Looking into the Android processes (via “ps” inside the “adb shell” environment):
radio 29 1 5420 468 ffffffff afe0d0ec S /system/bin/rild
root 30 1 82016 15536 c009a694 afe0cba4 S zygote
media 31 1 20948 1020 ffffffff afe0ca7c S /system/bin/mediaserver
root 32 1 784 240 c02094ac afe0c7dc S /system/bin/installd
keystore 33 1 1616 188 c01a65e8 afe0d40c S /system/bin/keystore
root 34 1 728 180 c003d444 afe0d6ac S /system/bin/sh
root 35 1 824 256 c00b7dd0 afe0d7fc S /system/bin/qemud
root 37 1 3380 188 ffffffff 0000eca4 S /sbin/adbd
root 44 34 780 224 c02094ac afe0c7dc S /system/bin/qemu-props
system 52 30 157544 28996 ffffffff afe0ca7c S system_server
app_24 95 30 104100 14668 ffffffff afe0da04 S com.example.android.softkeyboard
radio 98 30 122060 17124 ffffffff afe0da04 S com.android.phone
app_7 102 30 127904 22164 ffffffff afe0da04 S android.process.acore
We can see that system_server is started of by the zygote process. And looking into the system_server memory:
# cat maps
00008000-00009000 r-xp 00000000 1f:00 400 /system/bin/app_process
00009000-0000a000 rwxp 00001000 1f:00 400 /system/bin/app_process
0000a000-004d6000 rwxp 0000a000 00:00 0 [heap]
10000000-10001000 ---p 10000000 00:00 0
10001000-10100000 rwxp 10001000 00:00 0
40000000-40008000 r-xs 00000000 00:07 187 /dev/ashmem/system_properties (deleted)
40008000-40009000 r-xp 40008000 00:00 0
40009000-402aa000 rwxp 00000000 00:07 283 /dev/ashmem/mspace/dalvik-heap/zygote/0 (deleted)
402aa000-41009000 ---p 002a1000 00:07 283 /dev/ashmem/mspace/dalvik-heap/zygote/0 (deleted)
41009000-41038000 r-xs 00000000 1f:00 433 /system/fonts/DroidSans.ttf
41038000-4104c000 rwxp 41038000 00:00 0
4104c000-4104d000 ---p 00000000 00:07 285 /dev/ashmem/dalvik-LinearAlloc (deleted)
4104d000-41330000 rwxp 00001000 00:07 285 /dev/ashmem/dalvik-LinearAlloc (deleted)
41330000-4154c000 ---p 002e4000 00:07 285 /dev/ashmem/dalvik-LinearAlloc (deleted)
4154c000-416d0000 r-xs 00000000 1f:00 620 /system/framework/core.jar
416d0000-41a5d000 r-xs 00000000 1f:01 275 /data/dalvik-cache/system@framework@core.jar@classes.dex
41a5d000-41a91000 rwxp 41a5d000 00:00 0
41a91000-41af6000 r-xs 00000000 1f:00 629 /system/framework/ext.jar
41af6000-41bee000 r-xs 00000000 1f:01 276 /data/dalvik-cache/system@framework@ext.jar@classes.dex
41bee000-41e6c000 r-xs 00000000 1f:00 632 /system/framework/framework.jar
41e6c000-42456000 r-xs 00000000 1f:01 277 /data/dalvik-cache/system@framework@framework.jar@classes.dex
42456000-424d4000 rwxp 42456000 00:00 0
424d4000-424e7000 r-xs 00000000 1f:00 624 /system/framework/android.policy.jar
424e7000-42510000 r-xs 00000000 1f:01 278 /data/dalvik-cache/system@framework@android.policy.jar@classes.dex
42510000-4258b000 r-xs 00000000 1f:00 623 /system/framework/services.jar
4258b000-42697000 r-xs 00000000 1f:01 279 /data/dalvik-cache/system@framework@services.jar@classes.dex
42697000-426c1000 rwxp 42697000 00:00 0
426c1000-426cb000 r-xs 00000000 1f:00 291 /system/app/SettingsProvider.apk
426cb000-426cd000 r-xs 00008000 1f:00 291 /system/app/SettingsProvider.apk
426cd000-426d7000 r-xs 00000000 1f:00 291 /system/app/SettingsProvider.apk
426d7000-426e2000 r-xs 00000000 1f:01 386 /data/dalvik-cache/system@app@SettingsProvider.apk@classes.dex
426e2000-426ee000 rwxp 426e2000 00:00 0
426ee000-426fd000 rwxp 426ee000 00:00 0
