diff --git a/src/data.rs b/src/data.rs
new file mode 100644
index 0000000..524aa6e
--- /dev/null
+++ b/src/data.rs
@@ -0,0 +1,22 @@
+//! Datatypes for the program
+use super::*;
+
+/// A raw file or directory inode number
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy)]
+#[repr(transparent)]
+pub struct INode(u64);
+
+impl INode
+{
+    /// Create a new `INode` wrapper from any `u64` without checking if it is a real inode.
+    #[inline] pub const unsafe fn new_unchecked(ino: u64) -> Self
+    {
+	Self(ino)
+    }
+
+    /// Convert into raw `u64` inode number.
+    #[inline] pub const fn into_inner(self) -> u64
+    {
+	self.0
+    }
+}
diff --git a/src/ext.rs b/src/ext.rs
index 71b1727..40df186 100644
--- a/src/ext.rs
+++ b/src/ext.rs
@@ -178,12 +178,55 @@ where S: Stream
     }
 }
 
+/// Create a duration with time suffix `h`, `m`, `s`, `ms` or `ns`.
+///
+/// # Combination
+/// These can also be combined.
+/// ```
+/// #use crate::duration;
+/// duration!(1 h, 20 m, 30 s);
+/// ```
+#[macro_export ]macro_rules! duration
+{
+    (0 $($_any:tt)?) => (::std::time::Duration::from_secs(0));
+    ($dur:literal ms) => (::std::time::Duration::from_millis($dur));
+    ($dur:literal ns) => (::std::time::Duration::from_nanos($dur));
+    ($dur:literal s) => (::std::time::Duration::from_secs($dur));
+    ($dur:literal m) => (::std::time::Duration::from_secs($dur * 60));
+    ($dur:literal h) => (::std::time::Duration::from_secs($dur * 60 * 60));
+    
+    ( $($dur:literal $unit:tt),*)=> {
+        duration!(0 s) $(
+            + duration!($dur $unit)
+        )*
+    };
+}
+
 
 #[cfg(test)]
 mod tests
 {
     use super::*;
     
+    #[test]
+    fn duration()
+    {
+	let dur = duration!(1 h) +
+	    duration!(10 m) +
+	    duration!(1 s) +
+	    duration!(10 ms, 2 ns);
+	println!("{:?}", dur);
+	let dur2 = duration!(
+	    1 h,
+	    10 m,
+	    1 s,
+	    10 ms,
+	    2 ns
+	);
+	println!("{:?}", dur2);
+	assert_eq!(dur, dur2);
+    }
+    
     #[tokio::test]
     async fn stream_gating_with_timeout()
     {
diff --git a/src/main.rs b/src/main.rs
index ef73180..947b354 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,9 +1,13 @@
 
+#![allow(dead_code)]
+
 #[macro_use] extern crate pin_project;
 
-mod ext;
+#[macro_use] mod ext;
 pub use ext::prelude::*;
 
+mod data;
+
 #[tokio::main]
 async fn main() {
     println!("Hello, world!");