diff --git a/kernel/include/acpi.hpp b/kernel/include/acpi.hpp
index 52065d49..0f4257e7 100644
--- a/kernel/include/acpi.hpp
+++ b/kernel/include/acpi.hpp
@@ -10,7 +10,7 @@
 
 namespace acpi {
 
-void init();
+bool init();
 void shutdown();
 
 } //end of acpi namespace
diff --git a/kernel/include/paging.hpp b/kernel/include/paging.hpp
index 88c4c0bd..237f06cf 100644
--- a/kernel/include/paging.hpp
+++ b/kernel/include/paging.hpp
@@ -14,8 +14,11 @@ namespace paging {
 
 const int PAGE_SIZE = 4096;
 
-bool identity_map(void* physical);
-bool identity_map(void* physical, size_t pages);
+void* physical_address(void* virt);
+bool page_present(void* virt);
+bool page_free_or_set(void* virt, void* physical);
+bool identity_map(void* virt);
+bool identity_map(void* virt, size_t pages);
 
 } //end of namespace paging
 
diff --git a/kernel/include/utils.hpp b/kernel/include/utils.hpp
index be348bad..89fd17c4 100644
--- a/kernel/include/utils.hpp
+++ b/kernel/include/utils.hpp
@@ -25,6 +25,8 @@ uint64_t str_len(const char* a);
 const char* str_until(char* a, char c);
 const char* str_from(char* a, char c);
 
+void memset(void * ptr, uint8_t value, size_t num);
+
 template<typename T>
 void memcopy(T* destination, const T* source, size_t size){
     --source;
diff --git a/kernel/src/acpi.cpp b/kernel/src/acpi.cpp
index e1698641..2db06d1a 100644
--- a/kernel/src/acpi.cpp
+++ b/kernel/src/acpi.cpp
@@ -15,37 +15,39 @@
 
 namespace {
 
-uint32_t *SMI_CMD;
+uint32_t SMI_CMD; //ptr
 uint8_t ACPI_ENABLE;
 uint8_t ACPI_DISABLE;
-uint32_t *PM1a_CNT;
-uint32_t *PM1b_CNT;
+uint32_t PM1a_CNT; //ptr
+uint32_t PM1b_CNT; //ptr
 uint16_t SLP_TYPa;
 uint16_t SLP_TYPb;
 uint16_t SLP_EN;
 uint16_t SCI_EN;
 uint8_t PM1_CNT_LEN;
 
+bool version_2 = false;
+
 struct RSDPtr {
    uint8_t Signature[8];
    uint8_t CheckSum;
    uint8_t OemID[6];
    uint8_t Revision;
-   uint32_t *RsdtAddress;
+   uint32_t RsdtAddress; //ptr
 };
 
 struct FACP {
    uint8_t Signature[4];
    uint32_t Length;
    uint8_t unneded1[40 - 8];
-   uint32_t *DSDT;
+   uint32_t DSDT; //ptr
    uint8_t unneded2[48 - 44];
-   uint32_t *SMI_CMD;
+   uint32_t SMI_CMD; //ptr
    uint8_t ACPI_ENABLE;
    uint8_t ACPI_DISABLE;
    uint8_t unneded3[64 - 54];
-   uint32_t *PM1a_CNT_BLK;
-   uint32_t *PM1b_CNT_BLK;
+   uint32_t PM1a_CNT_BLK; //ptr
+   uint32_t PM1b_CNT_BLK; //ptr
    uint8_t unneded4[89 - 72];
    uint8_t PM1_CNT_LEN;
 };
@@ -83,10 +85,8 @@ unsigned int* check_rsd_ptr(unsigned int *ptr) {
 
       // found valid rsdpd
       if (check == 0) {
-          if (rsdp->Revision == 0)
-              k_print_line("ACPI 1");
-         else
-              k_print_line("ACPI 2");
+          version_2 = rsdp->Revision != 0;
+
          return reinterpret_cast<unsigned int *>(rsdp->RsdtAddress);
       }
    }
@@ -142,14 +142,14 @@ int check_header(unsigned int *ptr, const char* sig){
 
