diff --git a/scsh/sighandlers.scm b/scsh/sighandlers.scm
index 8877866..f884682 100644
--- a/scsh/sighandlers.scm
+++ b/scsh/sighandlers.scm
@@ -210,12 +210,15 @@
 	  (vector-set! interrupt-handlers i
 		       (vector-ref default-int-handler-vec i))))))
 
+;;; I am ashamed to say the 33 below is completely bogus.
+;;; What we want is a value that is 1 + max interrupt value.
+
 (define int->sig-vec
-  (let ((v (make-vector 32 #f)))
+  (let ((v (make-vector 33 #f)))
     (do ((sig 32 (- sig 1)))
 	((< sig 0))
       (let ((i (%signal->interrupt sig)))
-	(if (not (= i -1)) (vector-set! v sig i))))
+	(if (not (= i -1)) (vector-set! v i sig))))
     v))
 
 (define (int->signal i) (and (<= 0 i 32) (vector-ref int->sig-vec i)))