diff --git a/man7/signal.7 b/man7/signal.7
index 10fd3e9d3..0277a7d43 100644
--- a/man7/signal.7
+++ b/man7/signal.7
@@ -666,11 +666,12 @@ and
 calls on "slow" devices.
 A "slow" device is one where the I/O call may block for an
 indefinite time, for example, a terminal, pipe, or socket.
-(A disk is not a slow device according to this definition.)
 If an I/O call on a slow device has already transferred some
 data by the time it is interrupted by a signal handler,
 then the call will return a success status
 (normally, the number of bytes transferred).
+Note that a (local) disk is not a slow device according to this definition;
+I/O operations on disk devices are not interrupted by signals.
 .IP *
 .BR open (2),
 if it can block (e.g., when opening a FIFO; see