 int acpiEnable(void){
     // check if acpi is enabled
-    if ( (in_word(reinterpret_cast<uint64_t>(PM1a_CNT)) &SCI_EN) == 0 ){
+    if ( (in_word(PM1a_CNT) &SCI_EN) == 0 ){
         // check if acpi can be enabled
         if (SMI_CMD != 0 && ACPI_ENABLE != 0){
-            out_byte(reinterpret_cast<uint64_t>(SMI_CMD), ACPI_ENABLE); // send acpi enable command
+            out_byte(SMI_CMD, ACPI_ENABLE); // send acpi enable command
             // give 3 seconds time to enable acpi
             int i;
             for (i=0; i<300; i++ ){
-                if ( (in_word(reinterpret_cast<uint64_t>(PM1a_CNT)) & SCI_EN) == 1 )
+                if ( (in_word(PM1a_CNT) & SCI_EN) == 1 )
                     break;
                 sleep_ms(10);
             }
@@ -157,7 +157,7 @@ int acpiEnable(void){
             if (PM1b_CNT != 0)
                 for (; i<300; i++ )
                 {
-                    if ( (in_word(reinterpret_cast<uint64_t>(PM1b_CNT)) & SCI_EN) == 1 )
+                    if ( (in_word(PM1b_CNT) & SCI_EN) == 1 )
                         break;
                     sleep_ms(10);
                 }
@@ -199,17 +199,12 @@ int acpiEnable(void){
 int init_acpi(){
    unsigned int *ptr = get_rsd_ptr();
 
-   k_printf("%h\n", reinterpret_cast<uintptr_t>(ptr));
-
    if(!paging::identity_map(ptr, 16)){
-       k_print_line("Impossible to map the ACPI tables");
-
        return -1;
    }
 
    // check if address is correct  ( if acpi is available on this pc )
    if (ptr && check_header(ptr, "RSDT") == 0){
-      //k_print_line("2");
       // the RSDT contains an unknown number of pointers to acpi tables
       int entrys = *(ptr + 1);
       entrys = (entrys-36) /4;
@@ -220,11 +215,12 @@ int init_acpi(){
          if (check_header(reinterpret_cast<unsigned int*>(*ptr), "FACP") == 0){
             entrys = -2;
 
-            struct FACP *facp = reinterpret_cast<FACP*>(*ptr);
+            struct FACP* facp = reinterpret_cast<FACP*>(*ptr);
+
             if (check_header(reinterpret_cast<unsigned int*>(facp->DSDT), "DSDT") == 0){
                // search the \_S5 package in the DSDT
                char *S5Addr = reinterpret_cast<char *>(facp->DSDT + 36); // skip header
-               int dsdtLength = *(facp->DSDT+1) -36;
+               int dsdtLength = *(reinterpret_cast<uint32_t*>(static_cast<uintptr_t>(facp->DSDT)+1)) - 36;
                while (0 < dsdtLength--){
                   if ( memcmp(S5Addr, "_S5_", 4) == 0)
                      break;
@@ -287,8 +283,8 @@ int init_acpi(){
 
 } //end of anonymous namespace
 
-void acpi::init(){
-    init_acpi();
+bool acpi::init(){
+    return init_acpi() == 0;
 }
 
 void acpi::shutdown(){
@@ -300,9 +296,9 @@ void acpi::shutdown(){
    acpiEnable();
 
    // send the shutdown command
-   out_word(reinterpret_cast<uint64_t>(PM1a_CNT), SLP_TYPa | SLP_EN );
+   out_word(PM1a_CNT, SLP_TYPa | SLP_EN );
    if ( PM1b_CNT != 0 ){
-      out_word(reinterpret_cast<uint64_t>(PM1b_CNT), SLP_TYPb | SLP_EN );
+      out_word(PM1b_CNT, SLP_TYPb | SLP_EN );
    }
 
    k_print_line("acpi poweroff failed.");
diff --git a/kernel/src/paging.cpp b/kernel/src/paging.cpp
index f39bdfcf..f3dde5e9 100644
--- a/kernel/src/paging.cpp
+++ b/kernel/src/paging.cpp
@@ -7,6 +7,9 @@
 
 #include "paging.hpp"
 #include "types.hpp"
+#include "utils.hpp"
+
+#include "console.hpp"
 
 namespace {
 
@@ -16,44 +19,153 @@ typedef pt_t* pdt_t;
 typedef pdt_t* pdpt_t;
 typedef pdpt_t* pml4t_t;
 
+constexpr int PRESENT = 0x1;
+constexpr int WRITEABLE = 0x2;
+constexpr int USER = 0x4;
+
+//Memory from 0x70000 can be used for pages
+uintptr_t last_page = 0x73000;
+
+uintptr_t init_new_page(){
+    auto new_page = last_page + paging::PAGE_SIZE;
+
+    memset(reinterpret_cast<void*>(new_page), 0, paging::PAGE_SIZE);
+
+    last_page = new_page;
+
+    return new_page;
+}
+
+constexpr bool page_aligned(void* addr){
+    return !(reinterpret_cast<uintptr_t>(addr) & (paging::PAGE_SIZE - 1));
+}
+
 } //end of anonymous namespace
 
