, 2021.
Huawei has released a community edition of EulerOS, OpenEuler, along with the source code on Gitee.
KunLun ...
developed by Huawei, as they have inherited the sharing of kernel technology. The sharing is reportedly to be strengthened in the future in the areas of the distributed
software bus
A software bus is a software architecture model where a shared communication channel facilitates connections and communication between software modules. This makes software buses conceptually similar to the bus term used in computer hardware for i ...
, system security, device driver framework and new programming language.
Relationship with OpenHarmony, Linux and LiteOS
OpenHarmony is an open-source version of HarmonyOS donated by Huawei to the
OpenAtom Foundation. It supports devices running a mini system such as printers, speakers, smartwatches and any other smart device with memory as small as 128 KB, or running a standard system with memory greater than 128 MB. The open-source operating system contains the basic capabilities of HarmonyOS and does not depend on the
Android Open Source Project
Android is a mobile operating system based on a modified version of the Linux kernel and other open-source software, designed primarily for touchscreen mobile devices such as smartphones and tablets. Android is developed by a consortium of ...
(AOSP).
Conversely, HarmonyOS runs on Huawei's proprietary microkernel architecture and has used bits of
AOSP codes from EMUI with the
Linux kernel subsystem in smartphones to enable the operating system to run
APK apps with the widgets for compatibility without
root
In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the su ...
support just as with older Huawei EMUI-based smartphones. In addition, the OS supports native HarmonyOS apps on devices with
Huawei Mobile Services Huawei Mobile Services (HMS) is a collection of proprietary services and application programming interfaces (APIs) developed by Huawei Technologies Co., Ltd. It is typically installed on Huawei devices running the Android operating system includin ...
via Ark Compiler.
Using a multi-kernel design, HarmonyOS selects appropriate OS kernels for devices with various resource limitations. It uses the
LiteOS
Huawei LiteOS was a lightweight real-time operating system (RTOS) developed by Huawei. It is an open source, POSIX compliant operating system for Internet of things (IoT) devices, released under a three-clause BSD license. Microcontrollers of di ...
kernel instead of the Linux kernel on low-powered devices such as smartwatches and IoT devices.
Reception
Criticism
Speculations of Huawei's developer tools by ''
Ars Technica'', HarmonyOS running on smartphones was rumored as a "rebranded version of Android and EMUI" with nearly "identical code bases". Following the release of the HarmonyOS 2.0 beta, ''Ars Technica'' and
XDA Developers
XDA Developers (also known simply as XDA; often stylized as xda-developers) is a mobile software development community launched on 20 December 2002. Although discussion primarily revolves around Android, members also talk about many other opera ...
speculated that "the smartphone version of the OS had been
forked from
Android 10". ''Ars'' ''Technica'' alleged that it resembled the existing EMUI software used on Huawei devices, but with all references to "Android" replaced by "HarmonyOS". It was also noted that the
DevEco Studio software built based on
JetBrains
JetBrains s.r.o. (formerly IntelliJ Software s.r.o.) is a Czech software development company which makes tools for software developers and project managers. , the company has offices in Prague; Munich; Berlin; Boston, Massachusetts; Ams ...
open source
IntelliJ IDEA
IntelliJ IDEA is an integrated development environment (IDE) written in Java for developing computer software written in Java, Kotlin, Groovy, and other JVM-based languages. It is developed by JetBrains (formerly known as IntelliJ) and is av ...
IDE "shared components and tool chains" with
Android Studio
Android Studio is the official integrated development environment (IDE) for Google's Android operating system, built on JetBrains' IntelliJ IDEA software and designed specifically for Android development. It is available for download on Windows ...
.
When testing the new MatePad Pro in June 2021, ''Android Authority'' and ''
The Verge
''The Verge'' is an American technology news website operated by Vox Media, publishing news, feature stories, guidebooks, product reviews, consumer electronics news, and podcasts.
The website launched on November 1, 2011, and uses Vox Media ...
'' similarly observed similarities in "behavior", including that it was possible to install apps from Android
APK files on the HarmonyOS-based tablet, and that it included the Android 10
easter egg
Easter eggs, also called Paschal eggs, are eggs that are decorated for the Christian feast of Easter, which celebrates the resurrection of Jesus. As such, Easter eggs are common during the season of Eastertide (Easter season). The oldest tr ...
app reaffirming earlier rumor mills.
