OpenAtom OpenHarmony, or abbreviated as OpenHarmony (OHOS), is a family of open-source operating systems based on HarmonyOS derived from LiteOS, donated the L0-L2 branch source code by Huawei to the OpenAtom Foundation. Similar to HarmonyOS, the open-source distributed operating system is designed with a layered architecture, which consists of four layers from the bottom to the top, i.e., the kernel layer, system service layer, framework layer, and application layer.[4]
OpenHarmony supports various 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.[5]
The system contains the basic and some advanced capabilities of HarmonyOS.[6]
History
The first version of OpenHarmony was launched by the OpenAtom Foundation on September 10, 2020, after receiving a donation of the open-source code from Huawei.[7]
The OpenHarmony 2.0 (Canary version) was launched in June 2021, supporting a variety of smart terminal devices.[7]
Based on its earlier version, OpenAtom Foundation launched OpenHarmony 3.0 on September 30, 2021, and brought substantial improvements over the past version to optimize the operating system.[8]
A release of OpenHarmony supporting devices with up to 4 GB RAM was made available in April 2021.[9]
OpenAtom Foundation added a UniProton kernel, a hardware-based real-time operating system, into its repo as part of the Kernel subsystem of the OpenHarmony operating system on August 10, 2022.[10]
Development
The primary IDE known as DevEco Studio to build OpenHarmony applications.
Applications for OpenHarmony are mostly built using components of ArkUI, a Declarative User Interface framework. ArkUI elements are adaptable to various custom open-source hardware and industry hardware devices and include new interface rules with automatic updates along with HarmonyOS updates.[11]
Like HarmonyOS, OpenHarmony uses App Pack files suffixed with .app, also known as APP files on AppGallery and third party distribution application stores on OpenHarmony-based and non-OpenHarmony operating systems such as Linux-based Unity Operating System which is beneficial for interoperability and compatibility. Each App Pack has one or more HarmonyOS Ability Packages (HAP) containing code for their abilities, resources, libraries, and a JSON file with configuration information.[12]
While incorporating the OpenHarmony layer for running the APP files developed based on HarmonyOS APIs, the operating system utilizes the main Linux kernel for bigger memory devices, as well as the RTOS-based LiteOS kernel for smaller memory-constrained devices, as well as add-ons, custom kernels in distros in the Kernel Abstract Layer (KAL) subsystem that is not kernel dependent nor instruction set dependent. For webview applications, it incorporates Chromium Embedded Framework software framework at system level for security with its custom OpenHarmony nweb software engine that support some Chromium technologies.[13]
Unlike with open-source Android operating system with countless third-party dependency packages repeatedly built into the apps at a disadvantage when it comes to fragmentation. The OpenHarmony central warehouse with the Special Interest Group at OpenAtom governance provides commonly used third-party public warehouses for developers in the open-source environment which brings greater interoperability and compatibility with OpenHarmony-based operating systems. Apps does not require repeated built-in third-party dependencies, such as Chromium, Unity and Unreal Engine. This can greatly reduce the system ROM volume.[14]
Harmony Distributed File System (HMDFS) is a distributed file system designed for large-scale data storage and processing that is also used in openEuler. It is inspired by the Hadoop Distributed File System (HDFS). The file system suitable for scenarios where large-scale data storage and processing are essential, such as IoT applications, edge computing, and cloud services.[15] On Orange Pi OS (OHOS), the native file system shows LOCAL and shared_disk via OpenHarmony's Distributed File System (HMDFS)
File path/root folder for the file system uses ">" instead of traditional "\" in Unix/Linux/Unix-like and "/" on Windows with its DLL (Dynamic-link library) system.
