How many UIDs are possible in Android?

Question

I know that there are a number of system user IDs and a number of UIDs that corresponds to user applications. So I have the following questions:

1. How many system UIDs are there on Android? And what is the range of these UIDs?
2. What is the maximum number of applications UIDs are there? What is the range (I know that all application UIDs start from 10000)

Answer 1

According to system/core/include/private/android_filesystem_config.h, 0 is for root (obviously), UIDs 1000-9999 (from AID_SYSTEM to AID_NOBODY) are reserved by the system. And as the documentation says, the range of UIDs, reserved for user applications is 10000-99999 (from FIRST_APPLICATION_UID to LAST_APPLICATION_UID).

Upd: Since Android 4.1.1 the range of UIDs, reserved for user applications is 10000-19999.