diff --git a/a.out b/a.out
new file mode 100755
index 0000000..df8e890
Binary files /dev/null and b/a.out differ
diff --git a/exo1 b/exo1
new file mode 100755
index 0000000..6d7d7fc
Binary files /dev/null and b/exo1 differ
diff --git a/exo2 b/exo2
new file mode 100755
index 0000000..7804849
Binary files /dev/null and b/exo2 differ
diff --git a/exo2.1 b/exo2.1
new file mode 100755
index 0000000..55d4ca6
Binary files /dev/null and b/exo2.1 differ
diff --git a/exo2.2 b/exo2.2
new file mode 100755
index 0000000..0529662
Binary files /dev/null and b/exo2.2 differ
diff --git a/exo2.c b/exo2.c
new file mode 100644
index 0000000..f3c7195
--- /dev/null
+++ b/exo2.c
@@ -0,0 +1,15 @@
+/* segment bss et data */
+#define N 100000
+//int t[N]; /* version 1 */
+int t[N]={1}; /* version 2 */
+
+int main()
+{
+	return 0;
+}
+
+
+
+// 1) Le tableau se trouve dans les données car la variables est globale. La taille n'a pas changé malgrès le changement de variables globale. 
+// 2) La deuxième version est plus lourde.
+
diff --git a/exo3 b/exo3
new file mode 100755
index 0000000..ea6bc6f
Binary files /dev/null and b/exo3 differ
diff --git a/exo3.1 b/exo3.1
new file mode 100755
index 0000000..8c0ec1f
Binary files /dev/null and b/exo3.1 differ
diff --git a/exo3.c b/exo3.c
new file mode 100644
index 0000000..f32ac86
--- /dev/null
+++ b/exo3.c
@@ -0,0 +1,31 @@
+/* accès mémoire */
+#include<stdio.h>
+#include<time.h>
+#include <stdlib.h>
+#define N 8192 
+
+int t[N][N];
+
+static inline double tstamp(void) 
+{                             
+	struct timespec tv;
+	clock_gettime(CLOCK_REALTIME, &tv);
+	return tv.tv_sec + tv.tv_nsec * 1.0e-9;
+}
+
+int main()
+{
+	int i,j;
+	double t1,t2;
+	t1=tstamp();
+	/* version 1 */  //   for(i=0;i<N;i++) for(j=0;j<N;j++) t[i][j] = 1;  
+	/* version 2 */   for(i=0;i<N;i++) for(j=0;j<N;j++) t[j][i] = 1;  
+	t2=tstamp();
+	printf("time = %lf\n",t2-t1);
+	return 0;
+}
+
+
+// Le temps est différents entre les deux versions du programme, Pourquoi ? 
+// Overload de cache, la mémoire parcours le tableau en ligne.    
+// t[n][n] 
\ No newline at end of file
diff --git a/exo4 b/exo4
new file mode 100755
index 0000000..df8e890
Binary files /dev/null and b/exo4 differ
diff --git a/exo4.c b/exo4.c
new file mode 100644
index 0000000..7a719a8
--- /dev/null
+++ b/exo4.c
@@ -0,0 +1,86 @@
+#include<stdio.h>
+#include<time.h>
+#include<stdlib.h>
+#include<string.h>
+#include<assert.h>
+static inline double tstamp(void) 
+{                                                                                    
+	struct timespec tv;
+	clock_gettime(CLOCK_REALTIME, &tv);
+	return tv.tv_sec + tv.tv_nsec * 1.0e-9;
+}
+void shuffle(int *array, size_t n)
+{
+	if (n > 1)
+	{
+		size_t i;
+//		for (i = 0; i < n - 1; i++)
+		for (i = 0; i < n ; i++)
+		{
+//			size_t j = i + rand() / (RAND_MAX / (n - i) + 1);
+			size_t j = rand()%n;
+			int t = array[j];
+			array[j] = array[i];
+			array[i] = t;
+		}
+	}
+}
+void init_access_c(int access[],size_t size)
+{
+	int i;
+	for(i=0;i<size;i++) access[i] = i;
+}
+void init_access_d(int access[],size_t size)
+{
+	int i;
+	for(i=0;i<size;i++) access[i] = size-i-1;
+}
+void init_access_a(int access[],size_t size)
+{
+	init_access_c(access,size);
+	shuffle(access,size);
+}
+void init_array(int t[],int N)
+{
+	int i;
+	for(i=0;i<N;i++) t[i] = i ;
+}
+long int sum_array(int t[],int access[],size_t size)
+{
+	long int S=0;
+	int i;
+	for(i=0;i<size;i++) S += t[access[i]];
+	return S;
+}
+int main(int argc,char * argv[])
+{
+	double t1,t2;
+	int * array; // tableau à sommer (contient les tous les entiers [0,SIZE-1]
+	int * access;
+	int i,size;
+	long	int  S=0;
+	if (argc !=3) {
+		printf("%s -c|-d|-a SIZE\n",argv[0]);
+		return 1;
+	}
+	size=strtol(argv[2],NULL,0);
+	array=(int *)malloc(sizeof(int)*size);
+	assert(array != NULL);
+	access=(int *)malloc(sizeof(int)*size);
+	assert(access != NULL);
+	init_array(array,size);
+	if (strcmp(argv[1],"-c") == 0)
+		init_access_c(access,size);
+	if (strcmp(argv[1],"-d") == 0)
+		init_access_d(access,size);
+	if (strcmp(argv[1],"-a") == 0)
+		init_access_a(access,size);
+	/* On somme les elements en accedant au tableau 
+	 * sequentiellement (croissant/décroissant), ou 
+	 * de manière aléatoire
+	 * */
+	t1=tstamp();
+	S= sum_array(array,access,size);
+	t2=tstamp();
+	printf("S=%ld %lf\n",S,(t2-t1));
+}