Access token manager is an essential component in OpenHarmony-based operating systems, responsible for unified app permission management based on access tokens. Access tokens serve as identifiers for apps, containing information such as app ID, user ID, app privilege level (APL), and app permissions. By default, apps can access limited system resources. ATM ensures controlled access to sensitive functionalities.[16]
OpenHarmony kernel abstract layer employs the musl libc library and native APIs, providing support for the Portable Operating System Interface (POSIX) for Linux syscalls within the Linux kernel side and LiteOS kernel that is the inherent part of the original LiteOS design in POSIX API compatibility.[17] Developers and vendors can create components and applications that work on the kernel based on POSIX standards.[18]
Also, vendors built operating systems on top of OpenHarmony itself as well as OpenHarmony-based Oniro OS can build and integrate their new or existing custom kernels to their open and commercial distributions of software stack outside the two default kernels of the Multikernel architecture such as Huawei's HarmonyOS NEXT iteration of HarmonyOS as addons on OpenHarmony whether individual distros supports multiple custom kernels or one custom kernel or one from the default kernels chosen, providing vendors flexibility in its architecture design in the kernel abstract layer architecture abstracting differences preserving system layer functions from apps, DSoftBus localised device transmission functionalities to drivers.[19]
Timeline
September 10, 2020 – Initial release of OpenHarmony with support for devices with 128 KB – 128 MB RAM
April 2021 – OpenHarmony release with support for smartphones and other devices with 128 MB – 4 GB RAM
October 2021 – OpenHarmony release with support for additional devices with 4+ GB RAM[20]
Hardware
OpenHarmony can be deployed on various hardware devices of ARM, RISC-V and x86 architectures with memory volumes ranging from as small as 128 KB up to more than 1 MB. It supports hardware devices with three types of system as follows:[21]
Mini system – running on such devices as connection modules, sensors, and wearables, with memory equal to or larger than 128 KB and equipped with processors including ARM Cortex-M and 32-bit RISC-V.
Small system – running on such devices as IP cameras, routers, event data recorders, with memory equal to or larger than 1 MB and equipped with processors including ARM Cortex-A.
Standard system – running on devices with enhanced interaction, 3D GPU, rich animations and diverse components, with memory equal to or larger than 128 MB and equipped with processors including ARM Cortex-A.
Compatibility certification
To ensure OpenHarmony-based devices are compatible and interoperable in the ecosystem, the OpenAtom Foundation has set up product compatibility specifications, with a Compatibility Working Group to evaluate and certify the products that are compatible with OpenHarmony.[22][23]
The following two types of certifications were published for the partners supporting the compatibility work, with the right to use the OpenHarmony Compatibility Logo on their certified products, packaging, and marketing materials.[24]
Development boards, modules, and software distributions
Equipment
On April 25, 2022, 44 products have obtained the compatibility certificates, and more than 80 software and hardware products are in the process of evaluation for OpenHarmony compatibility.[25]
Since OpenHarmony was open source in September 2020 to December 2021, more than 1,200 developers and 40 organizations have participated in the open source project and contributed code. At present, OpenHarmony has developed to 4.x version.
Software version History
Version number
Release date
API level
Main features
1.0
September 10, 2020
5
Support terminal devices with memory from 128KB to 128MB
1.1.0 long-term support version
April 1, 2021
5
Add and upgrade subsystems to unify the artificial intelligence engine framework
2.0 Canary version
June 1, 2021
6
Support smart terminal devices with more than 128MB of memory, and introduce the Linux kernel as the technical base
2.2 Beta version
September 4, 2021
6
Possess typical distributed capabilities and media product development capabilities
3.0 long-term support version
September 30, 2021
7
New features and functions for lightweight, small and standard systems
3.1 Beta version
December 31, 2021
8-9
Enhance basic capabilities, system distribution capabilities, system application framework capabilities, and lightweight system capabilities, etc.
Enhance the basic capabilities of lightweight and standard systems, the framework capabilities of standard system applications, and the application capabilities of standard systems
4.0 beta version 1
June 3, 2023
10
Improve the capabilities of the standard system and further improve the capabilities and effects of ArkUI components
4.0 release version
October 26, 2023
10
A large number of ArkTS APIs have been added, and the scope of distributed hardware support has been expanded
4.1 beta 1 version
December 31, 2023
11
New system capabilities by improving software architecture. Optimizations on ArkUI for component capabilities and effects. Enhancement on graphics window for dynamic effects and screen adaptation for different hardware. App framework improves extension capabilities, distributed soft bus connection, and more. Improvements to audio and camera frameworks on open-source code.[27]
Key Highlighted Features in beta 1:
Native device-side AI support for training interface and ArkTS interface for NNRt (Neural Network Runtime) backend configurations via MindSpore Lite AI framework.
