--- a/b2g/chrome/content/shell.js
+++ b/b2g/chrome/content/shell.js
@@ -9,16 +9,17 @@ const Ci = Components.interfaces;
 const Cu = Components.utils;
 const Cr = Components.results;
 
 Cu.import('resource://gre/modules/XPCOMUtils.jsm');
 Cu.import('resource://gre/modules/Services.jsm');
 Cu.import('resource://gre/modules/ContactService.jsm');
 Cu.import('resource://gre/modules/SettingsChangeNotifier.jsm');
 Cu.import('resource://gre/modules/Webapps.jsm');
+Cu.import('resource://gre/modules/AlarmService.jsm');
 
 XPCOMUtils.defineLazyServiceGetter(Services, 'env',
                                    '@mozilla.org/process/environment;1',
                                    'nsIEnvironment');
 
 XPCOMUtils.defineLazyServiceGetter(Services, 'ss',
                                    '@mozilla.org/content/style-sheet-service;1',
                                    'nsIStyleSheetService');

new file mode 100644
--- /dev/null
+++ b/dom/alarm/AlarmService.jsm
@@ -0,0 +1,299 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+/* static functions */
+const DEBUG = false;
+
+function debug(aStr) {
+  if (DEBUG)
+    dump("AlarmService: " + aStr + "\n");
+}
+
+const { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/AlarmDB.jsm");
+
+let EXPORTED_SYMBOLS = ["AlarmService"];
+
+XPCOMUtils.defineLazyGetter(this, "ppmm", function() {
+  return Cc["@mozilla.org/parentprocessmessagemanager;1"].getService(Ci.nsIFrameMessageManager);
+});
+
+let myGlobal = this;
+
+let AlarmService = {
+  init: function init() {
+    debug("init()");
+
+    this._currentTimezoneOffset = (new Date()).getTimezoneOffset();
+
+    let alarmHalService = this._alarmHalService = Cc["@mozilla.org/alarmHalService;1"].getService(Ci.nsIAlarmHalService);
+    alarmHalService.setAlarmFiredCb(this._onAlarmFired.bind(this));
+    alarmHalService.setTimezoneChangedCb(this._onTimezoneChanged.bind(this));
+
+    // add the messages to be listened
+    const messages = ["AlarmsManager:GetAll", "AlarmsManager:Add", "AlarmsManager:Remove"];
+    messages.forEach(function addMessage(msgName) {
+        ppmm.addMessageListener(msgName, this);
+    }.bind(this));
+
+    // set the indexeddb database
+    let idbManager = Components.classes["@mozilla.org/dom/indexeddb/manager;1"].getService(Ci.nsIIndexedDatabaseManager);
+    idbManager.initWindowless(myGlobal);
+    this._db = new AlarmDB(myGlobal);
+    this._db.init(myGlobal);
+
+    // variable to save alarms waiting to be set
+    this._alarmQueue = [];
+
+    this._restoreAlarmsFromDb();
+  },
+
+  // getter/setter to access the current alarm set in system
+  _alarm: null,
+  get _currentAlarm() {
+    return this._alarm;
+  },
+  set _currentAlarm(aAlarm) {
+    this._alarm = aAlarm;
+    if (!aAlarm)
+      return;
+
+    if (!this._alarmHalService.setAlarm(this._getAlarmTime(aAlarm) / 1000, 0))
+      throw Components.results.NS_ERROR_FAILURE;
+  },
+
+  receiveMessage: function receiveMessage(aMessage) {
+    debug("receiveMessage(): " + aMessage.name);
+
+    let json = aMessage.json;
+    switch (aMessage.name) {
+      case "AlarmsManager:GetAll":
+        this._db.getAll(
+          function getAllSuccessCb(aAlarms) {
+            debug("Callback after getting alarms from database: " + JSON.stringify(aAlarms));
+            ppmm.sendAsyncMessage(
+              "AlarmsManager:GetAll:Return:OK", 
+              { requestID: json.requestID, alarms: aAlarms }
+            ); 
+          }.bind(this),
+          function getAllErrorCb(aErrorMsg) {
+            ppmm.sendAsyncMessage(
+              "AlarmsManager:GetAll:Return:KO", 
+              { requestID: json.requestID, errorMsg: aErrorMsg }
+            );
+          }.bind(this)
+        );
+        break;
+
+      case "AlarmsManager:Add":
+        // prepare a record for the new alarm to be added
+        let newAlarm = {
+          date: json.date, 
+          ignoreTimezone: json.ignoreTimezone, 
+          timezoneOffset: this._currentTimezoneOffset, 
+          data: json.data
+        };
+
+        this._db.add(
+          newAlarm,
+          function addSuccessCb(aNewId) {
+            debug("Callback after adding alarm in database.");
+
+            newAlarm['id'] = aNewId;
+            let newAlarmTime = this._getAlarmTime(newAlarm);
+
+            if (newAlarmTime <= Date.now()) {
+              debug("Adding a alarm that has past time. Don't set it in system.");
+              this._debugCurrentAlarm();
+              return;
+            }
+
+            // if there is no alarm being set in system, set the new alarm
+            if (this._currentAlarm == null) {
+              this._currentAlarm = newAlarm;
+              this._debugCurrentAlarm();
+              return;
+            }
+
+            // if the new alarm is earlier than the current alarm
+            // swap them and push the previous alarm back to queue
+            let alarmQueue = this._alarmQueue;
+            let currentAlarmTime = this._getAlarmTime(this._currentAlarm);
+            if (newAlarmTime < currentAlarmTime) {
+              alarmQueue.unshift(this._currentAlarm);
+              this._currentAlarm = newAlarm;
+              this._debugCurrentAlarm();
+              return;
+            }
+
+            //push the new alarm in the queue
+            alarmQueue.push(newAlarm);