426fd000-426fe000 rwxs 00000000 00:07 390 /dev/ashmem/SurfaceFlinger read-only heap (deleted)
426fe000-42704000 rwxp 426fe000 00:00 0
42705000-42711000 rwxp 42705000 00:00 0
42711000-42748000 rwxp 42711000 00:00 0
42748000-42749000 rwxs 00000000 00:07 565 /dev/ashmem/SurfaceFlinger Client control-block (deleted)
42749000-4274c000 rwxp 42749000 00:00 0
4274c000-4274d000 rwxs 00000000 00:07 619 /dev/ashmem/SurfaceFlinger Client control-block (deleted)
4274d000-4274f000 r-xs 00000000 1f:00 434 /system/fonts/Clockopia.ttf
4274f000-42750000 rwxs 00000000 00:07 836 /dev/ashmem/SurfaceFlinger Client control-block (deleted)
42752000-42754000 r-xs 00000000 1f:00 434 /system/fonts/Clockopia.ttf
42754000-42757000 rwxp 42754000 00:00 0
42757000-4275b000 rwxs 00000000 00:07 776 /dev/ashmem/gralloc-buffer (deleted)
4275e000-42776000 rwxs 00000000 00:07 1052 /dev/ashmem/gralloc-buffer (deleted)
42777000-4277b000 rwxs 00000000 00:07 764 /dev/ashmem/gralloc-buffer (deleted)
4277d000-4277f000 r-xs 00000000 1f:00 434 /system/fonts/Clockopia.ttf
And extracting all the ashmem:
40000000-40008000 r-xs 00000000 00:07 187 /dev/ashmem/system_properties (deleted)
40009000-402aa000 rwxp 00000000 00:07 283 /dev/ashmem/mspace/dalvik-heap/zygote/0 (deleted)
402aa000-41009000 ---p 002a1000 00:07 283 /dev/ashmem/mspace/dalvik-heap/zygote/0 (deleted)
4104c000-4104d000 ---p 00000000 00:07 285 /dev/ashmem/dalvik-LinearAlloc (deleted)
4104d000-41330000 rwxp 00001000 00:07 285 /dev/ashmem/dalvik-LinearAlloc (deleted)
41330000-4154c000 ---p 002e4000 00:07 285 /dev/ashmem/dalvik-LinearAlloc (deleted)
426fd000-426fe000 rwxs 00000000 00:07 390 /dev/ashmem/SurfaceFlinger read-only heap (deleted)
42748000-42749000 rwxs 00000000 00:07 565 /dev/ashmem/SurfaceFlinger Client control-block (deleted)
4274c000-4274d000 rwxs 00000000 00:07 619 /dev/ashmem/SurfaceFlinger Client control-block (deleted)
4274f000-42750000 rwxs 00000000 00:07 836 /dev/ashmem/SurfaceFlinger Client control-block (deleted)
42757000-4275b000 rwxs 00000000 00:07 776 /dev/ashmem/gralloc-buffer (deleted)
4275e000-42776000 rwxs 00000000 00:07 1052 /dev/ashmem/gralloc-buffer (deleted)
42777000-4277b000 rwxs 00000000 00:07 764 /dev/ashmem/gralloc-buffer (deleted)
42e1f000-42e60000 rwxp 00000000 00:07 379 /dev/ashmem/mspace/dalvik-heap/zygote/1 (deleted)
42e60000-43b7f000 ---p 00041000 00:07 379 /dev/ashmem/mspace/dalvik-heap/zygote/1 (deleted)
43b7f000-43de0000 rwxp 00000000 00:07 381 /dev/ashmem/mspace/dalvik-heap/2 (deleted)
43de0000-4489f000 ---p 00261000 00:07 381 /dev/ashmem/mspace/dalvik-heap/2 (deleted)
45436000-4544e000 rwxs 00000000 00:07 1061 /dev/ashmem/gralloc-buffer (deleted)
45478000-454ad000 rwxp 00000000 00:07 1155 /dev/ashmem/dalvik-heap-bitmap/mark/0 (deleted)
45823000-45859000 rwxp 00000000 00:07 1156 /dev/ashmem/dalvik-heap-bitmap/mark/1 (deleted)
45b74000-45c74000 rwxs 00000000 00:07 481 /dev/ashmem/CursorWindow (deleted)
46074000-46174000 rwxs 00000000 00:07 497 /dev/ashmem/CursorWindow (deleted)
464b0000-4653f000 rwxs 00000000 00:07 709 /dev/ashmem/gralloc-buffer (deleted)
465a4000-465e4000 rwxp 00000000 00:07 1157 /dev/ashmem/dalvik-heap-bitmap/mark/2 (deleted)
471a1000-471ec000 rwxs 00000000 00:07 704 /dev/ashmem/gralloc-buffer (deleted)
471ec000-4727b000 rwxs 00000000 00:07 708 /dev/ashmem/gralloc-buffer (deleted)
