diff --git a/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
index e26cb36..9c1daf9 100644
--- a/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -2452,15 +2452,32 @@ function drupal_container(Container $reset = NULL) {
     //   bootstrap configuration *file* to allow to set/override this very
     //   lowest of low level configuration.
     $container->setParameter('config.storage.options', array(
-      'connection' => 'default',
-      'target' => 'default',
+      'Drupal\Core\Config\FileStorage' => array(
+        'directory' => config_get_config_directory(),
+      ),
+      'Drupal\Core\Config\CacheStorage' => array(
+        'backend' => 'Drupal\Core\Cache\DatabaseBackend',
+        // @todo Add and replace with 'config' default bin.
+        'bin' => 'cache',
+      ),
     ));
-    $container->register('config.storage', 'Drupal\Core\Config\DatabaseStorage')
+    // @todo Use this for exporting your current config in the DB... ;)
+    #$container->register('config.storage', 'Drupal\Core\Config\MultiStorage')
+    $container->register('config.storage', 'Drupal\Core\Config\CachedFileStorage')
       ->addArgument('%config.storage.options%');
 
     // Register configuration object factory.
     $container->register('config.factory', 'Drupal\Core\Config\ConfigFactory')
       ->addArgument(new Reference('config.storage'));
+
+    // Register configuration state.
+    $container->setParameter('config.state.options', array(
+      'connection' => 'default',
+      'target' => 'default',
+      'table' => 'config',
+    ));
+    $container->register('config.state', 'Drupal\Core\Config\DatabaseStorage')
+      ->addArgument('%config.state.options%');
   }
   return $container;
 }
diff --git a/core/includes/config.inc b/core/includes/config.inc
index f2fcd39..14f41f9 100644
--- a/core/includes/config.inc
+++ b/core/includes/config.inc
@@ -17,9 +17,6 @@
  *   The extension type; e.g., 'module' or 'theme'.
  * @param string $name
  *   The name of the module or theme to install default configuration for.
- *
- * @todo Make this acknowledge other storage engines rather than having
- *   SQL be hardcoded.
  */
 function config_install_default_config($type, $name) {
   $config_dir = drupal_get_path($type, $name) . '/config';
@@ -43,7 +40,9 @@ function config_install_default_config($type, $name) {
 }
 
 /**
- * @todo Modules need a way to access the active store, whatever it is.
+ * Gets configuration object names starting with a given prefix.
+ *
+ * @see Drupal\Core\Config\StorageInterface::listAll()
  */
 function config_get_storage_names_with_prefix($prefix = '') {
   return drupal_container()->get('config.storage')->listAll($prefix);
@@ -129,15 +128,15 @@ function config_sync_changes(array $config_changes, StorageInterface $source_sto
 }
 
 /**
- * Imports configuration from FileStorage to the active store.
+ * Imports configuration into the active store.
  *
  * @return bool|null
  *   TRUE if configuration was imported successfully, FALSE in case of a
  *   synchronization error, or NULL if there are no changes to synchronize.
  */
 function config_import() {
-  // Retrieve a list of differences between FileStorage and the active store.
-  $source_storage = new FileStorage();
+  // Retrieve a list of differences between last known state and active store.
+  $source_storage = drupal_container()->get('config.state');
   $target_storage = drupal_container()->get('config.storage');
 
   $config_changes = config_sync_get_changes($source_storage, $target_storage);
@@ -217,12 +216,14 @@ function config_import_invoke_owner(array $config_changes, StorageInterface $sou
 }
 
 /**
- * Exports configuration from the active store to FileStorage.
+ * Updates the last known state with the active store configuration.
+ *
+ * @todo config_export() is a misnomer now. Rename to config_state_update().
  */
 function config_export() {
-  // Retrieve a list of differences between the active store and FileStorage.
+  // Retrieve a list of differences between active store and last known state.
   $source_storage = drupal_container()->get('config.storage');
-  $target_storage = new FileStorage();
+  $target_storage = drupal_container()->get('config.state');
 
   $config_changes = config_sync_get_changes($source_storage, $target_storage);
   if (empty($config_changes)) {
diff --git a/core/includes/module.inc b/core/includes/module.inc
index ab45576..6c4f24d 100644
--- a/core/includes/module.inc
+++ b/core/includes/module.inc
@@ -6,7 +6,7 @@
  */
 
 use Drupal\Component\Graph\Graph;
-use Drupal\Core\Config\DatabaseStorage;
+use Drupal\Core\Config\NullStorage;
 
