diff --git a/filesystem/filesystem-tests.ts b/filesystem/filesystem-tests.ts
new file mode 100644
index 000000000..8f175db98
--- /dev/null
+++ b/filesystem/filesystem-tests.ts
@@ -0,0 +1,49 @@
+/// <reference path="filesystem.d.ts" />
+// http://www.w3.org/TR/file-system-api/
+
+// 2. Introduction
+declare function getAsText(file:File): void;
+declare function writeDataToLogFile(fileWriter:FileWriterSync): void;
+
+function useAsyncFS(fs:FileSystem):void {
+  // see getAsText example in [FILE-API-ED].
+  fs.root.getFile("already_there.txt", null, function (f:FileEntry): void{
+
+    // In the example of the specification, there is a following code:
+    // 
+    //     getAsText(f.file());
+    //
+    // It seems wrong because f is ASYNCRONOUS file system.
+    f.file(getAsText); 
+    
+  });
+
+  // But now we can also write to the file; see [FILE-WRITER-ED].
+  fs.root.getFile("logFile", {create: true}, function (f:FileEntry): void{
+    f.createWriter(writeDataToLogFile);
+  });
+}
+window.requestFileSystem(window.TEMPORARY, 1024 * 1024, function(fs:FileSystem): void{
+  useAsyncFS(fs);
+});
+
+// In a worker:
+
+var tempFS:FileSystemSync = window.requestFileSystemSync(window.TEMPORARY, 1024 * 1024);
+var logFile:FileEntrySync = tempFS.root.getFile("logFile", {create: true});
+var writer:FileWriterSync = logFile.createWriter();
+writer.seek(writer.length);
+writeDataToLogFile(writer);
+
+
+// 5.2 The Flags dictionary
+var fsSync:FileSystemSync = window.requestFileSystemSync(window.TEMPORARY, 1024 * 1024);
+// Get the data directory, creating it if it doesn't exist.
+var dataDir:DirectoryEntrySync = fsSync.root.getDirectory("data", {create: true});
+
+// Create the lock file, if and only if it doesn't exist.
+try {
+  var lockFile:FileEntrySync = dataDir.getFile("lockfile.txt", {create: true, exclusive: true});
+} catch (ex) {
+  // It already exists, or something else went wrong.
+}
diff --git a/filesystem/filesystem.d.ts b/filesystem/filesystem.d.ts
index 69477b13d..444f67a47 100644
--- a/filesystem/filesystem.d.ts
+++ b/filesystem/filesystem.d.ts
@@ -1,6 +1,9 @@
 // Type Definitions for File API: Directories and System (File System API)
-// Specification: http://www.w3.org/TR/file-system-api/
+// Project: http://www.w3.org/TR/file-system-api/
 // Definitions by: Kon <http://phyzkit.net/> 
+// Definitions: https://github.com/borisyankov/DefinitelyTyped 
+
+/// <reference path="filewriter.d.ts" />
 
 interface LocalFileSystem {
     
@@ -8,7 +11,7 @@ interface LocalFileSystem {
      * Used for storage with no guarantee of persistence.
      */
     TEMPORARY:number;
-    
+
     /**
      * Used for storage that should not be removed by the user agent without application or user permission.
      */
@@ -32,7 +35,7 @@ interface LocalFileSystem {
     resolveLocalFileSystemURL(url:string, successCallback:EntryCallback, errorCallback?:ErrorCallback):void;
 
     /**
-     * see resolveLocalFileSystemURL.
+     * see requestFileSystem.
      */
     webkitRequestFileSystem(type:number, size:number, successCallback:FileSystemCallback, errorCallback?:ErrorCallback):void;
 }