4800e000-4810e000 rwxs 00000000 00:07 761 /dev/ashmem/CursorWindow (deleted)
48489000-484d4000 rwxs 00000000 00:07 839 /dev/ashmem/gralloc-buffer (deleted)
We can see that a lot of different types of shared memory categories under the /dev/ashmem virtual drives.
The role and design of the system_server is blogged here:
http://www.androidenea.com/2009/07/system-server-in-android.html
http://www.androidenea.com/2009/12/adding-system-server-to-android.html
And looking the contents of the frameworks/base/cmds/system_server/system_main.cpp file, which implement the system_server module, it mainly called system_init() in system_init.cpp:
extern "C" status_t system_init()
{
LOGI("Entered system_init()");
sp<ProcessState> proc(ProcessState::self());
sp<IServiceManager> sm = defaultServiceManager();
LOGI("ServiceManager: %p\n", sm.get());
sp<GrimReaper> grim = new GrimReaper();
sm->asBinder()->linkToDeath(grim, grim.get(), 0);
char propBuf[PROPERTY_VALUE_MAX];
property_get("system_init.startsurfaceflinger", propBuf, "1");
if (strcmp(propBuf, "1") == 0) {
// Start the SurfaceFlinger
SurfaceFlinger::instantiate();
}
// Start the sensor service
SensorService::instantiate();
// On the simulator, audioflinger et al don't get started the
// same way as on the device, and we need to start them here
if (!proc->supportsProcesses()) {
// Start the AudioFlinger
AudioFlinger::instantiate();
// Start the media playback service
MediaPlayerService::instantiate();
// Start the camera service
CameraService::instantiate();
// Start the audio policy service
AudioPolicyService::instantiate();
}
// And now start the Android runtime. We have to do this bit
// of nastiness because the Android runtime initialization requires
// some of the core system services to already be started.
// All other servers should just start the Android runtime at
// the beginning of their processes's main(), before calling
// the init function.
LOGI("System server: starting Android runtime.\n");
AndroidRuntime* runtime = AndroidRuntime::getRuntime();
LOGI("System server: starting Android services.\n");
runtime->callStatic("com/android/server/SystemServer", "init2");=========================>SystemServer running under Dalvik JVM.
// If running in our own process, just go into the thread
// pool. Otherwise, call the initialization finished
// func to let this process continue its initilization.
if (proc->supportsProcesses()) {
LOGI("System server: entering thread pool.\n");
ProcessState::self()->startThreadPool();
IPCThreadState::self()->joinThreadPool();
LOGI("System server: exiting thread pool.\n");
}
return NO_ERROR;
}
And looking into the SystemServer.java implementation:
String factoryTestStr = SystemProperties.get("ro.factorytest");
int factoryTest = "".equals(factoryTestStr) ? SystemServer.FACTORY_TEST_OFF
: Integer.parseInt(factoryTestStr);
LightsService lights = null;
PowerManagerService power = null;
BatteryService battery = null;
ConnectivityService connectivity = null;
IPackageManager pm = null;
Context context = null;
WindowManagerService wm = null;
BluetoothService bluetooth = null;
BluetoothA2dpService bluetoothA2dp = null;
HeadsetObserver headset = null;
DockObserver dock = null;
UsbObserver usb = null;
UiModeManagerService uiMode = null;
RecognitionManagerService recognition = null;
ThrottleService throttle = null;
// Critical services...