+            alarmQueue.sort(this._sortAlarmByTimeStamps.bind(this));
+            this._debugCurrentAlarm();
+
+            ppmm.sendAsyncMessage(
+              "AlarmsManager:Add:Return:OK", 
+              { requestID: json.requestID, id: aNewId }
+            );
+          }.bind(this),
+          function addErrorCb(aErrorMsg) {
+            ppmm.sendAsyncMessage(
+              "AlarmsManager:Add:Return:KO", 
+              { requestID: json.requestID, errorMsg: aErrorMsg }
+            );
+          }.bind(this)
+        );
+        break;
+
+      case "AlarmsManager:Remove":
+        this._db.remove(
+          json.id,
+          function removeSuccessCb() {
+            debug("Callback after removing alarm from database.");
+
+            // if there is no alarm being set
+            if (!this._currentAlarm) {
+              this._debugCurrentAlarm();
+              return;
+            }
+
+            // check if the alarm to be removed is in the queue
+            let alarmQueue = this._alarmQueue;
+            if (this._currentAlarm.id != json.id) {
+              for (let i = 0; i < alarmQueue.length; i++) {
+                if (alarmQueue[i].id == json.id) {
+                  alarmQueue.splice(i, 1);
+                  break;
+                }
+              }
+              this._debugCurrentAlarm();
+              return;
+            }
+
+            // the alarm to be removed is the current alarm
+            // reset the next alarm from queue if any
+            if (alarmQueue.length) {
+              this._currentAlarm = alarmQueue.shift();
+              this._debugCurrentAlarm();
+              return;
+            }
+
+            // no alarm waiting to be set in the queue
+            this._currentAlarm = null;
+            this._debugCurrentAlarm();
+          }.bind(this),
+          function removeErrorCb(aErrorMsg) {
+            throw Components.results.NS_ERROR_NOT_IMPLEMENTED;
+          }
+        );
+        break;
+
+      default:
+        throw Components.results.NS_ERROR_NOT_IMPLEMENTED;
+        break;
+    }
+  },
+
+  _onAlarmFired: function _onAlarmFired() {
+    debug("_onAlarmFired()");
+
+    if (this._currentAlarm) {
+      debug("Fire system intent: " + JSON.stringify(this._currentAlarm));
+      // TODO Fire a system message, see bug 755245
+      this._currentAlarm = null;
+    }
+
+    // reset the next alarm from the queue
+    let nowTime = Date.now();
+    let alarmQueue = this._alarmQueue;
+    while (alarmQueue.length > 0) {
+      let nextAlarm = alarmQueue.shift();
+      let nextAlarmTime = this._getAlarmTime(nextAlarm);
+
+      // if the next alarm has been expired, directly 
+      // fire system intent for it instead of setting it
+      if (nextAlarmTime <= nowTime) {
+        debug("Fire system intent: " + JSON.stringify(nextAlarm));
+        // TODO Fire a system message, see bug 755245
+      } else {
+        this._currentAlarm = nextAlarm;
+        break;
+      }
+    }
+    this._debugCurrentAlarm();
+  },
+
+  _onTimezoneChanged: function _onTimezoneChanged(aTimezoneOffset) {
+    debug("_onTimezoneChanged()");
+
+    this._currentTimezoneOffset = aTimezoneOffset;
+    this._restoreAlarmsFromDb();
+  },
+
+  _restoreAlarmsFromDb: function _restoreAlarmsFromDb() {
+    debug("_restoreAlarmsFromDb()");
+
+    this._db.getAll(
+      function getAllSuccessCb(aAlarms) {
+        debug("Callback after getting alarms from database: " + JSON.stringify(aAlarms));
+
+        // clear any alarms set or queued in the cache
+        let alarmQueue = this._alarmQueue;
+        alarmQueue.length = 0;
+        this._currentAlarm = null;
+        
+        // only add the alarm that is valid
+        let nowTime = Date.now();
+        aAlarms.forEach(function addAlarm(aAlarm) {
+          if (this._getAlarmTime(aAlarm) > nowTime)
+            alarmQueue.push(aAlarm);
+        }.bind(this));
+
+        // set the next alarm from queue
+        if (alarmQueue.length) {
+          alarmQueue.sort(this._sortAlarmByTimeStamps.bind(this));
+          this._currentAlarm = alarmQueue.shift();
+        }
+
+        this._debugCurrentAlarm();
+      }.bind(this),
+      function getAllErrorCb(aErrorMsg) {
+        throw Components.results.NS_ERROR_NOT_IMPLEMENTED;
+      }
+    );
+  },
+
+  _getAlarmTime: function _getAlarmTime(aAlarm) {
+    let alarmTime = (new Date(aAlarm.date)).getTime();
+    
+    // For an alarm specified with "ignoreTimezone",
+    // it must be fired respect to the user's timezone.
+    // Supposing an alarm was set at 7:00pm at Tokyo,
+    // it must be gone off at 7:00pm respect to Paris' 
+    // local time when the user is located at Paris.
+    // We can adjust the alarm UTC time by calculating
+    // the difference of the orginal timezone and the 
+    // current timezone.
+    if (aAlarm.ignoreTimezone)
+       alarmTime += (this._currentTimezoneOffset - aAlarm.timezoneOffset) * 60000;
+
+    return alarmTime;
+  },
+
+  _sortAlarmByTimeStamps: function _sortAlarmByTimeStamps(aAlarm1, aAlarm2) {
+    return this._getAlarmTime(aAlarm1) - this._getAlarmTime(aAlarm2);
+  },
+
+  _debugCurrentAlarm: function _debugCurrentAlarm() {
+    debug("Current alarm: " + JSON.stringify(this._currentAlarm));
+    debug("Alarm queue: " + JSON.stringify(this._alarmQueue));
+  },
+}
+
+AlarmService.init();