Initially, Huawei stated that HarmonyOS was a microkernel-based, distributed OS that was completely different from Android and iOS. A Huawei spokesperson subsequently stated that HarmonyOS supports multiple kernels and uses a Linux kernel if a device has a large amount of RAM, and that the company had taken advantage of a large number of third-party open-source resources, including Linux, to accelerate the development of a comprehensive architecture.
Market share
On December 23, 2021, Richard Yu, CEO of Huawei Consumer Business Group claimed that HarmonyOS had reached 300 million smartphones and other
smart devices
A smart device is an electronic device, generally connected to other devices or networks via different wireless protocols (such as Bluetooth, Zigbee, near-field communication, Wi-Fi, LiFi, or 5G) that can operate to some extent interactively and ...
, including 200 million devices in the ecosystem and 100 million third-party consumer products from industry partners.
Market research conducted in China by Strategy Analytics showed that Harmony OS was the third largest smartphone platform after
Apple iOS
iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple Inc. exclusively for its hardware. It is the operating system that powers many of the company's mobile devices, including the iPhone; the term also includes ...
and
Google Android
Android is a mobile operating system based on a modified version of the Linux kernel and other open-source software, open-source software, designed primarily for touchscreen mobile devices such as smartphones and tablet computer, tablets. Androi ...
, reaching a record high of 4% market share in China during the first quarter of 2022, up from zero just a year earlier. This increase in market share took place after the operating system was also launched for smartphone devices in June 2021. HarmonyOS was reported to be the fastest growing smartphone operating-system in China, which was the world's largest smartphone market in 2022. The research claimed that in the first quarter of 2022 the platform outgrew its rivals, such as Android and Apple iOS, from a low install base of about 150 million smart devices overall, particularly due to the good support in China and the HarmonyOS software upgrades that Huawei made available for its older handset models and its former sub-brands such as
Honor
Honour (British English) or honor (American English; see spelling differences) is the idea of a bond between an individual and a society as a quality of a person that is both of social teaching and of personal ethos, that manifests itself as a ...
.
On August 8, 2022, after the soft launch of HarmonyOS 3, Sina Finance, part of
Sina Corporation
Sina Corporation (, "new wave") is a Chinese technology company. Sina operates four major business lines: Sina Weibo, Sina Mobile, Sina Online, and Sinanet. Sina has over 100 million registered users worldwide. Sina was recognized by '' Southe ...
, and Huawei Central reported that the number of Huawei HarmonyOS Connect devices had exceeded 470 million units. By summer 2022, 14 OpenHarmony distributions had been launched.
Legal issues
In May 2019, Huawei applied for registration of the trademark "Hongmeng" through the Chinese Patent Office
CNIPA
The China National Intellectual Property Administration (CNIPA; ), also known as the Chinese Patent Office, is the patent office of the People's Republic of China (PRC). It was founded in 1980 as the Patent Office of the People's Republic of Ch ...
, but the application was rejected in pursuance to Article 30 of the
PRC
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
Trade Mark Law, citing the trademark was similar to that of "CRM Hongmeng" in graphic design and "Hongmeng" in Chinese word.
In less than a week before launching HarmonyOS 2.0 and new devices by Huawei, the
Beijing Intellectual Property Court announced the first-instance judgement in May 2021 to uphold the decision by CNIPA as the trademark was not sufficiently distinctive in terms of its designated services.
However, it was reported that the trademark had officially been transferred from Huizhou Qibei Technology to Huawei by end of May 2021.
See also
*
OpenHarmony
*
EulerOS
EulerOS is a commercial Linux distribution developed by Huawei for enterprise applications. It was first released on September 24, 2021.
Huawei has released a community edition of EulerOS, OpenEuler, along with the source code on Gitee.
KunLun ...
*
Flyme OS
Meizu Technology Co., Ltd. () is a Chinese consumer electronics manufacturer based in Zhuhai, Guangdong. Founded in 2003 by Jack Wong, Meizu began as a manufacturer of MP3 players and later MP4 players. In 2008, Meizu moved its focus to smar ...
*
DevEco Studio
References
External links
*
{{Distributed operating systems
2019 software
Embedded operating systems
Huawei products
Internet of things
Mobile Linux
Mobile operating systems
Tablet operating systems