try {
Slog.i(TAG, "Entropy Service");
ServiceManager.addService("entropy", new EntropyService());
Slog.i(TAG, "Power Manager");
power = new PowerManagerService();
ServiceManager.addService(Context.POWER_SERVICE, power);
Slog.i(TAG, "Activity Manager");
context = ActivityManagerService.main(factoryTest);
Slog.i(TAG, "Telephony Registry");
ServiceManager.addService("telephony.registry", new TelephonyRegistry(context));
AttributeCache.init(context);
Slog.i(TAG, "Package Manager");
pm = PackageManagerService.main(context,
factoryTest != SystemServer.FACTORY_TEST_OFF);
ActivityManagerService.setSystemProcess();
mContentResolver = context.getContentResolver();
// The AccountManager must come before the ContentService
try {
Slog.i(TAG, "Account Manager");
ServiceManager.addService(Context.ACCOUNT_SERVICE,
new AccountManagerService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Account Manager", e);
}
Slog.i(TAG, "Content Manager");
ContentService.main(context,
factoryTest == SystemServer.FACTORY_TEST_LOW_LEVEL);
Slog.i(TAG, "System Content Providers");
ActivityManagerService.installSystemProviders();
Slog.i(TAG, "Battery Service");
battery = new BatteryService(context);
ServiceManager.addService("battery", battery);
Slog.i(TAG, "Lights Service");
lights = new LightsService(context);
Slog.i(TAG, "Vibrator Service");
ServiceManager.addService("vibrator", new VibratorService(context));
// only initialize the power service after we have started the
// lights service, content providers and the battery service.
power.init(context, lights, ActivityManagerService.getDefault(), battery);
Slog.i(TAG, "Alarm Manager");
AlarmManagerService alarm = new AlarmManagerService(context);
ServiceManager.addService(Context.ALARM_SERVICE, alarm);
Slog.i(TAG, "Init Watchdog");
Watchdog.getInstance().init(context, battery, power, alarm,
ActivityManagerService.self());
Slog.i(TAG, "Window Manager");
wm = WindowManagerService.main(context, power,
factoryTest != SystemServer.FACTORY_TEST_LOW_LEVEL);
ServiceManager.addService(Context.WINDOW_SERVICE, wm);
((ActivityManagerService)ServiceManager.getService("activity"))
.setWindowManager(wm);
// Skip Bluetooth if we have an emulator kernel
// TODO: Use a more reliable check to see if this product should
// support Bluetooth - see bug 988521
if (SystemProperties.get("ro.kernel.qemu").equals("1")) {
Slog.i(TAG, "Registering null Bluetooth Service (emulator)");
ServiceManager.addService(BluetoothAdapter.BLUETOOTH_SERVICE, null);
} else if (factoryTest == SystemServer.FACTORY_TEST_LOW_LEVEL) {
Slog.i(TAG, "Registering null Bluetooth Service (factory test)");
ServiceManager.addService(BluetoothAdapter.BLUETOOTH_SERVICE, null);
} else {
Slog.i(TAG, "Bluetooth Service");
bluetooth = new BluetoothService(context);
ServiceManager.addService(BluetoothAdapter.BLUETOOTH_SERVICE, bluetooth);
bluetooth.initAfterRegistration();
bluetoothA2dp = new BluetoothA2dpService(context, bluetooth);
ServiceManager.addService(BluetoothA2dpService.BLUETOOTH_A2DP_SERVICE,
bluetoothA2dp);
int bluetoothOn = Settings.Secure.getInt(mContentResolver,
Settings.Secure.BLUETOOTH_ON, 0);
if (bluetoothOn > 0) {
bluetooth.enable();
}
}
} catch (RuntimeException e) {
Slog.e("System", "Failure starting core service", e);
}
DevicePolicyManagerService devicePolicy = null;
StatusBarManagerService statusBar = null;
InputMethodManagerService imm = null;
AppWidgetService appWidget = null;
NotificationManagerService notification = null;
WallpaperManagerService wallpaper = null;
LocationManagerService location = null;
if (factoryTest != SystemServer.FACTORY_TEST_LOW_LEVEL) {
try {
Slog.i(TAG, "Device Policy");
devicePolicy = new DevicePolicyManagerService(context);
ServiceManager.addService(Context.DEVICE_POLICY_SERVICE, devicePolicy);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting DevicePolicyService", e);
