diff --git a/meddfnhtst.rpgle b/meddfnhtst.rpgle
index 149fabd..7f02a9a 100644
--- a/meddfnhtst.rpgle
+++ b/meddfnhtst.rpgle
@@ -4,7 +4,10 @@
 //
 // Program......: MEDDFNHTST
 //
-// Description..: MEDDFN Hardware Test Program
+// Description..: MEDDFN hardware test program
+//
+//                Creates one media definition for six parallel streams
+//                using the same tape library device and six media files.
 //
 // Erstellen mit:
 //
@@ -38,38 +41,19 @@ ctl-opt
 
 dcl-pi *n;
 
-   pMediaDef
-      char(10) const;
+   pMediaDefinitionName char(10) const;
+   pLibraryName         char(10) const;
+   pDeviceName          char(10) const;
 
-   pLibrary
-      char(10) const;
+   pVolume1             char(6) const;
+   pVolume2             char(6) const;
+   pVolume3             char(6) const;
+   pVolume4             char(6) const;
+   pVolume5             char(6) const;
+   pVolume6             char(6) const;
 
-   pDevice
-      char(10) const;
-
-   pVolume1
-      char(6) const;
-
-   pVolume2
-      char(6) const;
-
-   pVolume3
-      char(6) const;
-
-   pVolume4
-      char(6) const;
-
-   pVolume5
-      char(6) const;
-
-   pVolume6
-      char(6) const;
-
-   pText
-      char(50) const;
-
-   pReplace
-      char(4) const;
+   pTextDescription     char(50) const;
+   pReplace             char(4) const;
 
 end-pi;
 
@@ -96,19 +80,16 @@ dcl-ds Error
 clear MediaDefinition;
 
 MediaDefinition.MediaDefinitionName =
-   pMediaDef;
+   pMediaDefinitionName;
 
 MediaDefinition.LibraryName =
-   pLibrary;
+   pLibraryName;
 
 MediaDefinition.TextDescription =
-   pText;
+   pTextDescription;
 
-MediaDefinition.MaximumParallelResources =
-   1;
-
-MediaDefinition.MinimumParallelResources =
-   1;
+MediaDefinition.Replace =
+   (pReplace = '*YES');
 
 MediaDefinition.DeviceAllocation =
    MD_DeviceAllocateAll;
@@ -116,128 +97,94 @@ MediaDefinition.DeviceAllocation =
 MediaDefinition.SaveFormat =
    MD_SaveFormatParallel;
 
+MediaDefinition.MaximumParallelResources =
+   6;
+
+MediaDefinition.MinimumParallelResources =
+   6;
+
 MediaDefinition.NumberOfDevices =
-   1;
+   6;
 
 
 //=====================================================================
-//
-// Device
-//
+// Devices and media files
 //=====================================================================
 
-MediaDefinition.Device(1).DeviceName =
-   pDevice;
+MediaDefinition.Device(1).DeviceName = pDeviceName;
+MediaDefinition.Device(2).DeviceName = pDeviceName;
+MediaDefinition.Device(3).DeviceName = pDeviceName;
+MediaDefinition.Device(4).DeviceName = pDeviceName;
+MediaDefinition.Device(5).DeviceName = pDeviceName;
+MediaDefinition.Device(6).DeviceName = pDeviceName;
 
-MediaDefinition.Device(1).NumberOfMediaFiles =
-   1;
+MediaDefinition.Device(1).NumberOfMediaFiles = 1;
+MediaDefinition.Device(2).NumberOfMediaFiles = 1;
+MediaDefinition.Device(3).NumberOfMediaFiles = 1;
+MediaDefinition.Device(4).NumberOfMediaFiles = 1;
+MediaDefinition.Device(5).NumberOfMediaFiles = 1;
+MediaDefinition.Device(6).NumberOfMediaFiles = 1;
 
 
 //=====================================================================
-//
-// Media File
-//
+// Media files
 //=====================================================================
 
-MediaDefinition.Device(1)
-   .MediaFile(1)
-   .SequenceNumber =
-      1;
+MediaDefinition.Device(1).MediaFile(1).SequenceNumber = 1;
+MediaDefinition.Device(2).MediaFile(1).SequenceNumber = 1;
+MediaDefinition.Device(3).MediaFile(1).SequenceNumber = 1;
+MediaDefinition.Device(4).MediaFile(1).SequenceNumber = 1;
+MediaDefinition.Device(5).MediaFile(1).SequenceNumber = 1;
+MediaDefinition.Device(6).MediaFile(1).SequenceNumber = 1;
 
