diff --git a/Event/ByteStreamCnvSvcLegacy/ByteStreamCnvSvcLegacy/offline_EventStorage/v5_DataWriter.h b/Event/ByteStreamCnvSvcLegacy/ByteStreamCnvSvcLegacy/offline_EventStorage/v5_DataWriter.h
index 0d11bd1199cbfb093892309431a9f5ddabd875f7..a2224310305021995d74152e3a3991918c2987cb 100644
--- a/Event/ByteStreamCnvSvcLegacy/ByteStreamCnvSvcLegacy/offline_EventStorage/v5_DataWriter.h
+++ b/Event/ByteStreamCnvSvcLegacy/ByteStreamCnvSvcLegacy/offline_EventStorage/v5_DataWriter.h
@@ -56,39 +56,39 @@ public:
       \param compression Compression type
       \param compLevel   Compression level
    */
-  DataWriter(const std::string writingPath,     
-	     const std::string fileNameCore,    
-	     const run_parameters_record rPar, 
-	     const std::vector<std::string> fmdStrings, 
+  DataWriter(const std::string& writingPath,     
+	     const std::string& fileNameCore,    
+	     const run_parameters_record& rPar, 
+	     const std::vector<std::string>& fmdStrings, 
 	     const unsigned int startIndex = 1,
 	     const CompressionType compression = NONE,
 	     const unsigned int compLevel = 1); 
 
 
 
-  DataWriter(const std::string writingPath,   
+  DataWriter(const std::string& writingPath,   
 	     boost::shared_ptr<EventStorage::FileNameCallback> theFNCB,
-	     const run_parameters_record rPar, 
-	     const std::string project,
-	     const std::string streamType,
-	     const std::string streamName,
-	     const std::string stream,
+	     const run_parameters_record& rPar, 
+	     const std::string& project,
+	     const std::string& streamType,
+	     const std::string& streamName,
+	     const std::string& stream,
 	     const unsigned int lumiBlockNumber,
-	     const std::string applicationName,
-	     const std::vector<std::string> fmdStrings,
+	     const std::string& applicationName,
+	     const std::vector<std::string>& fmdStrings,
 	     const CompressionType compression = NONE,
 	     const unsigned int compLevel = 1);
 
-  DataWriter(const std::string writingPath,   
-	     const std::string fileNameCore,     
-	     const run_parameters_record rPar, 
-	     const std::string project,
-	     const std::string streamType,
-	     const std::string streamName,
-	     const std::string stream,
+  DataWriter(const std::string& writingPath,   
+	     const std::string& fileNameCore,     
+	     const run_parameters_record& rPar, 
+	     const std::string& project,
+	     const std::string& streamType,
+	     const std::string& streamName,
+	     const std::string& stream,
 	     const unsigned int lumiBlockNumber,
-	     const std::string applicationName,
-	     const std::vector<std::string> fmdStrings,
+	     const std::string& applicationName,
+	     const std::vector<std::string>& fmdStrings,
 	     const CompressionType compression = NONE,
 	     const unsigned int compLevel = 1);
 
@@ -97,16 +97,16 @@ private:
   DataWriter();
 
 
-  void initDW(const std::string writingPath,   
+  void initDW(const std::string& writingPath,   
 	      boost::shared_ptr<EventStorage::FileNameCallback> theFNCB,
-	      const run_parameters_record rPar, 
-	      const std::string project,
-	      const std::string streamType,
-	      const std::string streamName,
-	      const std::string stream,
+	      const run_parameters_record& rPar, 
+	      const std::string& project,
+	      const std::string& streamType,
+	      const std::string& streamName,
+	      const std::string& stream,
 	      const unsigned int lumiBlockNumber,
-	      const std::string applicationName,
-	      const std::vector<std::string> fmdStrings,
+	      const std::string& applicationName,
+	      const std::vector<std::string>& fmdStrings,
 	      const CompressionType compression,
 	      const unsigned int compLevel);
 
diff --git a/Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_DataBuffer.cxx b/Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_DataBuffer.cxx
index 7ca884a85faec7f6aba65da183168cfdd5a7c9ea..371f8bec8dd727e65ece24ad5c8ff2a736ba60d8 100644
--- a/Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_DataBuffer.cxx
+++ b/Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_DataBuffer.cxx
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 
@@ -21,6 +21,9 @@ public:
     m_buffer = new char[size];
     m_buffersize = size;
   }
+
+  implementation (const implementation&) = delete;
+  implementation& operator= (const implementation&) = delete;
  
