diff --git a/cook-port.rkt b/cook-port.rkt
index a9158f4..d1cda94 100644
--- a/cook-port.rkt
+++ b/cook-port.rkt
@@ -45,26 +45,30 @@
   (define-values (cooked-in cooked-out) (make-pipe))
   (thread
    (lambda ()
+     (define input-buffer (make-bytes 4096))
      (let loop ((b (buffer '() #f)))
        (if (port-closed? cooked-out)
 	   ;; our job here is
 	   'done
-	   (let ((s (read-string 1 raw-in)))
-	     (if (eof-object? s)
+	   (let ((count (read-bytes-avail! input-buffer raw-in)))
+	     (if (eof-object? count)
 		 (begin (close-output-port cooked-out)
 			(loop b))
-		 (begin (update-buffer b (string-ref s 0) prompt
-				       (lambda ()
-					 (close-output-port cooked-out)
-					 (close-input-port raw-in))
-				       (lambda (line new-b)
-					 (write-string "\r\n" raw-out)
-					 (write-string line cooked-out)
-					 (newline cooked-out)
-					 (loop new-b))
-				       (lambda (new-b feedback)
-					 (write-string feedback raw-out)
-					 (loop new-b))))))))))
+		 (let process-bytes ((i 0) (b b))
+		   (if (>= i count)
+		       (loop b)
+		       (update-buffer b (integer->char (bytes-ref input-buffer i)) prompt
+				      (lambda ()
+					(close-output-port cooked-out)
+					(close-input-port raw-in))
+				      (lambda (line new-b)
+					(write-string "\r\n" raw-out)
+					(write-string line cooked-out)
+					(newline cooked-out)
+					(process-bytes (+ i 1) new-b))
+				      (lambda (new-b feedback)
+					(write-string feedback raw-out)
+					(process-bytes (+ i 1) new-b)))))))))))
   (values cooked-in (cook-output raw-out)))
 
 (define (cook-output raw-out)