-MediaDefinition.Device(1)
-   .MediaFile(1)
-   .StartingPositionInFile =
-      *ALL'0';
+MediaDefinition.Device(1).MediaFile(1).StartingPositionInFile = *ALL'0';
+MediaDefinition.Device(2).MediaFile(1).StartingPositionInFile = *ALL'0';
+MediaDefinition.Device(3).MediaFile(1).StartingPositionInFile = *ALL'0';
+MediaDefinition.Device(4).MediaFile(1).StartingPositionInFile = *ALL'0';
+MediaDefinition.Device(5).MediaFile(1).StartingPositionInFile = *ALL'0';
+MediaDefinition.Device(6).MediaFile(1).StartingPositionInFile = *ALL'0';
 
-MediaDefinition.Device(1)
-   .MediaFile(1)
-   .NumberOfVolumeIdentifiers =
-      6;
+MediaDefinition.Device(1).MediaFile(1).NumberOfVolumeIdentifiers = 1;
+MediaDefinition.Device(2).MediaFile(1).NumberOfVolumeIdentifiers = 1;
+MediaDefinition.Device(3).MediaFile(1).NumberOfVolumeIdentifiers = 1;
+MediaDefinition.Device(4).MediaFile(1).NumberOfVolumeIdentifiers = 1;
+MediaDefinition.Device(5).MediaFile(1).NumberOfVolumeIdentifiers = 1;
+MediaDefinition.Device(6).MediaFile(1).NumberOfVolumeIdentifiers = 1;
 
 
 //=====================================================================
-//
-// Volume Identifiers
-//
+// Volume identifiers
 //=====================================================================
 
-MediaDefinition.Device(1)
-   .MediaFile(1)
-   .VolumeIdentifier(1)
-   .VolumeIdentifier =
-      pVolume1;
-
-MediaDefinition.Device(1)
-   .MediaFile(1)
-   .VolumeIdentifier(2)
-   .VolumeIdentifier =
-      pVolume2;
-
-MediaDefinition.Device(1)
-   .MediaFile(1)
-   .VolumeIdentifier(3)
-   .VolumeIdentifier =
-      pVolume3;
-
-MediaDefinition.Device(1)
-   .MediaFile(1)
-   .VolumeIdentifier(4)
-   .VolumeIdentifier =
-      pVolume4;
-
-MediaDefinition.Device(1)
-   .MediaFile(1)
-   .VolumeIdentifier(5)
-   .VolumeIdentifier =
-      pVolume5;
-
-MediaDefinition.Device(1)
-   .MediaFile(1)
-   .VolumeIdentifier(6)
-   .VolumeIdentifier =
-      pVolume6;
+MediaDefinition.Device(1).MediaFile(1).VolumeIdentifier(1).VolumeIdentifier = pVolume1;
+MediaDefinition.Device(2).MediaFile(1).VolumeIdentifier(1).VolumeIdentifier = pVolume2;
+MediaDefinition.Device(3).MediaFile(1).VolumeIdentifier(1).VolumeIdentifier = pVolume3;
+MediaDefinition.Device(4).MediaFile(1).VolumeIdentifier(1).VolumeIdentifier = pVolume4;
+MediaDefinition.Device(5).MediaFile(1).VolumeIdentifier(1).VolumeIdentifier = pVolume5;
+MediaDefinition.Device(6).MediaFile(1).VolumeIdentifier(1).VolumeIdentifier = pVolume6;
 
 
 //=====================================================================
-//
-// Replace
-//
-//=====================================================================
-
-MediaDefinition.Replace =
-   (pReplace = '*YES');
-
-
-//=====================================================================
-//
-// Create media definition
-//
+// Create MEDDFN
 //=====================================================================
 
 clear Error;
 
-dsply 'MEDDFNHTST START';
-
 MD_CreateMediaDefinition(
    MediaDefinition :
    Error);
 
-
 if Error.HasError;
 
-   dsply ('ERROR ' + Error.MessageID);
+   dsply ('MEDDFN creation failed: ' +
+          Error.MessageID);
+
+   dsply Error.MessageData;
 
 else;
 
-   dsply 'MEDDFN CREATE OK';
+   dsply 'MEDDFN created successfully';
 
 endif;
 
-//=====================================================================
-//
-// End
-//
-//=====================================================================
-
-*inlr = *on;
-return;
\ No newline at end of file
+return;