 /**
  * Load all the modules that have been enabled in the system table.
@@ -622,19 +622,26 @@ function module_uninstall($module_list = array(), $uninstall_dependents = TRUE)
     $module_list = array_keys($module_list);
   }
 
-  $storage = new DatabaseStorage();
+  $source_storage = new NullStorage();
+  $target_storage = drupal_container()->get('config.storage');
   foreach ($module_list as $module) {
+    // Remove all configuration belonging to the module.
+    $config_changes = $target_storage->listAll($module . '.');
+    if (!empty($config_changes)) {
+      $config_changes = array(
+        'delete' => $config_changes,
+        'change' => array(),
+        'create' => array(),
+      );
+      $remaining_changes = config_import_invoke_owner($config_changes, $source_storage, $target_storage);
+      config_sync_changes($remaining_changes, $source_storage, $target_storage);
+    }
+
     // Uninstall the module.
     module_load_install($module);
     module_invoke($module, 'uninstall');
     drupal_uninstall_schema($module);
 
-    // Remove all configuration belonging to the module.
-    $config_names = $storage->listAll($module . '.');
-    foreach ($config_names as $config_name) {
-      config($config_name)->delete();
-    }
-
     watchdog('system', '%module module uninstalled.', array('%module' => $module), WATCHDOG_INFO);
     drupal_set_installed_schema_version($module, SCHEMA_UNINSTALLED);
   }
diff --git a/core/lib/Drupal/Core/Config/CacheStorage.php b/core/lib/Drupal/Core/Config/CacheStorage.php
new file mode 100644
index 0000000..6e77ae2
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/CacheStorage.php
@@ -0,0 +1,112 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\Core\Config\CacheStorage.
+ */
+
+namespace Drupal\Core\Config;
+
+/**
+ * Defines the Cache storage controller.
+ */
+class CacheStorage implements StorageInterface {
+
+  /**
+   * Cache backend options for this storage controller.
+   *
+   * - backend: The cache backend to use.
+   * - bin: The cache bin to use.
+   *
+   * @var array
+   */
+  protected $options;
+
+  /**
+   * The instantiated Cache backend.
+   *
+   * @var Drupal\Core\Cache\CacheBackendInterface
+   */
+  protected $storage;
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::__construct().
+   */
+  public function __construct(array $options = array()) {
+    $options += array(
+      'backend' => 'Drupal\Core\Cache\DatabaseBackend',
+      'bin' => 'config',
+    );
+    $this->options = $options;
+  }
+
+  /**
+   * Returns the instantiated Cache backend to use.
+   */
+  protected function getBackend() {
+    if (!isset($this->storage)) {
+      $this->storage = new $this->options['backend']($this->options['bin']);
+    }
+    return $this->storage;
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::exists().
+   */
+  public function exists($name) {
+    return (bool) $this->getBackend()->get($name);
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::read().
+   */
+  public function read($name) {
+    if ($cache = $this->getBackend()->get($name)) {
+      return $cache->data;
+    }
+    return FALSE;
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::write().
+   */
+  public function write($name, array $data) {
+    $this->getBackend()->set($name, $data, CACHE_PERMANENT, array('config' => array($name)));
+    return TRUE;
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::delete().
+   */
+  public function delete($name) {
+    $this->getBackend()->delete($name);
+    return TRUE;
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::encode().
+   */
+  public static function encode($data) {
+    return serialize($data);
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::decode().
+   *
+   * @throws ErrorException
+   *   unserialize() triggers E_NOTICE if the string cannot be unserialized.
+   */
+  public static function decode($raw) {
+    $data = @unserialize($raw);
+    return is_array($data) ? $data : FALSE;
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::listAll().
+   *
+   * Not supported by CacheBackendInterface.
+   */
+  public function listAll($prefix = '') {
+    return array();
+  }
+}
diff --git a/core/lib/Drupal/Core/Config/CachedFileStorage.php b/core/lib/Drupal/Core/Config/CachedFileStorage.php
new file mode 100644