--- a/dom/alarm/AlarmsManager.js
+++ b/dom/alarm/AlarmsManager.js
@@ -1,27 +1,36 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
+/* static functions */
+const DEBUG = false;
+
+function debug(aStr) {
+  if (DEBUG)
+    dump("AlarmsManager: " + aStr + "\n");
+}
+
 const { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/DOMRequestHelper.jsm");
 
 const ALARMSMANAGER_CONTRACTID = "@mozilla.org/alarmsManager;1";
 const ALARMSMANAGER_CID        = Components.ID("{fea1e884-9b05-11e1-9b64-87a7016c3860}");
 const nsIDOMMozAlarmsManager   = Ci.nsIDOMMozAlarmsManager;
 const nsIClassInfo             = Ci.nsIClassInfo;
 
 function AlarmsManager()
 {
+  debug("Constructor");
 }
 
 AlarmsManager.prototype = {
 
   __proto__: DOMRequestIpcHelper.prototype,
 
   classID : ALARMSMANAGER_CID,
 
@@ -29,47 +38,122 @@ AlarmsManager.prototype = {
 
   classInfo : XPCOMUtils.generateCI({ classID: ALARMSMANAGER_CID,
                                       contractID: ALARMSMANAGER_CONTRACTID,
                                       classDescription: "AlarmsManager",
                                       interfaces: [nsIDOMMozAlarmsManager],
                                       flags: nsIClassInfo.DOM_OBJECT }),
 