}
try {
Slog.i(TAG, "Status Bar");
statusBar = new StatusBarManagerService(context);
ServiceManager.addService(Context.STATUS_BAR_SERVICE, statusBar);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting StatusBarManagerService", e);
}
try {
Slog.i(TAG, "Clipboard Service");
ServiceManager.addService(Context.CLIPBOARD_SERVICE,
new ClipboardService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Clipboard Service", e);
}
try {
Slog.i(TAG, "Input Method Service");
imm = new InputMethodManagerService(context, statusBar);
ServiceManager.addService(Context.INPUT_METHOD_SERVICE, imm);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Input Manager Service", e);
}
try {
Slog.i(TAG, "NetStat Service");
ServiceManager.addService("netstat", new NetStatService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting NetStat Service", e);
}
try {
Slog.i(TAG, "NetworkManagement Service");
ServiceManager.addService(
Context.NETWORKMANAGEMENT_SERVICE,
NetworkManagementService.create(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting NetworkManagement Service", e);
}
try {
Slog.i(TAG, "Connectivity Service");
connectivity = ConnectivityService.getInstance(context);
ServiceManager.addService(Context.CONNECTIVITY_SERVICE, connectivity);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Connectivity Service", e);
}
try {
Slog.i(TAG, "Throttle Service");
throttle = new ThrottleService(context);
ServiceManager.addService(
Context.THROTTLE_SERVICE, throttle);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting ThrottleService", e);
}
try {
Slog.i(TAG, "Accessibility Manager");
ServiceManager.addService(Context.ACCESSIBILITY_SERVICE,
new AccessibilityManagerService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Accessibility Manager", e);
}
try {
/*
* NotificationManagerService is dependant on MountService,
* (for media / usb notifications) so we must start MountService first.
*/
Slog.i(TAG, "Mount Service");
ServiceManager.addService("mount", new MountService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Mount Service", e);
}
try {
Slog.i(TAG, "Notification Manager");
notification = new NotificationManagerService(context, statusBar, lights);
ServiceManager.addService(Context.NOTIFICATION_SERVICE, notification);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Notification Manager", e);
}
try {
Slog.i(TAG, "Device Storage Monitor");
ServiceManager.addService(DeviceStorageMonitorService.SERVICE,
new DeviceStorageMonitorService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting DeviceStorageMonitor service", e);
}
try {
Slog.i(TAG, "Location Manager");
location = new LocationManagerService(context);
ServiceManager.addService(Context.LOCATION_SERVICE, location);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Location Manager", e);
}
try {
Slog.i(TAG, "Search Service");
ServiceManager.addService(Context.SEARCH_SERVICE,
new SearchManagerService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Search Service", e);
}
if (INCLUDE_DEMO) {
Slog.i(TAG, "Installing demo data...");
(new DemoThread(context)).start();
}
try {
Slog.i(TAG, "DropBox Service");
ServiceManager.addService(Context.DROPBOX_SERVICE,
new DropBoxManagerService(context, new File("/data/system/dropbox")));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting DropBoxManagerService", e);
}
try {
Slog.i(TAG, "Wallpaper Service");
wallpaper = new WallpaperManagerService(context);
ServiceManager.addService(Context.WALLPAPER_SERVICE, wallpaper);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Wallpaper Service", e);
}
try {
Slog.i(TAG, "Audio Service");
ServiceManager.addService(Context.AUDIO_SERVICE, new AudioService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Audio Service", e);
}
try {
Slog.i(TAG, "Headset Observer");
// Listen for wired headset changes