index 0000000..7fbaef9
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/CachedFileStorage.php
@@ -0,0 +1,125 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\Core\Config\CachedFileStorage.
+ */
+
+namespace Drupal\Core\Config;
+
+use Drupal\Core\Config\FileStorage;
+
+/**
+ * Storage controller that uses FileStorage as canonical storage and
+ * DatabaseStorage as a cache (active store).
+ */
+class CachedFileStorage implements StorageInterface {
+
+  /**
+   * The configuration options for the sub-storage controllers.
+   *
+   * An associative array whose keys are the class names of the storage
+   * controllers to use, and whose values are the respective configuration
+   * options for each storage controller.
+   *
+   * Two array elements are expected. A key and definition for
+   * Drupal\Core\Config\FileStorage is required. The other element should point
+   * to another storage controller that is used as cache.
+   *
+   * @var array
+   */
+  protected $options;
+
+  /**
+   * The instantiated sub-storage controllers.
+   *
+   * @var array
+   */
+  protected $storages = array();
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::__construct().
+   */
+  public function __construct(array $options = array()) {
+    $this->options = $options;
+
+    $this->storages['file'] = new FileStorage($options['Drupal\Core\Config\FileStorage']);
+
+    unset($options['Drupal\Core\Config\FileStorage']);
+    list($active_class, $active_options) = each($options);
+    $this->storages['active'] = new $active_class($active_options);
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::exists().
+   */
+  public function exists($name) {
+    // A single filestat is faster than a complex cache lookup and possibly
+    // subsequent filestat.
+    return $this->storages['file']->exists($name);
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::read().
+   */
+  public function read($name) {
+    // Check the cache.
+    $data = $this->storages['active']->read($name);
+    // If the cache returns no result, check the file storage.
+    if ($data === FALSE) {
+      $data = $this->storages['file']->read($name);
+      // @todo Should the config object be cached if it does not exist?
+      if ($data !== FALSE) {
+        $this->storages['active']->write($name, $data);
+      }
+    }
+    return $data;
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::write().
+   */
+  public function write($name, array $data) {
+    $success = $this->storages['file']->write($name, $data);
+    $this->storages['active']->delete($name);
+    return $success;
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::delete().
+   */
+  public function delete($name) {
+    $success = TRUE;
+    foreach ($this->storages as $storage) {
+      if (!$storage->delete($name)) {
+        $success = FALSE;
+      }
+    }
+    return $success;
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::encode().
+   *
+   * @todo Remove encode() from StorageInterface.
+   */
+  public static function encode($data) {
+    return $this->storages['file']->encode($data);
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::decode().
+   *
+   * @todo Remove decode() from StorageInterface.
+   */
+  public static function decode($raw) {
+    return $this->storages['file']->decode($raw);
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::listAll().
+   */
+  public function listAll($prefix = '') {
+    return $this->storages['file']->listAll($prefix);
+  }
+}
diff --git a/core/lib/Drupal/Core/Config/Config.php b/core/lib/Drupal/Core/Config/Config.php
index 2f4d14a..c5423ca 100644
--- a/core/lib/Drupal/Core/Config/Config.php
+++ b/core/lib/Drupal/Core/Config/Config.php
@@ -270,6 +270,7 @@ public function sortByKey(array &$data) {
    * Deletes the configuration object.
    */
   public function delete() {
+    // @todo Consider to remove the pruning of data for Config::delete().
     $this->data = array();
     $this->storage->delete($this->name);
     $this->isNew = TRUE;
diff --git a/core/lib/Drupal/Core/Config/DatabaseStorage.php b/core/lib/Drupal/Core/Config/DatabaseStorage.php
index 92aea45..8ab64f6 100644
--- a/core/lib/Drupal/Core/Config/DatabaseStorage.php
+++ b/core/lib/Drupal/Core/Config/DatabaseStorage.php
@@ -44,6 +44,15 @@ protected function getConnection() {
   }
 
