diff --git a/threads/collatz.c b/process_chp3/collatz.c
similarity index 100%
rename from threads/collatz.c
rename to process_chp3/collatz.c
diff --git a/threads/collatz_shm.c b/process_chp3/collatz_shm.c
similarity index 100%
rename from threads/collatz_shm.c
rename to process_chp3/collatz_shm.c
diff --git a/threads/collatz_shm2.c b/process_chp3/collatz_shm2.c
similarity index 100%
rename from threads/collatz_shm2.c
rename to process_chp3/collatz_shm2.c
diff --git a/threads/cons.c b/process_chp3/cons.c
similarity index 100%
rename from threads/cons.c
rename to process_chp3/cons.c
diff --git a/threads/ex1.c b/process_chp3/ex1.c
similarity index 100%
rename from threads/ex1.c
rename to process_chp3/ex1.c
diff --git a/threads/ex12.c b/process_chp3/ex12.c
similarity index 100%
rename from threads/ex12.c
rename to process_chp3/ex12.c
diff --git a/threads/ex13.c b/process_chp3/ex13.c
similarity index 100%
rename from threads/ex13.c
rename to process_chp3/ex13.c
diff --git a/threads/ex14.c b/process_chp3/ex14.c
similarity index 100%
rename from threads/ex14.c
rename to process_chp3/ex14.c
diff --git a/threads/ex17.c b/process_chp3/ex17.c
similarity index 100%
rename from threads/ex17.c
rename to process_chp3/ex17.c
diff --git a/threads/ex19.c b/process_chp3/ex19.c
similarity index 100%
rename from threads/ex19.c
rename to process_chp3/ex19.c
diff --git a/threads/pid_manager.c b/process_chp3/pid_manager.c
similarity index 100%
rename from threads/pid_manager.c
rename to process_chp3/pid_manager.c
diff --git a/threads/pid_manager.h b/process_chp3/pid_manager.h
similarity index 100%
rename from threads/pid_manager.h
rename to process_chp3/pid_manager.h
diff --git a/threads/prod.c b/process_chp3/prod.c
similarity index 100%
rename from threads/prod.c
rename to process_chp3/prod.c
diff --git a/threads/bitmap.c b/threads/bitmap.c
deleted file mode 100644
index c738724..0000000
--- a/threads/bitmap.c
+++ /dev/null
@@ -1,85 +0,0 @@
-#include "bitmap.h"
-#include <stdio.h>
-#include <stdlib.h>
-
-#ifdef bitmap_64
-#define bitmap_type unsigned long long int
-#define bitmap_shift 6
-#define bitmap_mask 63
-#define bitmap_wordlength 64
-#define bitmap_fmt "%016llx"
-#else // assumed to be 32 bits
-#define bitmap_type unsigned int
-#define bitmap_shift 5
-#define bitmap_mask 31
-#define bitmap_wordlength 32
-#define bitmap_fmt "%08x"
-#endif
-
-// get the types right
-#define bitmap_one (bitmap_type)1
-
-// we expect 0 <= n and n < b->bits, but it is not verified
-
-// arch a 8 bit
-// bitmap shift 3
-// wordlength 8
-
-// n = 10 -> 00001010
-// 00000001 -> word = 1
-//
-// n = 12 ->   00001100
-// mask = 7 -> 00000111
-//             00000100 = 4
-// 00000001 -> word = 1
-//
-// n = 32 ->    00100000
-// mask = 7 ->  00000111
-// 00000000
-// 00000100 -> word = 4
-//
-// n = 127 ->      01111111
-// mask = 7 ->     00000111
-// position = 7 -> 00000111
-//
-
-void bitmap_set(bitmap *b, int n) {
-  int word = n >> bitmap_shift;   // n / bitmap_wordlength
-  int position = n & bitmap_mask; // n % bitmap_wordlength
-  b->array[word] |= bitmap_one << position;
-}
-
-void bitmap_clear(bitmap *b, int n) {
-  int word = n >> bitmap_shift;   // n / bitmap_wordlength
-  int position = n & bitmap_mask; // n % bitmap_wordlength
-  b->array[word] &= ~(bitmap_one << position);
-}
-
