diff --git a/c_os/devices/CGA_Stream.h b/c_os/devices/CGA_Stream.h
index faebb28..21b7264 100755
--- a/c_os/devices/CGA_Stream.h
+++ b/c_os/devices/CGA_Stream.h
@@ -58,6 +58,8 @@ public:
         pos = 0;
     }
 
+    // CAn't make singleton because atexit
+
 //    ~CGA_Stream() override = default;
 
     void lock() { sem.p(); }
diff --git a/c_os/devices/PCSPK.h b/c_os/devices/PCSPK.h
index d71e220..cf49085 100755
--- a/c_os/devices/PCSPK.h
+++ b/c_os/devices/PCSPK.h
@@ -73,9 +73,11 @@ public:
     // Konstruktor. Initialisieren der Ports.
     PCSPK() = default;
 
+    // Can't make singleton because atexit
+
     // Demo Sounds
-    void tetris();
-    void aerodynamic();
+    static void tetris();
+    static void aerodynamic();
 
     // Ton abspielen
     static void play(float f, int len);
diff --git a/c_os/devices/VESA.h b/c_os/devices/VESA.h
index e0bbebf..4272bf5 100644
--- a/c_os/devices/VESA.h
+++ b/c_os/devices/VESA.h
@@ -32,6 +32,8 @@ public:
 
     VESA() : log("VESA") {}
 
+    // Can't make singleton because atexit
+
     // Bestimmten Grafikmodus einschalten
     bool initGraphicMode(unsigned short mode);
     static void initTextMode();
diff --git a/c_os/kernel/BIOS.h b/c_os/kernel/BIOS.h
index 6d9e4e4..608df36 100644
--- a/c_os/kernel/BIOS.h
+++ b/c_os/kernel/BIOS.h
@@ -34,11 +34,17 @@ struct BIOScall_params {
 extern  BIOScall_params* BC_params;
 
 class BIOS {
+private:
+    // Initialisierung: manuelles Anlegen einer Funktion
+    BIOS();
+
 public:
     BIOS(const BIOS& copy) = delete;  // Verhindere Kopieren
 
-    // Initialisierung: manuelles Anlegen einer Funktion
-    BIOS();
+    static BIOS& instance() {
+        static BIOS bios;
+        return bios;
+    }
 
     // BIOS-Aufruf, per Software-Interrupt
     static void Int(int inter);
diff --git a/c_os/kernel/Globals.cc b/c_os/kernel/Globals.cc
index 68e3de8..9071279 100755
--- a/c_os/kernel/Globals.cc
+++ b/c_os/kernel/Globals.cc
@@ -11,7 +11,7 @@
 #include "kernel/Globals.h"
 
 CGA_Stream kout;  // Ausgabe-Strom fuer Kernel
-BIOS bios;        // Schnittstelle zum 16-Bit BIOS
+const BIOS& bios = BIOS::instance();        // Schnittstelle zum 16-Bit BIOS
 VESA vesa;        // VESA-Treiber
 
 PIC pic;               // Interrupt-Controller
diff --git a/c_os/kernel/Globals.h b/c_os/kernel/Globals.h
index b13374d..77fa40e 100755
--- a/c_os/kernel/Globals.h
+++ b/c_os/kernel/Globals.h
@@ -30,7 +30,7 @@
 // I wanted to make more of these singletons but there were problems with atexit missing because of nostdlib I guess
 
 extern CGA_Stream kout;  // Ausgabe-Strom fuer Kernel
-extern BIOS bios;        // Schnittstelle zum 16-Bit BIOS
+extern const BIOS& bios;        // Schnittstelle zum 16-Bit BIOS
 extern VESA vesa;        // VESA-Treiber
 
 extern PIC pic;               // Interrupt-Controller
diff --git a/c_os/kernel/interrupts/PIC.h b/c_os/kernel/interrupts/PIC.h
index af96c88..9838e5d 100755
--- a/c_os/kernel/interrupts/PIC.h
+++ b/c_os/kernel/interrupts/PIC.h
@@ -29,6 +29,8 @@ public:
 
     PIC() = default;
 
+    // Can't make static because atexit
+
     // IRQ-Nummern von Geraeten
     enum {
         timer = 0,     // Programmable Interrupt Timer (PIT)
diff --git a/c_os/user/demo/PCSPKdemo.cc b/c_os/user/demo/PCSPKdemo.cc
index 6c2eb22..4792008 100644
--- a/c_os/user/demo/PCSPKdemo.cc
+++ b/c_os/user/demo/PCSPKdemo.cc
@@ -6,7 +6,7 @@ void PCSPKdemo::run() {
     kout << "Playing..." << endl;
     kout.unlock();
 
-    (pcspk.*melody)();  // This syntax is confusing as hell
+    (*melody)();  // This syntax is confusing as hell
 
     kout.lock();
     kout << "Finished" << endl;
diff --git a/c_os/user/demo/PCSPKdemo.h b/c_os/user/demo/PCSPKdemo.h
index 9635e00..7c4da26 100644
--- a/c_os/user/demo/PCSPKdemo.h
+++ b/c_os/user/demo/PCSPKdemo.h
@@ -6,12 +6,12 @@
 
 class PCSPKdemo : public Thread {
 private:
-    void (PCSPK::*melody)();  // Allow to pass a melody to play when initializing the demo
+    void (*melody)();  // Allow to pass a melody to play when initializing the demo
 
 public:
     PCSPKdemo(const PCSPKdemo& copy) = delete;
 
-    explicit PCSPKdemo(void (PCSPK::*melody)()) : Thread("PCSPKdemo"), melody(melody) {}
+    PCSPKdemo(void (*melody)()) : Thread("PCSPKdemo"), melody(melody) {}
 
     ~PCSPKdemo() override {
         PCSPK::off();
diff --git a/c_os/user/devices/SerialOut.h b/c_os/user/devices/SerialOut.h
index f71e785..822a296 100644
--- a/c_os/user/devices/SerialOut.h
+++ b/c_os/user/devices/SerialOut.h
@@ -14,8 +14,10 @@ private:
     static int is_transmit_empty();
 
 public:
-    SerialOut(const SerialOut& copy) = delete;
     SerialOut();
+    SerialOut(const SerialOut& copy) = delete;
+
+    // Can't make singleton because atexit
 
     static char read();
     static void write(char a);