diff --git a/scheme/httpd/surflets/profile.scm b/scheme/httpd/surflets/profile.scm
index de218fd..96c17a2 100644
--- a/scheme/httpd/surflets/profile.scm
+++ b/scheme/httpd/surflets/profile.scm
@@ -22,7 +22,7 @@
 ;;; that contains all SPACE-INFO objects (see below for SPACE-INFO).
 ;;;
 ;;;
-;;; (MAKE-GNUPLOT-DATA output-file selector space-info-list)
+;;; (WRITE-GNUPLOT-DATA-FILE output-file selector space-info-list)
 ;;;
 ;;; Creates a file named OUTPUT-FILE out of SPACE-INFO-LIST. The
 ;;; created file can be used with GNUPLOT (external program, not part
@@ -107,13 +107,16 @@
 
 
 (define *run-count* 0)
+(define *temp-file-lock* (make-lock))
 
 ;; PROFILE-SPACE writes result of call to (SPACE) to a file
 (define (profile-space . maybe-file-name)
+  (obtain-lock *temp-file-lock*)
   (let ((file-name
 	 (:optional maybe-file-name
 		    (create-temp-file "/var/tmp/profile"))))
     (let ((out (open-output-file file-name open/append)))
+      (release-lock *temp-file-lock*)
       (set! *run-count* (+ 1 *run-count*))
       (format out "~%Run #~a~%" *run-count*)
       (with-current-output-port* out space)