-bool paging::identity_map(void* physical){
+void* paging::physical_address(void* virt){
+    if(!page_present(virt)){
+        //TODO Not a very good value since 0x0 is a valid physical address
+        return nullptr;
+    }
+
+    //Find the correct indexes inside the paging table for the physical address
+    auto table = (reinterpret_cast<uintptr_t>(virt) >> 12) & 0x1FF;
+    auto directory = (reinterpret_cast<uintptr_t>(virt) >> 21) & 0x1FF;
+    auto directory_ptr = (reinterpret_cast<uintptr_t>(virt) >> 30) & 0x1FF;
+    auto pml4 = (reinterpret_cast<uintptr_t>(virt) >> 39) & 0x1FF;
+
+    pml4t_t pml4t = reinterpret_cast<pml4t_t>(0x70000);
+
+    auto pdpt = reinterpret_cast<pdpt_t>(reinterpret_cast<uintptr_t>(pml4t[pml4]) & ~0xFFF);
+    auto pdt = reinterpret_cast<pdt_t>(reinterpret_cast<uintptr_t>(pdpt[directory_ptr]) & ~0xFFF);
+    auto pt = reinterpret_cast<pt_t>(reinterpret_cast<uintptr_t>(pdt[directory]) & ~0xFFF);
+    return reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(pt[table]) & ~0xFFF);
+}
+
+bool paging::page_present(void* virt){
+    //Find the correct indexes inside the paging table for the physical address
+    auto table = (reinterpret_cast<uintptr_t>(virt) >> 12) & 0x1FF;
+    auto directory = (reinterpret_cast<uintptr_t>(virt) >> 21) & 0x1FF;
+    auto directory_ptr = (reinterpret_cast<uintptr_t>(virt) >> 30) & 0x1FF;
+    auto pml4 = (reinterpret_cast<uintptr_t>(virt) >> 39) & 0x1FF;
+
+    pml4t_t pml4t = reinterpret_cast<pml4t_t>(0x70000);
+    if(!(reinterpret_cast<uintptr_t>(pml4t[pml4]) & PRESENT)){
+        return false;
+    }
+
+    auto pdpt = reinterpret_cast<pdpt_t>(reinterpret_cast<uintptr_t>(pml4t[pml4]) & ~0xFFF);
+    if(!(reinterpret_cast<uintptr_t>(pdpt[directory_ptr]) & PRESENT)){
+        return false;
+    }
+
+    auto pdt = reinterpret_cast<pdt_t>(reinterpret_cast<uintptr_t>(pdpt[directory_ptr]) & ~0xFFF);
+    if(!(reinterpret_cast<uintptr_t>(pdt[directory]) & PRESENT)){
+        return false;
+    }
+
+    auto pt = reinterpret_cast<pt_t>(reinterpret_cast<uintptr_t>(pdt[directory]) & ~0xFFF);
+    return reinterpret_cast<uintptr_t>(pt[table]) & PRESENT;
+}
+
+bool paging::page_free_or_set(void* virt, void* physical){
+    if(!page_present(virt)){
+        return true;
+    }
+
+    if(physical_address(virt) == physical){
+        return true;
+    }
+
+    return false;
+}
+
+bool paging::identity_map(void* virt){
     //The address must be page-aligned
-    if(reinterpret_cast<uintptr_t>(physical) % PAGE_SIZE != 0){
+    if(!page_aligned(virt)){
         return false;
     }
 
     //Find the correct indexes inside the paging table for the physical address
-    auto table = (reinterpret_cast<uintptr_t>(physical) >> 12) & 0x1FF;
-    auto directory = (reinterpret_cast<uintptr_t>(physical) >> 21) & 0x1FF;
-    auto directory_ptr = (reinterpret_cast<uintptr_t>(physical) >> 30) & 0x1FF;
-    auto pml4 = (reinterpret_cast<uintptr_t>(physical) >> 39) & 0x1FF;
+    auto table = (reinterpret_cast<uintptr_t>(virt) >> 12) & 0x1FF;
+    auto directory = (reinterpret_cast<uintptr_t>(virt) >> 21) & 0x1FF;
+    auto directory_ptr = (reinterpret_cast<uintptr_t>(virt) >> 30) & 0x1FF;
+    auto pml4 = (reinterpret_cast<uintptr_t>(virt) >> 39) & 0x1FF;
 