   /**
+   * Implements Drupal\Core\Config\StorageInterface::exists().
+   */
+  public function exists($name) {
+    return (bool) $this->getConnection()->queryRange('SELECT 1 FROM {config} WHERE name = :name', 0, 1, array(
+      ':name' => $name,
+    ), $this->options)->fetchField();
+  }
+
+  /**
    * Implements Drupal\Core\Config\StorageInterface::read().
    *
    * @throws PDOException
diff --git a/core/lib/Drupal/Core/Config/FileStorage.php b/core/lib/Drupal/Core/Config/FileStorage.php
index 033555d..727adef 100644
--- a/core/lib/Drupal/Core/Config/FileStorage.php
+++ b/core/lib/Drupal/Core/Config/FileStorage.php
@@ -54,10 +54,7 @@ public static function getFileExtension() {
   }
 
   /**
-   * Returns whether the configuration file exists.
-   *
-   * @return bool
-   *   TRUE if the configuration file exists, FALSE otherwise.
+   * Implements Drupal\Core\Config\StorageInterface::exists().
    */
   public function exists($name) {
     return file_exists($this->getFilePath($name));
diff --git a/core/lib/Drupal/Core/Config/MultiStorage.php b/core/lib/Drupal/Core/Config/MultiStorage.php
new file mode 100644
index 0000000..484501a
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/MultiStorage.php
@@ -0,0 +1,117 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\Core\Config\MultiStorage.
+ */
+
+namespace Drupal\Core\Config;
+
+/**
+ * Defines a storage controller that wraps multiple others.
+ *
+ * This storage controller has no actual storage attached to itself, but rather
+ * forwards the operations to one or more other storage controllers, depending
+ * on the operation being performed.
+ *
+ * The options define which other storage controllers are used, along with their
+ * respective options.
+ *
+ * Only the first defined storage controller is used for reading configuration.
+ * All writes and deletes are performed on all storage controllers.
+ */
+class MultiStorage implements StorageInterface {
+
+  /**
+   * The configuration options for the sub-storage controllers.
+   *
+   * An associative array whose keys are the class names of the storage
+   * controllers to use, and whose values are the respective configuration
+   * options for each storage controller.
+   *
+   * @var array
+   */
+  protected $options;
+
+  /**
+   * The instantiated sub-storage controllers.
+   *
+   * @var array
+   */
+  protected $storages = array();
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::__construct().
+   */
+  public function __construct(array $options = array()) {
+    foreach ($options as $storage_controller => $storage_options) {
+      $this->storages[] = new $storage_controller($storage_options);
+    }
+    $this->options = $options;
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::exists().
+   */
+  public function exists($name) {
+    return $this->storages[0]->exists($name);
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::read().
+   */
+  public function read($name) {
+    return $this->storages[0]->read($name);
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::write().
+   */
+  public function write($name, array $data) {
+    $success = TRUE;
+    foreach ($this->storages as $storage) {
+      if (!$storage->write($name, $data)) {
+        $success = FALSE;
+      }
+    }
+    return $success;
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::delete().
+   */
+  public function delete($name) {
+    $success = TRUE;
+    foreach ($this->storages as $storage) {
+      if (!$storage->delete($name)) {
+        $success = FALSE;
+      }
+    }
+    return $success;
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::encode().
+   *
+   * @todo Remove encode() from StorageInterface.
+   */
+  public static function encode($data) {
+    return $this->storages[0]->encode($data);
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::decode().
+   *
+   * @todo Remove decode() from StorageInterface.
+   */
+  public static function decode($raw) {
+    return $this->storages[0]->decode($raw);
+  }
+
+  /**
+   * Implements Drupal\Core\Config\StorageInterface::listAll().
+   */
+  public function listAll($prefix = '') {
+    return $this->storages[0]->listAll($prefix);
+  }
+}
diff --git a/core/lib/Drupal/Core/Config/NullStorage.php b/core/lib/Drupal/Core/Config/NullStorage.php
index fede4f0..2e1c06c 100644
--- a/core/lib/Drupal/Core/Config/NullStorage.php
+++ b/core/lib/Drupal/Core/Config/NullStorage.php
@@ -29,6 +29,13 @@ public function __construct(array $options = array()) {
   }
 
   /**
+   * Implements Drupal\Core\Config\StorageInterface::exists().
+   */
+  public function exists($name) {
+    return FALSE;
+  }
+
+  /**
    * Implements Drupal\Core\Config\StorageInterface::read().
    */
   public function read($name) {
diff --git a/core/lib/Drupal/Core/Config/StorageInterface.php b/core/lib/Drupal/Core/Config/StorageInterface.php
index 806ee87..4fb9869 100644
--- a/core/lib/Drupal/Core/Config/StorageInterface.php
+++ b/core/lib/Drupal/Core/Config/StorageInterface.php
@@ -25,6 +25,17 @@
   public function __construct(array $options = array());
 
