diff --git a/src/utility/mod.rs b/src/utility/mod.rs
index c6db391..85e59cc 100644
--- a/src/utility/mod.rs
+++ b/src/utility/mod.rs
@@ -1,3 +1,6 @@
+//! This module contains data type definitions used in other parts the BurritOS
+//! They are separated from the rest of the operating system so as to promote
+//! reusability and to separate data constructs proper from state and actions.
 pub mod list;
 pub mod objaddr;
 pub mod cfg;
\ No newline at end of file
diff --git a/src/utility/objaddr.rs b/src/utility/objaddr.rs
index 42ad0a5..b2847e6 100644
--- a/src/utility/objaddr.rs
+++ b/src/utility/objaddr.rs
@@ -17,9 +17,13 @@ use crate::kernel::{synch::{ Semaphore, Lock }, thread::Thread};
 /// calls.
 #[derive(PartialEq)]
 pub struct ObjAddr {
+    /// Id of the last added object
     last_id: i32,
+    /// List of [Semaphore] added in this struct. Each is keyed with a unique i32 id.
     semaphores: HashMap<i32, Semaphore>,
+    /// List of [Lock] added in this struct. Each is keyed with a unique i32 id.
     locks: HashMap<i32, Lock>,
+    /// List of threads known by this instance of ObjAddr (useful for managing lock ownership)
     threads: HashMap<i32, Rc<RefCell<Thread>>>,
 }