-int bitmap_read(bitmap *b, int n) {
-  int word = n >> bitmap_shift;   // n / bitmap_wordlength
-  int position = n & bitmap_mask; // n % bitmap_wordlength
-  return (b->array[word] >> position) & 1;
-}
-
-bitmap *bitmap_allocate(int bits) {
-  // error-checking should be better :-)
-  bitmap *b = malloc(sizeof(bitmap));
-  b->bits = bits;
-  b->words = (bits + bitmap_wordlength - 1) / bitmap_wordlength;
-  // divide, but round up for the ceiling
-  b->array = calloc(b->words, sizeof(bitmap_type));
-  return b;
-}
-
-void bitmap_deallocate(bitmap *b) {
-  // error-checking should be better :-)
-  free(b->array);
-  free(b);
-}
-
-void bitmap_print(bitmap *b) {
-  for (int i = 0; i < b->words; i++) {
-    printf(" " bitmap_fmt, b->array[i]);
-  }
-  printf("\n");
-}
diff --git a/threads/bitmap.h b/threads/bitmap.h
deleted file mode 100644
index 7b4d45d..0000000
--- a/threads/bitmap.h
+++ /dev/null
@@ -1,22 +0,0 @@
-// use dynamic allocation with these functions
-// compile with -Dbitmap_64 to force 64-bit words
-// compile with -O [dash capital o] for more efficient machine code
-
-#ifdef bitmap_64
-#define bitmap_type unsigned long long int
-#else // assumed to be 32 bits
-#define bitmap_type unsigned int
-#endif
-
-typedef struct {
-  int bits;  // number of bits in the array
-  int words; // number of words in the array
-  bitmap_type *array;
-} bitmap;
-
-void bitmap_set(bitmap *b, int n); // n is a bit index
-void bitmap_clear(bitmap *b, int n);
-int bitmap_read(bitmap *b, int n);
-bitmap *bitmap_allocate(int bits);
-void bitmap_deallocate(bitmap *b);
-void bitmap_print(bitmap *b);
diff --git a/threads/test.c b/threads/test.c
deleted file mode 100644
index 8ec4683..0000000
--- a/threads/test.c
+++ /dev/null
@@ -1,7 +0,0 @@
-#include <stdio.h>
-
-int main(void) {
-  int n;
-  printf("%d\n", n);
-  return 0;
-}
diff --git a/threads/ex417.c b/threads_chp4/ex417.c
similarity index 100%
rename from threads/ex417.c
rename to threads_chp4/ex417.c
diff --git a/threads/ex421.c b/threads_chp4/ex421.c
similarity index 100%
rename from threads/ex421.c
rename to threads_chp4/ex421.c
diff --git a/threads/ex424.c b/threads_chp4/ex424.c
similarity index 100%
rename from threads/ex424.c
rename to threads_chp4/ex424.c
diff --git a/threads/ex426.c b/threads_chp4/ex426.c
similarity index 100%
rename from threads/ex426.c
rename to threads_chp4/ex426.c
diff --git a/threads/pid_manager_thread_chp4.c b/threads_chp4/pid_manager.c
similarity index 100%
rename from threads/pid_manager_thread_chp4.c
rename to threads_chp4/pid_manager.c
diff --git a/threads_chp4/pid_manager.h b/threads_chp4/pid_manager.h
new file mode 100644
index 0000000..e116507
--- /dev/null
+++ b/threads_chp4/pid_manager.h
@@ -0,0 +1,16 @@
+#if !defined(__PID_MANGER_H__)
+#define __PID_MANGER_H__
+#define _GNU_SOURCE
+
+// Crea e inizializza una struttura per rappresentare i pid;
+// restituisce -1 in caso di insuccesso e 1 in caso di successo.
+int allocate_map(void);
+
+// Alloca e restituisce un pid, restituisce -1 se non è possibile
+// assegnare un PID (tutti i pid sono in uso).
+int allocate_pid(void);
+
+// Rilascia un pid
+void release_pid(int pid);
+
+#endif
diff --git a/threads/project2.c b/threads_chp4/project2.c
similarity index 100%
rename from threads/project2.c
rename to threads_chp4/project2.c