   /**
+   * Returns whether a configuration object exists.
+   *
+   * @param string $name
+   *   The name of a configuration object to test.
+   *
+   * @return bool
+   *   TRUE if the configuration object exists, FALSE otherwise.
+   */
+  public function exists($name);
+
+  /**
    * Reads configuration data from the storage.
    *
    * @param string $name
diff --git a/core/modules/config/config.admin.inc b/core/modules/config/config.admin.inc
new file mode 100644
index 0000000..eefa104
--- /dev/null
+++ b/core/modules/config/config.admin.inc
@@ -0,0 +1,132 @@
+<?php
+
+/**
+ * @file
+ * Admin page callbacks for the config module.
+ */
+
+use Drupal\Core\Config\StorageInterface;
+
+/**
+ * Helper function to construct the storage changes in a configuration synchronization form.
+ *
+ * @param array $form
+ *   The form structure to add to. Passed by reference.
+ * @param array $form_state
+ *   The current state of the form. Passed by reference.
+ * @param Drupal\Core\Config\StorageInterface $source_storage
+ *   The source storage to retrieve differences from.
+ * @param Drupal\Core\Config\StorageInterface $target_storage
+ *   The target storage to compare differences to.
+ */
+function config_admin_sync_form(array &$form, array &$form_state, StorageInterface $source_storage, StorageInterface $target_storage) {
+  $config_changes = config_sync_get_changes($source_storage, $target_storage);
+  if (empty($config_changes)) {
+    $form['no_changes'] = array(
+      '#markup' => t('There are no configuration changes.'),
+    );
+    return $form;
+  }
+
+  foreach ($config_changes as $config_change_type => $config_files) {
+    if (empty($config_files)) {
+      continue;
+    }
+    $form[$config_change_type] = array(
+      '#type' => 'fieldset',
+      '#title' => $config_change_type . ' (' . count($config_files) . ')',
+      '#collapsible' => TRUE,
+    );
+    $form[$config_change_type]['config_files'] = array(
+      '#theme' => 'table',
+      '#header' => array('Name'),
+    );
+    foreach ($config_files as $config_file) {
+      $form[$config_change_type]['config_files']['#rows'][] = array($config_file);
+    }
+  }
+}
+
+/**
+ * Form constructor for configuration import form.
+ *
+ * @see config_admin_import_form_submit()
+ * @see config_import()
+ */
+function config_admin_import_form($form, &$form_state) {
+  // Retrieve a list of differences between last known state and active store.
+  $source_storage = drupal_container()->get('config.state');
+  $target_storage = drupal_container()->get('config.storage');
+
+  // Prevent users from deleting all configuration.
+  // If the source storage is empty, that signals the unique condition of not
+  // having exported anything at all, and thus no valid storage to compare the
+  // active storage against.
+  // @todo StorageInterface::listAll() can easily yield hundreds or even
+  //   thousands of entries; consider to add a dedicated isEmpty() method for
+  //   storage controllers.
+  $all = $source_storage->listAll();
+  if (empty($all)) {
+    form_set_error('', t('There is no base configuration. <a href="@export-url">Export</a> it first.', array(
+      '@export-url' => url('admin/config/development/sync/export'),
+    )));
+    return $form;
+  }
+
+  config_admin_sync_form($form, $form_state, $source_storage, $target_storage);
+
+  $form['actions'] = array('#type' => 'actions');
+  $form['actions']['submit'] = array(
+    '#type' => 'submit',
+    '#value' => t('Import'),
+  );
+  return $form;
+}
+
+/**
+ * Form submission handler for config_admin_import_form().
+ */
+function config_admin_import_form_submit($form, &$form_state) {
+  if (config_import()) {
+    drupal_set_message(t('The configuration was imported successfully.'));
+  }
+  else {
+    // Another request may be synchronizing configuration already. Wait for it
+    // to complete before returning the error, so already synchronized changes
+    // do not appear again.
+    lock_wait(__FUNCTION__);
+    drupal_set_message(t('The import failed due to an error. Any errors have been logged.'), 'error');
+  }
+}
+
+/**
+ * Form constructor for configuration export form.
+ *
+ * @see config_admin_export_form_submit()
+ * @see config_export()
+ *
+ * @todo "export" is a misnomer with config.state.
+ */
+function config_admin_export_form($form, &$form_state) {
+  // Retrieve a list of differences between active store and last known state.
+  $source_storage = drupal_container()->get('config.storage');
+  $target_storage = drupal_container()->get('config.state');
+
+  config_admin_sync_form($form, $form_state, $source_storage, $target_storage);
+
+  $form['actions'] = array('#type' => 'actions');
+  $form['actions']['submit'] = array(
+    '#type' => 'submit',
+    '#value' => t('Export'),
+  );
+  return $form;
+}
+
+/**
+ * Form submission handler for config_admin_export_form().
+ */
+function config_admin_export_form_submit($form, &$form_state) {
+  config_export();
+  drupal_set_message(t('The configuration was exported successfully.'));
+}
+
diff --git a/core/modules/config/config.info b/core/modules/config/config.info
index 380f17e..efab7a1 100644
--- a/core/modules/config/config.info
+++ b/core/modules/config/config.info
@@ -3,3 +3,4 @@ description = Allows administrators to manage configuration changes.
 package = Core
 version = VERSION
 core = 8.x
+configure = admin/config/development/sync
diff --git a/core/modules/config/config.module b/core/modules/config/config.module
index b3d9bbc..fd38fd2 100644
--- a/core/modules/config/config.module
+++ b/core/modules/config/config.module
@@ -1 +1,46 @@
 <?php
+
+/**
+ * @file
+ * Allows site administrators to modify configuration.
+ */
+
+/**
+ * Implements hook_permission().
+ */
+function config_permission() {
+  $permissions['synchronize configuration'] = array(
+    'title' => t('Synchronize configuration'),
+    'restrict access' => TRUE,
+  );
+  return $permissions;
+}
+
+/**
+ * Implements hook_menu().
+ */
+function config_menu() {
+  $items['admin/config/development/sync'] = array(
+    'title' => 'Synchronize configuration',
+    'description' => 'Synchronize configuration changes.',
+    'page callback' => 'drupal_get_form',
+    'page arguments' => array('config_admin_import_form'),
+    'access arguments' => array('synchronize configuration'),
+    'file' => 'config.admin.inc',
+  );
+  $items['admin/config/development/sync/import'] = array(
+    'title' => 'Import',
+    'type' => MENU_DEFAULT_LOCAL_TASK,
+    'weight' => -10,
+  );
+  $items['admin/config/development/sync/export'] = array(
+    'title' => 'Export',
+    'page callback' => 'drupal_get_form',
+    'page arguments' => array('config_admin_export_form'),
+    'access arguments' => array('synchronize configuration'),
+    'file' => 'config.admin.inc',
+    'type' => MENU_LOCAL_TASK,
+  );
+  return $items;
+}
+
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigImportTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigImportTest.php
index ec92fdf..0007284 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigImportTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigImportTest.php
@@ -73,22 +73,28 @@ function testNew() {
     $name = 'config_test.new';
     $dynamic_name = 'config_test.dynamic.new';
 