New interfaces supporting custom cursor interaction, keystroke monitoring, and recognition of various gestures between touch, keyboard/mouse.
Support cleaning up redundant user credentials, vibration feedback for authentication failure, and dynamic fingerprint disabling function on various devices.
Various improvements in telephony such as SIM card text message management, roaming scenarios, and call interception framework.
Configuration support for pressing power button or closing the lid to sleep or turn off the screen.
Various features for power management, including wake-up reason retrieval and screen power status control.
Advanced animation capabilities such as support for hardware hollowing out, screen rounding, and navigation transition animation, especially with telephony devices and other various computing devices.
Installation, update, and also uninstallation of driver programs with menu configs and query capabilities in the system.
WebRTC capabilities improvement, CSS cursor style enhancement, and support for nested scrolling with Chromium version upgrades on CEF for OpenHarmony nweb software engine that takes advantage of Chromium web browser and Blink browser engine.[28]
4.1 release version
March 31, 2024
11
4,000 APIs have been added to provide developers with rich app development capabilities, the open capabilities of application development are presented in the Kit dimension, providing developers with clearer logic and scenario-based perspectives, openness and dynamic capabilities of ArkUI components have been further enhanced, the web capabilities have been continuously supplemented, making it easier for developers to quickly build applications using Web capabilities, and distributed capabilities have further enhanced stability of networking. Connection security, etc., media support for richer encoding, support for more refined broadcast control capabilities, etc.[29][30]
Software distributions
OpenHarmony is the most active open source project hosted on the Gitee platform. As of September 2023, it has over 30 open-source software distributions compatible with OpenHarmony for various sectors such as education, finance, smart home, transportation, digital government and other industries.[31][32][33]
Midea IoT OS
Midea, a Chinese electrical appliance manufacturer launched Midea IoT operating system 1.0. An IoT centric operating system based on OpenHarmony 2.0 officially launched in October 2021. After, the company used HarmonyOS operating system with Huawei partnership for its smart devices compatibility since June 2, 2021 launch of HarmonyOS 2.0.[34][35][36][37]
OpenHarmony in Space
On January 6, 2022, OpenHarmony in Space (OHIS) by OHIS Working Group and Dalian University of Technology led by Yu Xiaozhou was reported to be a vital play in the future from a scientific and engineering point of view, expecting to open up opportunities for development in China's satellite systems, and surpass SpaceX’s Star Chain plan with the idea of micro-nano satellite technology.[38]
SwanLinkOS
Based on OpenHarmony, SwanLinkOS was released in June 2022 by Honghu Wanlian (Jiangsu) Technology Development, a subsidiary of iSoftStone, for the transportation industry. The operating system supports mainstream chipsets, such as Rockchip RK3399 and RK3568, and can be applied in transportation and shipping equipment for monitoring road conditions, big data analysis, maritime search and rescue.[39]
It was awarded the OpenHarmony Ecological Product Compatibility Certificate by the OpenAtom Foundation.[40]
ZhihongmetaOS
On August 29, 2022, Hongyuan Zhitong Technology has recently released new software called ZhihongmetaOS, which stands on the surface of the OpenHarmony 3.1 build and has qualified the eligibility for the OpenHarmony 3.1 evaluation and gained the Ecological Product compatibility certificate. This OpenHarmony OS distribution works on higher security, strong business consistency, and improved performance for consumers targeted mainly for business or industrial users. It is reported that focused on OS optimization, component algorithms, industry consulting and planning, hardware design, and production. At the moment, ZhihongmetaOS V1.0 is only available in the public security sector in China. However, the company will soon extend the roots of the respective firmware to more industries. For instance, environmental protection, and water conservation.[41]
ArcherMind HongZOS
