Here we specify the general way the Android kernel assigns ids.
(Incomplete list, please fill as your discover new ones)
0 - root
1000 - system
1001 - radio
1002 - bluetooth
1003 - graphics
1004 - input
1005 - audio
1006 - camera
1007 - log
1008 - compass
1009 - mount
1010 - wifi
1011 - adb
1012 - install
1013 - media
1014 - dhcp
10000 - app_0
10001 - app_1
10002 - app_2
10003 - app_3
10004 - app_4
The maximum number of pids a linux OS can support is configurable.
This number can be found in the kernel's file /proc/sys/kernel/pid_max.
Our custom VM supports 32768 pids.