Difference between revisions of "Android Booting"
(add to category:android) |
(add information about system initialization) |
||
| Line 1: | Line 1: | ||
| + | The bootup of an Android system consists of several phases, which are outlined here. | ||
| + | |||
== Device-specific startup == | == Device-specific startup == | ||
* firmware/bootloader | * firmware/bootloader | ||
| + | ** On the ADP1, there are multiple versions of the bootloader | ||
| + | |||
* kernel | * kernel | ||
* mount root file system | * mount root file system | ||
| Line 7: | Line 11: | ||
* run /init | * run /init | ||
** process /init.rc | ** process /init.rc | ||
| + | |||
| + | See the [[http://android.git.kernel.org/?p=platform/system/core.git;a=blob;f=init/readme.txt;hb=HEAD Android init language reference]] | ||
| + | |||
| + | == Sequence of boot steps on ADP1 == | ||
| + | === firmware === | ||
| + | * first-stage bootloader runs | ||
| + | ** it detects if a special key is held, and can launch the recovery image, or the 'fastboot' bootloader | ||
| + | === kernel === | ||
| + | * kernel is loaded | ||
| + | * kernel boots | ||
| + | ** core kernel initialization | ||
| + | ** driver initialization | ||
| + | === user space === | ||
| + | * user space starts | ||
| + | ** kernel runs /init | ||
| + | *** /init processes /init.rc and /init.rc.<machine_name> | ||
| + | *** activity manager is run | ||
| + | *** dalvik VM is started (zygote) | ||
| + | * activity manager starts core applications | ||
| + | ** com.android.phone - phone application | ||
| + | ** android.process.acore - home (desktop) and a few core apps. | ||
| + | * other processes started by /init: | ||
| + | ** adb | ||
| + | ** mediaserver | ||
| + | ** dbus-daemon | ||
| + | ** akmd | ||
| + | |||
| + | == Tools for analyzing Android Bootup == | ||
| + | * Bootchart - see [[Using Bootchart on Android]] | ||
== Notes on the Android startup procedure == | == Notes on the Android startup procedure == | ||
| Line 17: | Line 50: | ||
=== Interaction of different processes on application initialization === | === Interaction of different processes on application initialization === | ||
Talking about Android Process - http://blog.csdn.net/mawl2002/archive/2009/06/24/4295905.aspx | Talking about Android Process - http://blog.csdn.net/mawl2002/archive/2009/06/24/4295905.aspx | ||
| + | |||
[[Category:Android]] | [[Category:Android]] | ||
Revision as of 14:19, 12 January 2010
The bootup of an Android system consists of several phases, which are outlined here.
Contents
Device-specific startup
- firmware/bootloader
- On the ADP1, there are multiple versions of the bootloader
- kernel
- mount root file system
Generic startup
- run /init
- process /init.rc
See the [Android init language reference]
Sequence of boot steps on ADP1
firmware
- first-stage bootloader runs
- it detects if a special key is held, and can launch the recovery image, or the 'fastboot' bootloader
kernel
- kernel is loaded
- kernel boots
- core kernel initialization
- driver initialization
user space
- user space starts
- kernel runs /init
- /init processes /init.rc and /init.rc.<machine_name>
- activity manager is run
- dalvik VM is started (zygote)
- kernel runs /init
- activity manager starts core applications
- com.android.phone - phone application
- android.process.acore - home (desktop) and a few core apps.
- other processes started by /init:
- adb
- mediaserver
- dbus-daemon
- akmd
Tools for analyzing Android Bootup
- Bootchart - see Using Bootchart on Android
Notes on the Android startup procedure
Overview
See "Android Initialization Process" at: http://blog.chinaunix.net/u2/85805/showart_1421736.html
strace
http://benno.id.au/blog/2007/11/18/android-runtime-strace
Interaction of different processes on application initialization
Talking about Android Process - http://blog.csdn.net/mawl2002/archive/2009/06/24/4295905.aspx