+    // Export.
+    config_export();
+
     // Verify the configuration to create does not exist yet.
+    $database_storage = new DatabaseStorage();
+    $this->assertIdentical($database_storage->exists($name), FALSE, $name . ' not found.');
+    $this->assertIdentical($database_storage->exists($dynamic_name), FALSE, $dynamic_name . ' not found.');
+
     $file_storage = new FileStorage();
     $this->assertIdentical($file_storage->exists($name), FALSE, $name . ' not found.');
     $this->assertIdentical($file_storage->exists($dynamic_name), FALSE, $dynamic_name . ' not found.');
 
-    // Export.
-    config_export();
-
     // Create new configuration objects.
-    $file_storage->write($name, array(
+    $original_name_data = array(
       'add_me' => 'new value',
-    ));
-    $file_storage->write($dynamic_name, array(
+    );
+    $file_storage->write($name, $original_name_data);
+    $original_dynamic_data = array(
       'id' => 'new',
       'label' => 'New',
-    ));
+    );
+    $file_storage->write($dynamic_name, $original_dynamic_data);
     $this->assertIdentical($file_storage->exists($name), TRUE, $name . ' found.');
     $this->assertIdentical($file_storage->exists($dynamic_name), TRUE, $dynamic_name . ' found.');
 
@@ -97,9 +103,9 @@ function testNew() {
 
     // Verify the values appeared.
     $config = config($name);
-    $this->assertIdentical($config->get('add_me'), 'new value');
+    $this->assertIdentical($config->get('add_me'), $original_name_data['add_me']);
     $config = config($dynamic_name);
-    $this->assertIdentical($config->get('label'), 'New');
+    $this->assertIdentical($config->get('label'), $original_dynamic_data['label']);
   }
 
   /**
@@ -112,17 +118,25 @@ function testUpdated() {
     // Export.
     config_export();
 
-    // Replace the file content of the existing configuration objects.
+    // Verify that the configuration objects to import exist.
+    $database_storage = new DatabaseStorage();
+    $this->assertIdentical($database_storage->exists($name), TRUE, $name . ' found.');
+    $this->assertIdentical($database_storage->exists($dynamic_name), TRUE, $dynamic_name . ' found.');
+
     $file_storage = new FileStorage();
     $this->assertIdentical($file_storage->exists($name), TRUE, $name . ' found.');
     $this->assertIdentical($file_storage->exists($dynamic_name), TRUE, $dynamic_name . ' found.');
-    $file_storage->write($name, array(
+
+    // Replace the file content of the existing configuration objects.
+    $original_name_data = array(
       'foo' => 'beer',
-    ));
-    $file_storage->write($dynamic_name, array(
+    );
+    $file_storage->write($name, $original_name_data);
+    $original_dynamic_data = array(
       'id' => 'default',
       'label' => 'Updated',
-    ));
+    );
+    $file_storage->write($dynamic_name, $original_dynamic_data);
 
