Index: trunk/FACT++/src/DataCalib.h
===================================================================
--- trunk/FACT++/src/DataCalib.h	(revision 12618)
+++ trunk/FACT++/src/DataCalib.h	(revision 12619)
@@ -25,4 +25,6 @@
     void WriteFits();
 
+    bool IsDrsCalib() const { return true; }
+
 public:
     DataCalib(const std::string &path, uint32_t id, DimDescribedService &dim, MessageImp &imp) : DataWriteFits(path, id, imp), fDim(dim)
Index: trunk/FACT++/src/DataWriteFits.cc
===================================================================
--- trunk/FACT++/src/DataWriteFits.cc	(revision 12618)
+++ trunk/FACT++/src/DataWriteFits.cc	(revision 12619)
@@ -171,4 +171,7 @@
         // FIXME: I cannot write a double! WHY?
         fFile.WriteKey("REFCLK", avg/cnt*2.048, "Average reference clock frequency in Hz");
+
+        fFile.WriteKey("DRSCALIB", IsDrsCalib(), "This file belongs to a DRS calibration");
+
     }
     catch (const CCfits::FitsException &e)
Index: trunk/FACT++/src/DataWriteFits.h
===================================================================
--- trunk/FACT++/src/DataWriteFits.h	(revision 12618)
+++ trunk/FACT++/src/DataWriteFits.h	(revision 12619)
@@ -25,4 +25,6 @@
     bool WriteFooter(RUN_TAIL *rt);
 
+    virtual bool IsDrsCalib() const { return false; }
+
 public:
     DataWriteFits(const std::string path, uint32_t runid, MessageImp &imp) :