-    //Find the entries
     pml4t_t pml4t = reinterpret_cast<pml4t_t>(0x70000);
+
+    //Init new page if necessary
+    if(!(reinterpret_cast<uintptr_t>(pml4t[pml4]) & PRESENT)){
+        pml4t[pml4] = reinterpret_cast<pdpt_t>(init_new_page() | (PRESENT | WRITEABLE));
+    }
+
     auto pdpt = reinterpret_cast<pdpt_t>(reinterpret_cast<uintptr_t>(pml4t[pml4]) & ~0xFFF);
+
+    //Init new page if necessary
+    if(!(reinterpret_cast<uintptr_t>(pdpt[directory_ptr]) & PRESENT)){
+        pdpt[directory_ptr] = reinterpret_cast<pdt_t>(init_new_page() | (PRESENT | WRITEABLE));
+    }
+
     auto pdt = reinterpret_cast<pdt_t>(reinterpret_cast<uintptr_t>(pdpt[directory_ptr]) & ~0xFFF);
+
+    //Init new page if necessary
+    if(!(reinterpret_cast<uintptr_t>(pdt[directory]) & PRESENT)){
+        pdt[directory] = reinterpret_cast<pt_t>(init_new_page() | (PRESENT | WRITEABLE));
+    }
+
     auto pt = reinterpret_cast<pt_t>(reinterpret_cast<uintptr_t>(pdt[directory]) & ~0xFFF);
 
-    //Identity map  the physical address
-    pt[table] = reinterpret_cast<page_entry>(reinterpret_cast<uintptr_t>(physical) | 0x3);
+    //Check if the page is already present
+    if(reinterpret_cast<uintptr_t>(pt[table]) & PRESENT){
+        //If the page is already set to the correct value, return true
+        //If the page is set to another value, return false
+        return reinterpret_cast<uintptr_t>(pt[table]) == (reinterpret_cast<uintptr_t>(virt) | (PRESENT | WRITEABLE));
+    }
 
-    //TODO Check if pt[table] is already used and if so, return false
+    //Identity map  the physical address
+    pt[table] = reinterpret_cast<page_entry>(reinterpret_cast<uintptr_t>(virt) | (PRESENT | WRITEABLE));
 
     return true;
 }
 
-bool paging::identity_map(void* physical, size_t pages){
+bool paging::identity_map(void* virt, size_t pages){
     //The address must be page-aligned
-    if(reinterpret_cast<uintptr_t>(physical) % PAGE_SIZE != 0){
+    if(!page_aligned(virt)){
         return false;
     }
 
-    //TODO This should first check each page for the present bit
-
+    //To avoid mapping only a subset of the pages
+    //check if one of the page is already mapped to another value
     for(size_t page = 0; page < pages; ++page){
-        if(!identity_map(reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(physical) + page * PAGE_SIZE))){
+        auto addr = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(virt) + page * PAGE_SIZE);
+        if(!page_free_or_set(addr, addr)){
+            return false;
+        }
+    }
+
+    //Identity map each page
+    for(size_t page = 0; page < pages; ++page){
+        if(!identity_map(reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(virt) + page * PAGE_SIZE))){
             return false;
         }
     }
diff --git a/kernel/src/shell.cpp b/kernel/src/shell.cpp
index 814a92e6..d1f76ec4 100644
--- a/kernel/src/shell.cpp
+++ b/kernel/src/shell.cpp
@@ -516,9 +516,11 @@ void cat_command(const vector<string>& params){
 }
 
 void shutdown_command(const vector<string>&){
-    k_print_line("Init ACPI");
+    if(!acpi::init()){
+        k_print_line("Unable to init ACPI");
+    }
 
-    acpi::init();
+    acpi::shutdown();
 }
 
 } //end of anonymous namespace
diff --git a/kernel/src/sysinfo.cpp b/kernel/src/sysinfo.cpp
index 7b5dd21f..de8957d0 100644
--- a/kernel/src/sysinfo.cpp
+++ b/kernel/src/sysinfo.cpp
@@ -36,7 +36,7 @@ void decode_bytes (int data, int descriptor[16], int *next){
 }
 
 void get_cache_info() {
-    int next = 0, i = 0;
+    /*int next = 0, i = 0;
     int descriptor[256];
     int mem_count;
 
@@ -199,7 +199,7 @@ void get_cache_info() {
             k_print_line("  64-byte prefetching");
         if ( descriptor[i] ==  0xF1)
             k_print_line("  128-byte prefetching");
-    }
+    }*/
 }
 
 // EDX Features
diff --git a/kernel/src/utils.cpp b/kernel/src/utils.cpp
index 4fb63530..3e438610 100644
--- a/kernel/src/utils.cpp
+++ b/kernel/src/utils.cpp
@@ -8,6 +8,16 @@
 #include "utils.hpp"
 #include "string.hpp"
 
+void memset(void* ptr, unsigned char value, size_t num){
+    auto p = static_cast<unsigned char*>(ptr);
+
+    --p;
+
+    while(num--){
+        *++p = value;
+    }
+}
+
 bool str_equals(const char* a, const char* b){
     while(*a && *a == *b){
         ++a;