diff --git a/src/OSD/OSD_CachedFileSystem.cxx b/src/OSD/OSD_CachedFileSystem.cxx
index e7c119a784..123e54ec85 100644
--- a/src/OSD/OSD_CachedFileSystem.cxx
+++ b/src/OSD/OSD_CachedFileSystem.cxx
@@ -16,13 +16,23 @@
 
 IMPLEMENT_STANDARD_RTTIEXT(OSD_CachedFileSystem, OSD_FileSystem)
 
+//=======================================================================
+// function : OSD_CachedFileSystem
+// purpose :
+//=======================================================================
+OSD_CachedFileSystem::OSD_CachedFileSystem (const Handle(OSD_FileSystem)& theLinkedFileSystem)
+: myLinkedFS (!theLinkedFileSystem.IsNull() ? theLinkedFileSystem : OSD_FileSystem::DefaultFileSystem())
+{
+  //
+}
+
 //=======================================================================
 // function : IsSupportedPath
 // purpose :
 //=======================================================================
 Standard_Boolean OSD_CachedFileSystem::IsSupportedPath (const TCollection_AsciiString& theUrl) const
 {
-  return OSD_FileSystem::DefaultFileSystem()->IsSupportedPath (theUrl);
+  return myLinkedFS->IsSupportedPath (theUrl);
 }
 
 //=======================================================================
@@ -31,7 +41,7 @@ Standard_Boolean OSD_CachedFileSystem::IsSupportedPath (const TCollection_AsciiS
 //=======================================================================
 Standard_Boolean OSD_CachedFileSystem::IsOpenIStream (const opencascade::std::shared_ptr<std::istream>& theStream) const
 {
-  return OSD_FileSystem::DefaultFileSystem()->IsOpenIStream (theStream);
+  return myLinkedFS->IsOpenIStream (theStream);
 }
 
 //=======================================================================
@@ -40,7 +50,7 @@ Standard_Boolean OSD_CachedFileSystem::IsOpenIStream (const opencascade::std::sh
 //=======================================================================
 Standard_Boolean OSD_CachedFileSystem::IsOpenOStream (const opencascade::std::shared_ptr<std::ostream>& theStream) const
 {
-  return OSD_FileSystem::DefaultFileSystem()->IsOpenOStream (theStream);
+  return myLinkedFS->IsOpenOStream (theStream);
 }
 
 //=======================================================================
@@ -57,7 +67,7 @@ opencascade::std::shared_ptr<std::istream> OSD_CachedFileSystem::OpenIStream (co
     myStream.Url = theUrl;
     myStream.Reset();
   }
-  myStream.Stream = OSD_FileSystem::DefaultFileSystem()->OpenIStream (theUrl, theParams, theOffset, myStream.Stream);
+  myStream.Stream = myLinkedFS->OpenIStream (theUrl, theParams, theOffset, myStream.Stream);
   return myStream.Stream;
 }
 
@@ -68,7 +78,7 @@ opencascade::std::shared_ptr<std::istream> OSD_CachedFileSystem::OpenIStream (co
 opencascade::std::shared_ptr<std::ostream> OSD_CachedFileSystem::OpenOStream (const TCollection_AsciiString& theUrl,
                                                                               const std::ios_base::openmode theMode)
 {
-  return OSD_FileSystem::DefaultFileSystem()->OpenOStream (theUrl, theMode);
+  return myLinkedFS->OpenOStream (theUrl, theMode);
 }
 
 //=======================================================================
@@ -82,13 +92,13 @@ opencascade::std::shared_ptr<std::streambuf> OSD_CachedFileSystem::OpenStreamBuf
 {
   if ((theMode & std::ios::out) == std::ios::out)
   {
-    return OSD_FileSystem::DefaultFileSystem()->OpenStreamBuffer (theUrl, theMode, theOffset, theOutBufSize);
+    return myLinkedFS->OpenStreamBuffer (theUrl, theMode, theOffset, theOutBufSize);
   }
   if (myStream.Url != theUrl)
   {
     myStream.Url = theUrl;
     myStream.Reset();
   }
-  myStream.StreamBuf = OSD_FileSystem::DefaultFileSystem()->OpenStreamBuffer (theUrl, theMode, theOffset, theOutBufSize);
+  myStream.StreamBuf = myLinkedFS->OpenStreamBuffer (theUrl, theMode, theOffset, theOutBufSize);
   return myStream.StreamBuf;
 }
diff --git a/src/OSD/OSD_CachedFileSystem.hxx b/src/OSD/OSD_CachedFileSystem.hxx
index b7389ec890..170edcf7a9 100644
--- a/src/OSD/OSD_CachedFileSystem.hxx
+++ b/src/OSD/OSD_CachedFileSystem.hxx
@@ -16,7 +16,7 @@
 
 #include <OSD_FileSystem.hxx>
 
-//! File system keeping last stream created by OSD_FileSystem::DefaultFileSystem() to be reused for opening a stream with the same URL.
+//! File system keeping last stream created by linked file system (OSD_FileSystem::DefaultFileSystem() by default) to be reused for opening a stream with the same URL.
 //! Note that as file is kept in opened state, application will need destroying this object to ensure all files being closed.
 //! This interface could be handy in context of reading numerous objects pointing to the same file (at different offset).
 //! Make sure to create a dedicated OSD_CachedFileSystem for each working thread to avoid data races.
@@ -26,7 +26,13 @@ class OSD_CachedFileSystem : public OSD_FileSystem
 public:
 
   //! Constructor.
-  OSD_CachedFileSystem() {}
+  Standard_EXPORT OSD_CachedFileSystem (const Handle(OSD_FileSystem)& theLinkedFileSystem = Handle(OSD_FileSystem)());
+
+  //! Return linked file system; initialized with OSD_FileSystem::DefaultFileSystem() by default.
+  const Handle(OSD_FileSystem)& LinkedFileSystem() const { return myLinkedFS; }
+
+  //! Sets linked file system.
+  void SetLinkedFileSystem (const Handle(OSD_FileSystem)& theLinkedFileSystem) { myLinkedFS = theLinkedFileSystem; }
 
   //! Returns TRUE if URL defines a supported protocol.
   Standard_EXPORT virtual Standard_Boolean IsSupportedPath (const TCollection_AsciiString& theUrl) const Standard_OVERRIDE;
@@ -73,7 +79,8 @@ protected:
 
 protected:
 
-  OSD_CachedStream myStream;
+  OSD_CachedStream       myStream;   //!< active cached stream
+  Handle(OSD_FileSystem) myLinkedFS; //!< linked file system to open files
 
 };