On November 7, 2022, ArcherMind Cooperation that deals with operating systems, interconnection solutions, smart innovations, and R&D aspects launched the HongZOS system that supports OpenHarmony and HiSilicon chips, solution mainly focuses on AIoT in industrial sectors.[42]
Orange Pi OS (OHOS)
On November 28, 2022, Orange Pi launched the Orange Pi OS based on the open-source OpenHarmony version.[43] In October 2023, they released the Orange Pi 3B board with the Orange Pi OHOS version for hobbyists and developers based on the OpenHarmony 4.0 Beta1 version.[44][45][46]
RobanTrust OS
On December 23, 2022, the integrated software and hardware solution together with the self-developed hardware products of Youbo Terminal runs RobanTrust OS, based on OpenHarmony that was launched as version 1.0 with 3.1.1 compatibility release.[47]
HiHopeOS
On January 12, 2023, Runhe Software launched HiHopeOS operating system based on OpenHarmony standard system. Runhe Software HH-SCDAYU800 development board powered by RISC-V for RISC-V based chips, supports Bluetooth, Wi-Fi, audio, video, and camera functions support multiple video input and output interfaces, and provides rich expansion interfaces. It is used for industrial control tablets, smart large screens, smart NVR, information release systems, cloud terminals, vehicle central control, and other scenarios, support medical imaging, video conferencing, home robots and drones, and other mid-to-high-end applications, and reportedly used in edge computing, artificial intelligence, image recognition, multimedia, and other fields of the high technology sector.[48]
USmartOS
On April 15, 2023, Tongxin Software became OpenAtom's OpenHarmony Ecological Partner.[49] An intelligent terminal operating system for enterprises in China by Tongxin Software was passed for compatibility certification on June 7, 2023. Tongxin intelligent terminal operating system supports ARM, X86, and other architectures that is supported. Tongxin has established cooperative relations with major domestic mobile chip manufacturers and has completed adaptations using the Linux kernel. Together with the desktop operating system and the server operating system, it constitutes the Tongxin operating system family.[50]
PolyOS Mobile
PolyOS Mobile is an AIIoT open-source operating system tailored for RISC-V intelligent terminal devices by the PolyOS Project based on OpenHarmony, which was released on August 30, 2023, and is available for QEMU virtualisation on Windows 10 and 11 desktop machines.[51]
LightBeeOS
LightBeeOS launched on September 28, 2023, is an OpenHarmony-based distro that supports financial level security, with distribution bus by Shenzhen Zhengtong Company used for industrial public banking solutions of systems, tested on ATM machines with UnionPay in Chinese domestic market. The operating system has been launched with OpenHarmony 3.2 support and up.[52]
KaihongOS
On January 14, 2023, Red Flag smart supercharger, first launched on OpenHarmony-based KaihongOS with OpenHarmony 3.1 support that supports the distributed soft bus that allows interconnection with other electronic devices and electrical facilities.[53]
On January 17, 2023, an electronic class card with 21.5-inch screen developed by Chinasoft and New Cape Electronics.[54]
On November 17, 2023, Kaihong Technology and Leju Robot collaborated to release the world's first humanoid robot powered by the open-source OpenHarmony distro KaihongOS with Rockchip SoC hardware using RTOS kernel technology for industrial robotic machines with predictable response times in determinism.[55]
Upstream and Downstream Software Releases
Oniro project, focus on horizontal platform. Embedded OS with Yocto, Linux, Zephyr, IP toolchain, maintenance, OTA, blueprints and OpenHarmony. Oniro OS 2.0 was released in 2022 and Oniro OS 3.0 based on OpenHarmony 3.2 LTS in October 2023, alongside latest 4.0 version as of December 6, 2023 on the main branch.[66][67][68]
Software version History
OpenHarmony version
Version number
Release date
API level
Main features
3.0 LTS
1.0
September 28, 2021
7
New features and functions for lightweight, small and standard systems
3.1
2.0
2022
8-9
Enhance basic capabilities, system distribution capabilities, system application framework capabilities, and lightweight system capabilities, etc.
3.2 LTS
3.0
October 2023
9
Enhance the basic capabilities of lightweight and standard systems, the framework capabilities of standard system applications, and the application capabilities of standard systems
4.0
4.0
December 6, 2023
10
A large number of ArkTS APIs have been added, and the scope of distributed hardware support has been expanded. React Native Ported.
