Find Linux kernel version:
- Found on About phone: https://www.quora.com/What-does-kernel-version-mean-and-why-is-the-Android-version-and-the-kernel-version-different
- big list: http://android.stackexchange.com/questions/51651/which-android-runs-which-linux-kernel but it was wrong according to my about phone
Version usage data: https://en.wikipedia.org/wiki/Android_version_history#/media/File:Android_historical_version_distribution_-_vector.svg
- ARM
- x86
- MIPS. See also: http://www.androidauthority.com/nintendo-64-android-l-microcontrollers-story-mips-538596/
Each app runs as a different user.
This implies that each app runs on a different Dalvik VM: http://android.stackexchange.com/questions/42129/why-each-android-application-runs-on-a-different-dalvik-vm-process