Many people confuse the relationship between Hongmeng and Linux.
Let me give you an example. The familiar Windows contains a kernel, a UI system, and a desktop program, so ordinary people can use Windows directly.
However, Linux is only a kernel (it provides concepts such as process management, file system, etc.), various APPs must be installed on Linux, and ordinary people can use it. Complete systems based on the Linux kernel include Ubuntu, debian, etc., and ordinary people can directly use these complete systems.
Therefore, Hongmeng targets complete systems such as Windows, Android and IOS, and Linux is only one of the kernels supported by Hongmeng. Hongmeng supports multiple kernels, including Linux and Liteos-a.
Hongmeng’s system is very large. See the picture below, the kernel is just one of them:
What is Liteos-a
Liteos-a is a kernel (also often referred to as an operating system, anyway, everyone mixes the operating system and the kernel). Common kernels are freeFTOS, rt-thread, UCOS, these are real-time operating systems (RTOS), Linux is not a real-time operating system.
With so many operating systems, why develop Liteos-a?
Most RTOS runs on MCU (microcontroller), does not support MMU (memory management unit), kernel space and APP space cannot be separated, the whole system will crash after APP error; POSIX interface is not supported, which makes a lot of The open source software cannot be run directly on the MCU.
The power of Linux is that it supports a lot of hardware, but it is too large, slow to start, and power-consuming. These shortcomings make it not suitable for use in the Internet of Things. For example, in a reversing camera, no one can bear to see the image after 2 seconds: even if you can bear it, it is difficult to optimize Linux to boot within 2 seconds.
Liteos-a was born for the Internet of Things, supports MMU, supports kernel/APP space isolation, supports space isolation of each APP, and makes the system more robust; supports POSIX interface, a large number of open source software can be used directly on Liteos-a; fast startup and power saving .
Liteos-a is a lightweight core with exquisite design. For it to succeed, it must hold more chips and more peripherals. This is why we transplanted Liteos-a to non-Hisilicon chips and recorded tutorials.
In addition to Liteos-a, there is also Liteos-m, which runs on chips without MMU, that is, runs on MCU...
If you want to know more, please click https://harmonyos.51cto.com/posts/ids/?id=841 to download the manual (PDF version) at the end of the article