Oniro OS
Family of open-source operating systems based on OpenHarmony
On September 28, 2021, the Eclipse Foundation and the OpenAtom Foundation announced their intention to form a partnership to collaborate on OpenHarmony European distro which is a global family of operating systems under it and a family of the OpenHarmony operating system.[59]
Oniro OS, also known as Eclipse Oniro Core Platform launched on October 26, 2021, as Oniro OS 1.0, which is implemented to be compatible with HarmonyOS based on OpenHarmony L0-L2 branch source code, was later launched by the Eclipse Foundation for the global market with the founding members including Huawei, Linaro and Seco among others joined later on. Oniro is designed on the basis of open source and aims to be transparent, vendor-neutral, and independent system in the era of IoT with globalisation and localisation strategies resolving a fragmentated IoT and Embedded devices market.[60][61]
The operating system features a Linux Yocto kernel allows the OS to run on larger embedded devices, such as Raspberry Pi-class devices and a RTOS-based Zephyr kernel alongside third add-on kernel, FreeRTOS and fourth LiteOS kernel. [62] and other custom add-on kernels by OEMs and ODMs that allows the OS to run on highly resource-constrained devices, such as a coffee maker or a thermostat. The goal is to increase the distro with partners that create their own OpenHarmony-Oniro compatible distros that increase interoperability which reduces fragmentation of diverse platforms with diverse set of hardwares with enhancements from derived project back to original project in Upstream development. It is also used for Downstream development by Huawei for commercial use on in-house custom HarmonyOS NEXT stack of HarmonyOS in global and western markets for compatibility and interoperability with connected IoT systems as well as custom third-party support on-device AI features alongside Huawei MindSpore solutions.[63][64][65]
Huawei officially announced the commercial proprietary HarmonyOS NEXT, microkernel-based core distributed operating system for HarmonyOS at Huawei Developer Conference 2023 (HDC) on August 4, 2023, which supports only native APP apps via Ark Compiler with Huawei Mobile Services (HMS) Core support. Based on modified OpenHarmony and Oniro OS. HarmonyOS NEXT has the HarmonyOS microkernel at its core and it has no apk compatibility support.[69]
In the long term, as the company builds up the software root in downstream development for both domestic Chinese and global markets, the closed HarmonyOS NEXT customised L0-L2 full branch source code of the OpenHarmony operating system is aimed to replace the current closed-source L3-L5 branch since OpenHarmony 2.2 fork branch with 8GB worth of code up to 4.x with 60% codebase designed with a dual-frame architecture that is compatible with Android with EMUI userland in the multikernel architecture of HarmonyOS from current Linux kernel on phones and tablets, cars, TVs and advanced wearables, alongside lightweight LiteOS kernel on basic wearables and various IoT smart devices. On the same day at HDC 2023, the developer preview version of HarmonyOS NEXT was opened for cooperating enterprise developers to build and test native mobile apps. It will be open to all developers in the first quarter of 2024 according to the official announcement.[70][71][72]
On 18 January 2024, Huawei announced HarmonyOS NEXT Galaxy stable rollout will begin in Q4 2024 based on OpenHarmony 5.0 (API 12) version after OpenHarmony 4.1 (API 11) based Q2 Developer Beta after release of public developer access of HarmonyOS NEXT Developer Preview 1 that has been in the hands of closed cooperative developers partners since August 2023 debut. The new system of HarmonyOS 5 version will replace current HarmonyOS system for commercial Huawei consumer devices that can only run native HarmonyOS apps built for HarmonyOS and OpenHarmony as well as localsation using Oniro OS for downstream development at global level.[73]
In terms of architecture, OpenHarmony alongside HarmonyOS has close relationship with server-based Multikernel operating system OpenEuler, which is a community edition of EulerOS, as they have implemented the sharing of kernel technology as revealed by Deng Taihua, President of Huawei's Computing Product Line.[74] The sharing is reportedly to be strengthened in the future in the areas of the distributed software bus, system security, device driver framework and new programming language.[75]
Harmony Distributed File System (HMDFS) is a distributed file system designed for large-scale data storage and processing that is also used in openEuler server operating system.
