diff --git a/src/os/file.go b/src/os/file.go
index 96df3fb5e90fb24a3db90659fb3d585f29834a5a..c13babe5f7fad8ee418dc1783fc8e7e7413aea4e 100644
--- a/src/os/file.go
+++ b/src/os/file.go
@@ -34,6 +34,10 @@
 //	}
 //	fmt.Printf("read %d bytes: %q\n", count, data[:count])
 //
+// Note: The maximum number of concurrent operations on a File may be limited by
+// the OS or the system. The number should be high, but exceeding it may degrade
+// performance or cause other issues.
+//
 package os
 
 import (