The heat of Xiaomi depends in large part on MIUI Of success, MIUI Continuously updated every Friday so far one hundred and thirty-two Zhou, even if the players who do not use Xiaomi mobile phones MIUI The attention of, MIUI What kind of magic does it have? Today we will explore MIUI Past life and present life.
To understand the development of MIUI, it is essential to talk about Android, which has become increasingly popular in recent years. First, take a look at the system architecture of Android, which is divided into four layers, from high to low, including the application layer (Applications), the application framework layer (Application Framework), the system runtime layer (Libraries+Android RunTime), and the Linux core layer (Linux Kernel).
Since the original MIUI is in the form of ROM, which is adapted to multiple mobile phones, the number of models to be adapted is very critical. Most of the parts related to model adaptation in android are in the bottom red part of the Linux kernel, The core system services of Android depend on the Linux kernel, such as memory management, process management, power management, security, network protocol stack and driver model. In order to adapt the model as soon as possible, the early MIUI used the bottom layer of CM (after 4.0, MIUI has abandoned CM, which will be discussed in the next issue).
Why use the bottom layer of CM?
CM, with its full name CyanogenMod, is the largest and most professional Android rom customization community. Google's open source code only supports the Nexus series. CM has added support for many other models, with changes mainly in the kernel. These kernel source codes are jointly developed by manufacturers according to the GPL protocol, and CM will make some changes on them (such as adding radio, 720P video, etc.). The driver cores of different manufacturers and mobile phones are different, so Google has defined a universal interface HAL, so that the upper layer can command the lower layer. However, due to various considerations, manufacturers are generally unwilling to disclose their underlying details, so they have built a factory adaptation layer on top of the kernel and driver. In this way, without the permission of the adaptation layer, the upper layer code cannot command the kernel and driver even though it passes through HAL, which means that a considerable part of the hardware cannot be used. However, the adaptation layer of the manufacturer is often not disclosed, which makes it impossible to run on this model even if there is a ROM. Therefore, in the era of 2.2 and 2.3, except for a few models (such as Google Nexus One), MIUI adaptation for other models is completed through the open source achievements of CM and various developers. CM and developers acquire or analyze the underlying interface through various ways, and other ROMs can complete the adaptation of this model.
If there is no CM, will there be MIUI? If there is no CM, MIUI will continue to exist, but the supported machines are limited to the nexus series and HD2, which can be directly found in the open source community.
Using the bottom layer of CM reduces the burden of the MIUI team, and also enables the MIUI team to focus more on what they are good at, that is, what they see and feel directly in use: interface, buttons, system, phone, SMS, contacts, theme, music, library... This part has always been the focus of MIUI.
MIUI 2.3 The excellent user experience brought to users by the times is mainly reflected in UI Design and variable theme and lock screen interface, T9 One of the reasons why Xiaomi has always been touted as a fan's mobile phone is that the MIUI team has a thorough understanding of customization.
