diff --git a/14-checkpoint/Makefile b/14-checkpoint/Makefile
index b6112574..7d43bc30 100644
--- a/14-checkpoint/Makefile
+++ b/14-checkpoint/Makefile
@@ -27,7 +27,7 @@ run: os-image.bin
 
 # Open the connection to qemu and load our kernel-object file with symbols
 debug: os-image.bin kernel.elf
-	qemu-system-i386 -s -fda os-image.bin &
+	qemu-system-i386 -s -S -fda os-image.bin &
 	${GDB} -ex "target remote localhost:1234" -ex "symbol-file kernel.elf"
 
 # Generic rules for wildcards
diff --git a/15-video-ports/Makefile b/15-video-ports/Makefile
index b6112574..7d43bc30 100644
--- a/15-video-ports/Makefile
+++ b/15-video-ports/Makefile
@@ -27,7 +27,7 @@ run: os-image.bin
 
 # Open the connection to qemu and load our kernel-object file with symbols
 debug: os-image.bin kernel.elf
-	qemu-system-i386 -s -fda os-image.bin &
+	qemu-system-i386 -s -S -fda os-image.bin &
 	${GDB} -ex "target remote localhost:1234" -ex "symbol-file kernel.elf"
 
 # Generic rules for wildcards
diff --git a/16-video-driver/Makefile b/16-video-driver/Makefile
index b6112574..7d43bc30 100644
--- a/16-video-driver/Makefile
+++ b/16-video-driver/Makefile
@@ -27,7 +27,7 @@ run: os-image.bin
 
 # Open the connection to qemu and load our kernel-object file with symbols
 debug: os-image.bin kernel.elf
-	qemu-system-i386 -s -fda os-image.bin &
+	qemu-system-i386 -s -S -fda os-image.bin &
 	${GDB} -ex "target remote localhost:1234" -ex "symbol-file kernel.elf"
 
 # Generic rules for wildcards
diff --git a/17-video-scroll/Makefile b/17-video-scroll/Makefile
index b6112574..7d43bc30 100644
--- a/17-video-scroll/Makefile
+++ b/17-video-scroll/Makefile
@@ -27,7 +27,7 @@ run: os-image.bin
 
 # Open the connection to qemu and load our kernel-object file with symbols
 debug: os-image.bin kernel.elf
-	qemu-system-i386 -s -fda os-image.bin &
+	qemu-system-i386 -s -S -fda os-image.bin &
 	${GDB} -ex "target remote localhost:1234" -ex "symbol-file kernel.elf"
 
 # Generic rules for wildcards
diff --git a/18-interrupts/Makefile b/18-interrupts/Makefile
index 8a68aa00..6575ba6f 100644
--- a/18-interrupts/Makefile
+++ b/18-interrupts/Makefile
@@ -27,7 +27,7 @@ run: os-image.bin
 
 # Open the connection to qemu and load our kernel-object file with symbols
 debug: os-image.bin kernel.elf
-	qemu-system-i386 -s -fda os-image.bin -d guest_errors,int &
+	qemu-system-i386 -s -S -fda os-image.bin -d guest_errors,int &
 	${GDB} -ex "target remote localhost:1234" -ex "symbol-file kernel.elf"
 
 # Generic rules for wildcards
diff --git a/18-interrupts/cpu/idt.c b/18-interrupts/cpu/idt.c
index 999d0c94..cdb7e99b 100644
--- a/18-interrupts/cpu/idt.c
+++ b/18-interrupts/cpu/idt.c
@@ -1,6 +1,9 @@
 #include "idt.h"
 #include "../kernel/util.h"
 
+idt_gate_t idt[IDT_ENTRIES];
+idt_register_t idt_reg;
+
 void set_idt_gate(int n, u32 handler) {
     idt[n].low_offset = low_16(handler);
     idt[n].sel = KERNEL_CS;
diff --git a/18-interrupts/cpu/idt.h b/18-interrupts/cpu/idt.h
index 27bfac5a..b31f3e31 100644
--- a/18-interrupts/cpu/idt.h
+++ b/18-interrupts/cpu/idt.h
@@ -28,8 +28,6 @@ typedef struct {
 } __attribute__((packed)) idt_register_t;
 