   ~implementation()
   { delete[] m_buffer; }
diff --git a/Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_DataWriter.cxx b/Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_DataWriter.cxx
index 7fbbf10362e668adc55fc4f74700a6da4f8368d1..3599b5dfffc963f3075c3d506585c070b0b0525a 100644
--- a/Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_DataWriter.cxx
+++ b/Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_DataWriter.cxx
@@ -32,16 +32,16 @@ using EventStorage::SimpleFileName;
 
 // constructors
 DataWriter::
-DataWriter(const string writingPath,   
+DataWriter(const string& writingPath,   
 	   boost::shared_ptr<FileNameCallback> theFNCB,   
-	   const run_parameters_record rPar, 
-	   const std::string project,
-	   const std::string streamType,
-	   const std::string streamName,
-	   const std::string stream,
+	   const run_parameters_record& rPar, 
+	   const std::string& project,
+	   const std::string& streamType,
+	   const std::string& streamName,
+	   const std::string& stream,
 	   const unsigned int lumiBlockNumber,
-	   const std::string applicationName,
-	   const std::vector<std::string> fmdStrings,
+	   const std::string& applicationName,
+	   const std::vector<std::string>& fmdStrings,
 	   const CompressionType compression,
 	   const unsigned int compLevel) 
 {
@@ -50,10 +50,10 @@ DataWriter(const string writingPath,
 }
 
 DataWriter::
-DataWriter(const string writingPath,   
-	   const string fileNameCore,     
-	   const run_parameters_record rPar, 
-	   const freeMetaDataStrings fmdStrings, 
+DataWriter(const string& writingPath,   
+	   const string& fileNameCore,     
+	   const run_parameters_record& rPar, 
+	   const freeMetaDataStrings& fmdStrings, 
 	   const unsigned int startIndex,
 	   const CompressionType compression,
 	   const unsigned int compLevel)
@@ -95,16 +95,16 @@ DataWriter(const string writingPath,
 
 
 DataWriter::
-DataWriter(const string writingPath,   
-	   const string fileNameCore,     
-	   const run_parameters_record rPar, 
-	   const std::string project,
-	   const std::string streamType,
-	   const std::string streamName,
-	   const std::string stream,
+DataWriter(const string& writingPath,   
+	   const string& fileNameCore,     
+	   const run_parameters_record& rPar, 
+	   const std::string& project,
+	   const std::string& streamType,
+	   const std::string& streamName,
+	   const std::string& stream,
 	   const unsigned int lumiBlockNumber,
-	   const std::string applicationName,
-	   const std::vector<std::string> fmdStrings,
+	   const std::string& applicationName,
+	   const std::vector<std::string>& fmdStrings,
 	   const CompressionType compression,
 	   const unsigned int compLevel)
 {
@@ -128,16 +128,16 @@ DataWriter::~DataWriter()
 
 
 void DataWriter::
-initDW(const string writingPath,   
+initDW(const string& writingPath,   
        boost::shared_ptr<FileNameCallback> theFNCB,   
-       const run_parameters_record rPar, 
-       const std::string project,
-       const std::string streamType,
-       const std::string streamName,
-       const std::string stream,
+       const run_parameters_record& rPar, 
+       const std::string& project,
+       const std::string& streamType,
+       const std::string& streamName,
+       const std::string& stream,
        const unsigned int lumiBlockNumber,
-       const std::string applicationName,
-       const std::vector<std::string> fmdStrings,
+       const std::string& applicationName,
+       const std::vector<std::string>& fmdStrings,
        const CompressionType compression,
        const unsigned int compLevel)
 {
diff --git a/Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_Guid.h b/Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_Guid.h
index 9a97b32fcc72774cd6681ebabc6e6533c9cd88ec..cecf5214ead3d25c5ad96823f7f734eff4017524 100644
--- a/Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_Guid.h
+++ b/Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_Guid.h
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 // This is a warapper class for uuid.
@@ -53,10 +53,9 @@ namespace offline_poolCopy_v5  {
         Data1 = g.Data1;
         Data2 = g.Data2;
         Data3 = g.Data3;
-        unsigned int       *p = (unsigned int*)&Data4[0]; 
-        const unsigned int *q = (const unsigned int*)&g.Data4[0];
-        *(p+1) = *(q+1);
-        *p     = *q;
+        for (size_t i = 0; i < 8; i++) {
+          Data4[i] = g.Data4[i];
+        }
       }
       return *this;
     }