Index: trunk/MagicSoft/Mars/mbase/MLog.cc
===================================================================
--- trunk/MagicSoft/Mars/mbase/MLog.cc	(revision 1862)
+++ trunk/MagicSoft/Mars/mbase/MLog.cc	(revision 1863)
@@ -39,4 +39,36 @@
 // of one eventloop to where you want..                                     //
 //                                                                          //
+// The MLog stream has the advantage, that it can be used like the common   //
+// C++ streams (for example cout). It can redirect the stream to different  //
+// outputs (console, file, GUI) if necessary at the same time.              //
+//                                                                          //
+// It supports different debug levels. The debug level of the current       //
+// stream contents is set by SetDebugLevel, the output level of the         //
+// current stream can be set by SetOutputLevel.                             //
+//                                                                          //
+// The header file MLogManip.h contains so called manipulators (like flush  //
+// or setw from iomanip.h) which can manipulate these levels from within    //
+// stream, for example:                                                     //
+//    gLog << debug(3) << "Hallo World " << endl;                           //
+// sets the debug level of the following stream to 3                        //
+//                                                                          //
+// edev(), ddev() can be used to enable/disable an output device from       //
+// within the stream. The enumerations are defined in MLog::_flags          //
+//                                                                          //
+// Commonly used abbreviations are also defined:                            //
+//    dbginf  Prints source file name and line number. Used for output      //
+//            which people may like to look up in the code                  //
+//    all     Is streamed to the output in any case. Used for outputs       //
+//            which are requested by the user (eg TObject::Print)           //
+//    err     Should be used for fatal errors which stops the current       //
+//            processing, eg:                                               //
+//              gLog << err << "ERROR: TObject::Copy - Stopped" << endl;    //
+//    warn    Warning means an error occured, but it is not clear whether   //
+//            this results further procesing or not.                        //
+//    inf     Informs the user about what's going on. Mostly usefull for    //
+//            debugging, but in general not necessary at all.               //
+//                                                                          //
+// gLog is a global stream defined like cout or cerr                        //
+//                                                                          //
 //////////////////////////////////////////////////////////////////////////////
 
Index: trunk/MagicSoft/Mars/mfilter/MF.cc
===================================================================
--- trunk/MagicSoft/Mars/mfilter/MF.cc	(revision 1862)
+++ trunk/MagicSoft/Mars/mfilter/MF.cc	(revision 1863)
@@ -69,4 +69,9 @@
 //
 //
+//  If you intend to use Data Chains in filters enclose the chains in
+//  this {}-parenthesis, eg.
+//
+//   "{MHillas.fSize*MHillas.fWidth}<0.5"
+//
 // FIXME: The possibility to use also complete filters is missing.
 //        Maybe we can use gInterpreter->Calc("") for this.