     // Verify the active store still returns the default values.
     $config = config($name);
@@ -138,5 +152,9 @@ function testUpdated() {
     $this->assertIdentical($config->get('foo'), 'beer');
     $config = config($dynamic_name);
     $this->assertIdentical($config->get('label'), 'Updated');
+
+    // Verify that the original file content is still the same.
+    $this->assertIdentical($file_storage->read($name), $original_name_data);
+    $this->assertIdentical($file_storage->read($dynamic_name), $original_dynamic_data);
   }
 }
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php
new file mode 100644
index 0000000..3a9acdd
--- /dev/null
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php
@@ -0,0 +1,143 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\config\Tests\ConfigImportUITest.
+ */
+
+namespace Drupal\config\Tests;
+
+use Drupal\Core\Config\FileStorage;
+use Drupal\simpletest\WebTestBase;
+
+/**
+ * Tests importing configuration from files into active store.
+ */
+class ConfigImportUITest extends WebTestBase {
+  public static function getInfo() {
+    return array(
+      'name' => 'Import/Export UI',
+      'description' => 'Tests the user interface for importing/exporting configuration.',
+      'group' => 'Configuration',
+    );
+  }
+
+  function setUp() {
+    parent::setUp(array('config', 'config_test'));
+
+    $this->web_user = $this->drupalCreateUser(array('synchronize configuration'));
+    $this->drupalLogin($this->web_user);
+  }
+
+  /**
+   * Tests exporting configuration.
+   */
+  function testExport() {
+    $name = 'config_test.system';
+    $dynamic_name = 'config_test.dynamic.default';
+
+    // Verify the default configuration values exist.
+    $config = config($name);
+    $this->assertIdentical($config->get('foo'), 'bar');
+    $config = config($dynamic_name);
+    $this->assertIdentical($config->get('id'), 'default');
+
+    // Verify that both appear as deleted by default.
+    $this->drupalGet('admin/config/development/sync/export');
+    $this->assertText($name);
+    $this->assertText($dynamic_name);
+
+    // Export and verify that both do not appear anymore.
+    $this->drupalPost(NULL, array(), t('Export'));
+    $this->assertUrl('admin/config/development/sync/export');
+    $this->assertNoText($name);
+    $this->assertNoText($dynamic_name);
+
+    // Verify that there are no further changes to export.
+    $this->assertText(t('There are no configuration changes.'));
+
+    // Verify that the import screen shows no changes either.
+    $this->drupalGet('admin/config/development/sync');
+    $this->assertText(t('There are no configuration changes.'));
+  }
+
+  /**
+   * Tests importing configuration.
+   */
+  function testImport() {
+    $name = 'config_test.new';
+    $dynamic_name = 'config_test.dynamic.new';
+
+    // Verify the configuration to create does not exist yet.
+    $file_storage = new FileStorage();
+    $this->assertIdentical($file_storage->exists($name), FALSE, $name . ' not found.');
+    $this->assertIdentical($file_storage->exists($dynamic_name), FALSE, $dynamic_name . ' not found.');
+
+    // Verify that the import UI does not allow to import without exported
+    // configuration.
+    $this->drupalGet('admin/config/development/sync');
+    $this->assertText('There is no base configuration.');
+
+    // Verify that the Export link yields to the export UI page, and export.
+    $this->clickLink('Export');
+    $this->drupalPost(NULL, array(), t('Export'));
+
+    // Create new configuration objects.
+    $file_storage->write($name, array(
+      'add_me' => 'new value',
+    ));
+    $file_storage->write($dynamic_name, array(
+      'id' => 'new',
+      'label' => 'New',
+    ));
+    $this->assertIdentical($file_storage->exists($name), TRUE, $name . ' found.');
+    $this->assertIdentical($file_storage->exists($dynamic_name), TRUE, $dynamic_name . ' found.');
+
+    // Verify that both appear as new.
+    $this->drupalGet('admin/config/development/sync');
+    $this->assertText($name);
+    $this->assertText($dynamic_name);
+
+    // Import and verify that both do not appear anymore.
+    $this->drupalPost(NULL, array(), t('Import'));
+    $this->assertUrl('admin/config/development/sync');
+    $this->assertNoText($name);
+    $this->assertNoText($dynamic_name);
+
+    // Verify that there are no further changes to import.
+    $this->assertText(t('There are no configuration changes.'));
+
+    // Verify that the export screen shows no changes either.
+    $this->drupalGet('admin/config/development/sync/export');
+    $this->assertText(t('There are no configuration changes.'));
+  }
+
+  /**
+   * Tests concurrent importing of configuration.
+   */
+  function testImportLock() {
+    $name = 'config_test.new';
+
+    // Write a configuration object to import.
+    $file_storage = new FileStorage();
+    $file_storage->write($name, array(
+      'add_me' => 'new value',
+    ));
+
+    // Verify that there are configuration differences to import.
+    $this->drupalGet('admin/config/development/sync');
+    $this->assertNoText(t('There are no configuration changes.'));
+
+    // Acquire a fake-lock on the import mechanism.
+    $lock_name = 'config_import';
+    lock_acquire($lock_name);
+
+    // Attempt to import configuration and verify that an error message appears.
+    $this->drupalPost(NULL, array(), t('Import'));
+    $this->assertUrl('admin/config/development/sync');
+    $this->assertText(t('The import failed due to an error. Any errors have been logged.'));
+
+    // Release the lock, just to keep testing sane.
+    lock_release($lock_name);
+  }
+}
diff --git a/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php b/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php
index 2dbc627..e1d77be 100644
--- a/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php
+++ b/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php
@@ -32,6 +32,9 @@
   function testCRUD() {
     $name = 'config_test.storage';
 
