A/B update is Google’s built-in system update function in the Android system. This function mainly divides the partition into two so that the system can be switched when the system is updated.
The design purpose of this function is to reduce the failure rate caused by the system update, for example, many problems such as the inability to start and the cyclic restart during the update of many devices before.
The seamless A/B update is equivalent to not operating the old version when upgrading the system. If the new version fails, switch to the old version to ensure the user’s normal use.
This feature has been developed for many years, but the manufacturer chooses whether to use it and now Google is preparing to force the manufacturer to use it in the Android 11 version.
The key point of the Android update principle is to divide the system partition into two parts. Both partitions are loaded with the operating system, and only one of the partitions needs to be operated when performing the upgrade.
Before system upgrade: The operating system used by the user is located in partition A. At this time, system partition A and system partition B are the same version, and both systems can also be used.
After system upgrade: The operating system used by the user is located in partition A. At this time, system partition B has been upgraded to a new version, but system partition A is still the old version.
After the system restarts: After the system completes the upgrade and performs an automatic restart, the system used by the user is located in partition B, and system partition A is now in an idle state.
If the upgrade is wrong: If there is an error in the upgrade system, the rollback strategy is executed to return to the previous partition, so that the system upgrade will not affect the user’s use.
In most cases, software upgrades will not cause hardware failures, so if such errors occur, users can recover if they find a way to solve them.
But for users who don’t understand, if they can’t boot or restart cyclically, they can only contact the after-sales department of the manufacturer or even need to send the machine for maintenance.
When the seamless update is enabled, such problems caused by the system update can be significantly reduced, so in some ways, the after-sales pressure of the manufacturer can also be reduced.
XDA developer forum said that Google will force manufacturers to implement this policy in Android 11, which will be good news for users.