diff --git a/src/machine.rs b/src/machine.rs
index 5fae20c..0d0aa86 100644
--- a/src/machine.rs
+++ b/src/machine.rs
@@ -1,6 +1,5 @@
 use std::io::{Read, Write};
-use std::sync::Mutex;
-use std::rc::Rc;
+use std::sync::{Mutex, Arc};
 
 use Result;
 use block::Block;
@@ -32,7 +31,7 @@ pub struct Machine {
     pub heap: Heap,
 
     pub stream_in: Box<Read + Send + Sync>,
-    pub stream_out: Rc<Mutex<Write + Send + Sync>>,
+    pub stream_out: Arc<Mutex<Write + Send + Sync>>,
 
 }
 
@@ -45,7 +44,7 @@ impl Machine {
             block,
             frame: vec![Frame::new(ANTI_BS_SIZE)],
             stream_in: Box::new(::std::io::stdin()),
-            stream_out: Rc::new(Mutex::new(::std::io::stdout())),
+            stream_out: Arc::new(Mutex::new(::std::io::stdout())),
 
             #[cfg(feature = "bonus:network")]
             net: NetStack::new(),
@@ -152,7 +151,7 @@ impl Machine {
         self.stream_in = instream;
     }
 
-    pub fn set_output(&mut self, outstream: Rc<Mutex<Write + Send + Sync>>) {
+    pub fn set_output(&mut self, outstream: Arc<Mutex<Write + Send + Sync>>) {
         self.stream_out = outstream;
     }
 }
\ No newline at end of file
diff --git a/tests/advanced1.rs b/tests/advanced1.rs
index 8b498a6..42eff32 100644
--- a/tests/advanced1.rs
+++ b/tests/advanced1.rs
@@ -1,7 +1,6 @@
 extern crate rustijvm;
 
-use std::rc::Rc;
-use std::sync::Mutex;
+use std::sync::{Arc, Mutex};
 use std::io::{Cursor, Seek, SeekFrom, Read};
 
 fn steps(machine: &mut rustijvm::Machine, num: usize) {
@@ -12,7 +11,7 @@ fn steps(machine: &mut rustijvm::Machine, num: usize) {
 
 #[test]
 fn advanced1() {
-    let output: Rc<Mutex<Cursor<Vec<u8>>>> = Rc::new(Mutex::new(Cursor::new(Vec::new())));
+    let output: Arc<Mutex<Cursor<Vec<u8>>>> = Arc::new(Mutex::new(Cursor::new(Vec::new())));
     let input = Box::new("A".as_bytes());
     let mut machine = rustijvm::Machine::new_from_file("files/task5/all_regular.ijvm").unwrap();
     machine.set_input(input);
diff --git a/tests/advanced4.rs b/tests/advanced4.rs
index 4ef1d75..bf11e29 100644
--- a/tests/advanced4.rs
+++ b/tests/advanced4.rs
@@ -1,12 +1,11 @@
 extern crate rustijvm;
 
-use std::rc::Rc;
-use std::sync::Mutex;
+use std::sync::{Arc, Mutex};
 use std::io::{Cursor, Seek, SeekFrom, Read};
 
 #[test]
 fn advanced4_tanenbaum() {
-    let rc = Rc::new(Mutex::new(Cursor::new(Vec::new())));
+    let rc = Arc::new(Mutex::new(Cursor::new(Vec::new())));
     let mut machine = rustijvm::Machine::new_from_file("files/advanced/Tanenbaum.ijvm").unwrap();
     machine.set_output(rc.clone());
     machine.run().unwrap();
diff --git a/tests/bonusheap.rs b/tests/bonusheap.rs
index a763b9b..e3289be 100644
--- a/tests/bonusheap.rs
+++ b/tests/bonusheap.rs
@@ -1,13 +1,12 @@
 extern crate rustijvm;
 
 use std::fs::File;
-use std::rc::Rc;
-use std::sync::Mutex;
+use std::sync::{Arc, Mutex};
 use std::io::{Cursor, Seek, SeekFrom, Read};
 
 fn run_bfi(file: &str) -> String {
     let file = File::open(file).expect("Missing bf file");
-    let rc = Rc::new(Mutex::new(Cursor::new(Vec::new())));
+    let rc = Arc::new(Mutex::new(Cursor::new(Vec::new())));
     let mut machine = rustijvm::Machine::new_from_file("files/bonus/bfi.ijvm").unwrap();
     machine.set_output(rc.clone());
     machine.set_input(Box::new(file));
diff --git a/tests/task4.rs b/tests/task4.rs
index 41f598b..15ca0c4 100644
--- a/tests/task4.rs
+++ b/tests/task4.rs
@@ -1,8 +1,7 @@
 extern crate rustijvm;
 
 use std::io::{Cursor, Read, Seek, SeekFrom};
-use std::rc::Rc;
-use std::sync::Mutex;
+use std::sync::{Arc, Mutex};
 
 fn steps(machine: &mut rustijvm::Machine, num: usize) {
     for _ in 0..num {
@@ -84,7 +83,7 @@ fn task4_complex_load() {
 
 #[test]
 fn task4_iteration_load() {
-    let rc = Rc::new(Mutex::new(Cursor::new(Vec::new())));
+    let rc = Arc::new(Mutex::new(Cursor::new(Vec::new())));
 
     let mut machine = rustijvm::Machine::new_from_file("files/task4/LoadTest4.ijvm").unwrap();
     machine.set_output(rc.clone());