   add: function add(aDate, aRespectTimezone, aData) {
-    return null;
+    debug("add()");
+
+    let isIgnoreTimezone = true;
+    switch (aRespectTimezone) {
+      case "honorTimezone":
+        isIgnoreTimezone = false;
+        break;
+
+      case "ignoreTimezone":
+        isIgnoreTimezone = true;
+        break;
+
+      default:
+        throw Components.results.NS_ERROR_NOT_IMPLEMENTED;
+        break;
+    }
+
+    let request = this.createRequest();
+    this._cpmm.sendAsyncMessage(
+      "AlarmsManager:Add", 
+      { requestID: this.getRequestId(request), date: aDate, ignoreTimezone: isIgnoreTimezone, data: aData }
+    );
+    return request;
   },
 
   remove: function remove(aId) {
-    return;
+    debug("remove()");
+
+    return this._cpmm.sendSyncMessage(
+      "AlarmsManager:Remove", 
+      { id: aId }
+    );
   },
 
   getAll: function getAll() {
-    return null;
+    debug("getAll()");
+
+    let request = this.createRequest();
+    this._cpmm.sendAsyncMessage(
+      "AlarmsManager:GetAll", 
+      { requestID: this.getRequestId(request) }
+    );
+    return request;
   },
 
+  receiveMessage: function receiveMessage(aMessage) {
+    debug("receiveMessage(): " + aMessage.name);
+
+    let json = aMessage.json;
+    let request = this.getRequest(json.requestID);
+
+    if (!request) {
+      debug("No request stored! " + json.requestID);
+      return;
+    }
+
+    switch (aMessage.name) {
+      case "AlarmsManager:Add:Return:OK":
+        Services.DOMRequest.fireSuccess(request, json.id);
+        break;
+
+      case "AlarmsManager:GetAll:Return:OK":
+        Services.DOMRequest.fireSuccess(request, json.alarms);
+        break;
+
+      case "AlarmsManager:Add:Return:KO":
+        Services.DOMRequest.fireError(request, json.errorMsg);
+        break;
+
+      case "AlarmsManager:GetAll:Return:KO":
+        Services.DOMRequest.fireError(request, json.errorMsg);
+        break;
+
+      default:
+        debug("Wrong message: " + aMessage.name);
+        break;
+    }
+    this.removeRequest(json.requestID);
+   },
+
   // nsIDOMGlobalPropertyInitializer implementation
   init: function init(aWindow) {
+    debug("init()");
+
     // Set navigator.mozAlarms to null.
     if (!Services.prefs.getBoolPref("dom.mozAlarms.enabled"))
       return null;
 
     let principal = aWindow.document.nodePrincipal;
     let secMan = Cc["@mozilla.org/scriptsecuritymanager;1"].getService(Ci.nsIScriptSecurityManager);
 
     let perm = principal == secMan.getSystemPrincipal() ? 
       Ci.nsIPermissionManager.ALLOW_ACTION : Services.perms.testExactPermission(principal.URI, "alarms");
 
     // Only pages with perm set can use the alarms.
     this.hasPrivileges = perm == Ci.nsIPermissionManager.ALLOW_ACTION;
 
     if (!this.hasPrivileges)
       return null;
 
+    this._cpmm = Cc["@mozilla.org/childprocessmessagemanager;1"].getService(Ci.nsISyncMessageSender);
+
     // Add the valid messages to be listened.
-    this.initHelper(aWindow, []);
+    this.initHelper(aWindow, ["AlarmsManager:Add:Return:OK", "AlarmsManager:Add:Return:KO", 
+                              "AlarmsManager:GetAll:Return:OK", "AlarmsManager:GetAll:Return:KO"]);
   },
 
   // Called from DOMRequestIpcHelper.
   uninit: function uninit() {
+    debug("uninit()");
   },
 }
 
 const NSGetFactory = XPCOMUtils.generateNSGetFactory([AlarmsManager])

--- a/dom/alarm/Makefile.in
+++ b/dom/alarm/Makefile.in
@@ -22,16 +22,17 @@ EXPORTS_NAMESPACES = mozilla/dom/alarm
 
 EXTRA_COMPONENTS =       \
   AlarmsManager.js       \
   AlarmsManager.manifest \
   $(NULL)
 
 EXTRA_JS_MODULES = \
   AlarmDB.jsm      \
+  AlarmService.jsm \
   $(NULL)
 
 XPIDLSRCS =               \
   nsIDOMAlarmsManager.idl \
   nsIAlarmHalService.idl  \
   $(NULL)
 
 EXPORTS_mozilla/dom/alarm = \