 #define IDT_ENTRIES 256
-idt_gate_t idt[IDT_ENTRIES];
-idt_register_t idt_reg;
 
 
 /* Functions implemented in idt.c */
diff --git a/19-interrupts-irqs/Makefile b/19-interrupts-irqs/Makefile
index 8a68aa00..6575ba6f 100644
--- a/19-interrupts-irqs/Makefile
+++ b/19-interrupts-irqs/Makefile
@@ -27,7 +27,7 @@ run: os-image.bin
 
 # Open the connection to qemu and load our kernel-object file with symbols
 debug: os-image.bin kernel.elf
-	qemu-system-i386 -s -fda os-image.bin -d guest_errors,int &
+	qemu-system-i386 -s -S -fda os-image.bin -d guest_errors,int &
 	${GDB} -ex "target remote localhost:1234" -ex "symbol-file kernel.elf"
 
 # Generic rules for wildcards
diff --git a/20-interrupts-timer/Makefile b/20-interrupts-timer/Makefile
index 4d6da943..c80e4eda 100644
--- a/20-interrupts-timer/Makefile
+++ b/20-interrupts-timer/Makefile
@@ -27,7 +27,7 @@ run: os-image.bin
 
 # Open the connection to qemu and load our kernel-object file with symbols
 debug: os-image.bin kernel.elf
-	qemu-system-i386 -s -fda os-image.bin -d guest_errors,int &
+	qemu-system-i386 -s -S -fda os-image.bin -d guest_errors,int &
 	${GDB} -ex "target remote localhost:1234" -ex "symbol-file kernel.elf"
 
 # Generic rules for wildcards
diff --git a/21-shell/Makefile b/21-shell/Makefile
index 14782944..8a89a506 100644
--- a/21-shell/Makefile
+++ b/21-shell/Makefile
@@ -28,7 +28,7 @@ run: os-image.bin
 
 # Open the connection to qemu and load our kernel-object file with symbols
 debug: os-image.bin kernel.elf
-	qemu-system-i386 -s -fda os-image.bin -d guest_errors,int &
+	qemu-system-i386 -s -S -fda os-image.bin -d guest_errors,int &
 	${GDB} -ex "target remote localhost:1234" -ex "symbol-file kernel.elf"
 
 # Generic rules for wildcards
diff --git a/22-malloc/Makefile b/22-malloc/Makefile
index 14782944..8a89a506 100644
--- a/22-malloc/Makefile
+++ b/22-malloc/Makefile
@@ -28,7 +28,7 @@ run: os-image.bin
 
 # Open the connection to qemu and load our kernel-object file with symbols
 debug: os-image.bin kernel.elf
-	qemu-system-i386 -s -fda os-image.bin -d guest_errors,int &
+	qemu-system-i386 -s -S -fda os-image.bin -d guest_errors,int &
 	${GDB} -ex "target remote localhost:1234" -ex "symbol-file kernel.elf"
 
 # Generic rules for wildcards
diff --git a/23-fixes/Makefile b/23-fixes/Makefile
index 65e577be..19ed0884 100644
--- a/23-fixes/Makefile
+++ b/23-fixes/Makefile
@@ -27,7 +27,7 @@ run: os-image.bin
 
 # Open the connection to qemu and load our kernel-object file with symbols
 debug: os-image.bin kernel.elf
-	qemu-system-i386 -s -fda os-image.bin -d guest_errors,int &
+	qemu-system-i386 -s -S -fda os-image.bin -d guest_errors,int &
 	${GDB} -ex "target remote localhost:1234" -ex "symbol-file kernel.elf"
 
 # Generic rules for wildcards