diff --git a/src/libraries/OS-Posix/System/Time.dcl b/src/libraries/OS-Posix/System/Time.dcl
index fb625d0371cfcf4d010033ed8635309067439a51..ea10fce3e685e9c08016ca9ea43a2b691c45878e 100644
--- a/src/libraries/OS-Posix/System/Time.dcl
+++ b/src/libraries/OS-Posix/System/Time.dcl
@@ -90,3 +90,10 @@ toGmTime    :: !Timestamp -> Tm
  */
 nsTime :: !*World -> (!Timespec, !*World)
 :: Timespec = {tv_sec :: !Int, tv_nsec :: !Int}
+
+timespecToStamp :: !Timespec -> Timestamp
+timestampToSpec :: !Timestamp -> Timespec
+
+instance < Timespec
+instance + Timespec
+instance - Timespec
diff --git a/src/libraries/OS-Posix/System/Time.icl b/src/libraries/OS-Posix/System/Time.icl
index c982af4055865959e6cd38ad1eb370c70c94869b..9dea633f12451c3287c6ec7219c88a49dbd9d5a4 100644
--- a/src/libraries/OS-Posix/System/Time.icl
+++ b/src/libraries/OS-Posix/System/Time.icl
@@ -176,3 +176,30 @@ nsTime w
 # (tv_sec, p) = readIntP p 0
 # (tv_nsec, p) = readIntP p 8
 = ({Timespec | tv_sec = tv_sec, tv_nsec = tv_nsec}, freeSt p w)
+
+timespecToStamp :: !Timespec -> Timestamp
+timespecToStamp t = Timestamp t.tv_sec
+
+timestampToSpec :: !Timestamp -> Timespec
+timestampToSpec (Timestamp t) = {tv_sec=t,tv_nsec=0}
+
+instance < Timespec
+where
+	(<) t1 t2
+		| t1.tv_sec == t2.tv_sec = t1.tv_nsec < t2.tv_nsec
+		= t1.tv_sec < t2.tv_sec
+
+instance + Timespec
+where
+	(+) t1 t2 = let tv_nsec = t1.tv_nsec + t2.tv_nsec in
+		{ tv_sec  = t1.tv_sec + t2.tv_sec + tv_nsec / 1000000000
+		, tv_nsec = tv_nsec rem 1000000000
+		}
+
+instance - Timespec
+where
+	(-) t1 t2
+		# tv_nsec = t1.tv_nsec - t2.tv_nsec
+		| tv_nsec < 0
+			= {tv_sec = t1.tv_sec - t2.tv_sec - 1, tv_nsec = 1000000000 - tv_nsec}
+			= {tv_sec = t1.tv_sec - t2.tv_sec - 1, tv_nsec = tv_nsec}
diff --git a/src/libraries/OS-Windows/System/Time.dcl b/src/libraries/OS-Windows/System/Time.dcl
index 525c8b6f575b2f9c077fb4be9768c57566904aef..6c85d7991fd4de0ba9601d8e1b49776f8b6af9d5 100644
--- a/src/libraries/OS-Windows/System/Time.dcl
+++ b/src/libraries/OS-Windows/System/Time.dcl
@@ -94,3 +94,11 @@ gmTimeC :: !{#Int} -> Int
  */
 nsTime :: !*World -> (!Timespec, !*World)
 :: Timespec = {tv_sec :: !Int, tv_nsec :: !Int}
+
+timespecToStamp :: !Timespec -> Timestamp
+
+timestampToSpec :: !Timestamp -> Timespec
+
+instance < Timespec
+instance + Timespec
+instance - Timespec
diff --git a/src/libraries/OS-Windows/System/Time.icl b/src/libraries/OS-Windows/System/Time.icl
index 705c34d1b2381381d2e158f8e953afbb846a6a83..c0ebc10b513134e6b9474a766f3bee51c49d0f25 100644
--- a/src/libraries/OS-Windows/System/Time.icl
+++ b/src/libraries/OS-Windows/System/Time.icl
@@ -180,3 +180,30 @@ uintToInt :: Int -> Integer
 uintToInt i
 | i < 0 = toInteger i + {integer_s=0,integer_a={0,1}}
 = toInteger i
+
+timespecToStamp :: !Timespec -> Timestamp
+timespecToStamp t = Timestamp t.tv_sec
+
+timestampToSpec :: !Timestamp -> Timespec
+timestampToSpec (Timestamp t) = {tv_sec=t,tv_nsec=0}
+
+instance < Timespec
+where
+	(<) t1 t2
+		| t1.tv_sec == t2.tv_sec = t1.tv_nsec < t2.tv_nsec
+		= t1.tv_sec < t2.tv_sec
+
+instance + Timespec
+where
+	(+) t1 t2 = let tv_nsec = t1.tv_nsec + t2.tv_nsec in
+		{ tv_sec  = t1.tv_sec + t2.tv_sec + tv_nsec / 1000000000
+		, tv_nsec = tv_nsec rem 1000000000
+		}
+
+instance - Timespec
+where
+	(-) t1 t2
+		# tv_nsec = t1.tv_nsec - t2.tv_nsec
+		| tv_nsec < 0
+			= {tv_sec = t1.tv_sec - t2.tv_sec - 1, tv_nsec = 1000000000 - tv_nsec}
+			= {tv_sec = t1.tv_sec - t2.tv_sec - 1, tv_nsec = tv_nsec}