diff --git a/src/core/diskdevice.cpp b/src/core/diskdevice.cpp
index 8922ea1..6a1cdee 100644
--- a/src/core/diskdevice.cpp
+++ b/src/core/diskdevice.cpp
@@ -131,10 +131,10 @@ qint64 DiskDevice::logicalSectorSize() const
 
 qint64 DiskDevice::totalSectors() const
 {
-    return static_cast<qint64>(heads()) * cylinders() * sectorsPerTrack();
+    return static_cast<qint64>(d->m_Heads) * d->m_Cylinders * d->m_SectorsPerTrack;
 }
 
 qint64 DiskDevice::cylinderSize() const
 {
-    return static_cast<qint64>(heads()) * sectorsPerTrack();
+    return static_cast<qint64>(d->m_Heads) * d->m_SectorsPerTrack;
 }
diff --git a/src/core/diskdevice.h b/src/core/diskdevice.h
index f535179..5b5013c 100644
--- a/src/core/diskdevice.h
+++ b/src/core/diskdevice.h
@@ -58,11 +58,13 @@ public:
     /**
      * @return the number of heads on the Device in CHS notation
      */
+    [[deprecated]]
     qint32 heads() const;
 
     /**
      * @return the number of cylinders on the Device in CHS notation
      */
+    [[deprecated]]
     qint32 cylinders() const;
 
     /**