+    // Checking whether a non-existing name exists returns FALSE.
+    $this->assertIdentical($this->storage->exists($name), FALSE);
+
     // Reading a non-existing name returns FALSE.
     $data = $this->storage->read($name);
     $this->assertIdentical($data, FALSE);
@@ -51,9 +54,13 @@ function testCRUD() {
     $data = array('foo' => 'bar');
     $result = $this->storage->write($name, $data);
     $this->assertIdentical($result, TRUE);
+
     $raw_data = $this->read($name);
     $this->assertIdentical($raw_data, $data);
 
+    // Checking whether an existing name exists returns TRUE.
+    $this->assertIdentical($this->storage->exists($name), TRUE);
+
     // Writing the identical data again still returns TRUE.
     $result = $this->storage->write($name, $data);
     $this->assertIdentical($result, TRUE);
diff --git a/core/modules/config/tests/config_test/config/config_test.delete.yml b/core/modules/config/tests/config_test/config/config_test.delete.yml
new file mode 100644
index 0000000..b8ccb67
--- /dev/null
+++ b/core/modules/config/tests/config_test/config/config_test.delete.yml
@@ -0,0 +1 @@
+delete_me: bar
diff --git a/core/modules/search/lib/Drupal/search/Tests/SearchExcerptTest.php b/core/modules/search/lib/Drupal/search/Tests/SearchExcerptTest.php
index b96049e..99fd422 100644
--- a/core/modules/search/lib/Drupal/search/Tests/SearchExcerptTest.php
+++ b/core/modules/search/lib/Drupal/search/Tests/SearchExcerptTest.php
@@ -7,12 +7,14 @@
 
 namespace Drupal\search\Tests;
 
-use Drupal\simpletest\UnitTestBase;
+use Drupal\simpletest\WebTestBase;
 
 /**
  * Tests the search_excerpt() function.
  */
-class SearchExcerptTest extends UnitTestBase {
+class SearchExcerptTest extends WebTestBase {
+  public static $modules = array('search');
+
   public static function getInfo() {
     return array(
       'name' => 'Search excerpt extraction',
@@ -21,11 +23,6 @@ public static function getInfo() {
     );
   }
 
-  function setUp() {
-    drupal_load('module', 'search');
-    parent::setUp();
-  }
-
   /**
    * Tests search_excerpt() with several simulated search keywords.
    *
diff --git a/core/profiles/standard/standard.info b/core/profiles/standard/standard.info
index 8b8a33b..c5240dd 100644
--- a/core/profiles/standard/standard.info
+++ b/core/profiles/standard/standard.info
@@ -6,6 +6,7 @@ dependencies[] = node
 dependencies[] = block
 dependencies[] = color
 dependencies[] = comment
+dependencies[] = config
 dependencies[] = contextual
 dependencies[] = help
 dependencies[] = image