headset = new HeadsetObserver(context);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting HeadsetObserver", e);
}
try {
Slog.i(TAG, "Dock Observer");
// Listen for dock station changes
dock = new DockObserver(context, power);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting DockObserver", e);
}
try {
Slog.i(TAG, "USB Observer");
// Listen for USB changes
usb = new UsbObserver(context);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting UsbObserver", e);
}
try {
Slog.i(TAG, "UI Mode Manager Service");
// Listen for UI mode changes
uiMode = new UiModeManagerService(context);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting UiModeManagerService", e);
}
try {
Slog.i(TAG, "Backup Service");
ServiceManager.addService(Context.BACKUP_SERVICE,
new BackupManagerService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Backup Service", e);
}
try {
Slog.i(TAG, "AppWidget Service");
appWidget = new AppWidgetService(context);
ServiceManager.addService(Context.APPWIDGET_SERVICE, appWidget);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting AppWidget Service", e);
}
try {
Slog.i(TAG, "Recognition Service");
recognition = new RecognitionManagerService(context);
} catch (Throwable e) {
Slog.e(TAG, "Failure starting Recognition Service", e);
}
try {
Slog.i(TAG, "DiskStats Service");
ServiceManager.addService("diskstats", new DiskStatsService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting DiskStats Service", e);
}
}
And extracting from logcat output (via “logcat” inside “adb shell” environment):
I/SystemServer( 52): Entered the Android system server!
I/SystemServer( 52): Entropy Service
I/SystemServer( 52): Power Manager
I/SystemServer( 52): Activity Manager
I/SystemServer( 52): Telephony Registry
I/SystemServer( 52): Package Manager
I/SystemServer( 52): Account Manager
I/SystemServer( 52): Content Manager
I/SystemServer( 52): System Content Providers
I/SystemServer( 52): Battery Service
I/SystemServer( 52): Hardware Service
I/SystemServer( 52): Alarm Manager
I/SystemServer( 52): Init Watchdog
I/SystemServer( 52): Sensor Service
I/SystemServer( 52): Window Manager
I/SystemServer( 52): Registering null Bluetooth Service (emulator)
E/System ( 52): at com.android.server.ServerThread.run(SystemServer.java:176)
I/SystemServer( 52): Status Bar
I/SystemServer( 52): Clipboard Service
I/SystemServer( 52): Input Method Service
I/SystemServer( 52): NetStat Service
I/SystemServer( 52): Connectivity Service
I/SystemServer( 52): Accessibility Manager
I/SystemServer( 52): Notification Manager
I/SystemServer( 52): Mount Service
I/SystemServer( 52): Device Storage Monitor
I/SystemServer( 52): Location Manager
I/SystemServer( 52): Search Service
I/SystemServer( 52): Checkin Service
W/SystemServer( 52): Using fallback Checkin Service.
I/SystemServer( 52): Wallpaper Service
I/SystemServer( 52): Audio Service
I/SystemServer( 52): Headset Observer
I/SystemServer( 52): Dock Observer
I/SystemServer( 52): Backup Service
I/SystemServer( 52): AppWidget Service
I/SystemServer( 52): Making services ready
Hm….understand? Only a little!!!!! Essentially adding all essential services and running it. And if you need to add a new service to SystemServer (VERY GOOD READ):
http://www.androidenea.com/2009/12/adding-system-server-to-android.html
Other system_server related blogs:
http://cphacker0901.wordpress.com/category/google-android/page/2/ (with a good diagram summary)
http://justanapplication.wordpress.com/2009/08/21/a-standalone-android-runtime-systemserver-startup/
http://justanapplication.wordpress.com/2009/08/19/a-standalone-android-runtime-getting-started/
http://www.google.com/search?num=100&hl=en&q=android+site:wordpress.com+system_server&aq=f&aqi=&aql=&oq=
http://www.google.com/search?num=100&hl=en&q=android+site:blogspot.com+system_server&aq=f&aqi=&aql=&oq=
My Technical Blog 