diff --git a/benchmarks.larceny/results.Larceny-r6rs b/benchmarks.larceny/results.Larceny-r6rs
index a32f619..8322b92 100644
--- a/benchmarks.larceny/results.Larceny-r6rs
+++ b/benchmarks.larceny/results.Larceny-r6rs
@@ -8534,3 +8534,23 @@ Words allocated: 36171538
 Words reclaimed: 0
 Elapsed time...: 5849 ms (User: 5815 ms; System: 31 ms)
 Elapsed GC time: 83 ms (CPU: 86 in 138 collections.)
+
+****************************
+Benchmarking Larceny-r6rs on Tue Nov 13 03:44:36 EST 2007 under Darwin Vesuvius.local 8.10.1 Darwin Kernel Version 8.10.1: Wed May 23 16:33:00 PDT 2007; root:xnu-792.22.5~1/RELEASE_I386 i386 i386
+
+Testing ray under Larceny-r6rs
+Compiling...
+Larceny v0.95 "First Safety" (Nov  8 2007 04:30:20, precise:BSD Unix:unified)
+larceny.heap, built on Thu Nov  8 04:39:44 EST 2007
+
+> 
+> 
+Running...
+Larceny v0.95 "First Safety" (Nov  8 2007 04:30:20, precise:BSD Unix:unified)
+larceny.heap, built on Thu Nov  8 04:39:44 EST 2007
+
+> 
+Words allocated: 220925448
+Words reclaimed: 0
+Elapsed time...: 20757 ms (User: 10967 ms; System: 9775 ms)
+Elapsed GC time: 179 ms (CPU: 176 in 843 collections.)
diff --git a/benchmarks/rnrs-benchmarks.ss b/benchmarks/rnrs-benchmarks.ss
index 1334e04..6ae58fa 100644
--- a/benchmarks/rnrs-benchmarks.ss
+++ b/benchmarks/rnrs-benchmarks.ss
@@ -163,7 +163,7 @@
   (define peval-iters       400)
   (define pi-iters            3)
   (define primes-iters   180000)
-  (define ray-iters           3)
+  (define ray-iters           5)
   (define scheme-iters    40000)
   (define simplex-iters  160000)
   (define slatex-iters       30)
diff --git a/benchmarks/summarize.pl b/benchmarks/summarize.pl
index 5b7992b..29c5fa5 100755
--- a/benchmarks/summarize.pl
+++ b/benchmarks/summarize.pl
@@ -64,16 +64,16 @@ foreach my $bench (@benchmarks){
   foreach my $time (@times){
     defined $runtimes{$bench}{$time} or next;
     my @times = @{$runtimes{$bench}{$time}};
-    my $avg = average(@times);
+    my $t = min(@times);
     if($prev){
-      my $diff = (($avg - $prev) / $prev) * 100;
+      my $diff = (($t - $prev) / $prev) * 100;
       printf "   %6d %6s             on $time\n", 
-        $avg,
+        $t,
         sprintf("(%s%d%%)", ($diff>0) ? "+" : ($diff<0) ? "-" : "", abs $diff);
     } else {
-      printf "   %6d                    on $time\n", $avg;
+      printf "   %6d                    on $time\n", $t;
     }
-    $prev = $avg;
+    $prev = $t;
   }
 }
 
diff --git a/scheme/ikarus.numerics.ss b/scheme/ikarus.numerics.ss
index f8a3f40..3e51661 100644
--- a/scheme/ikarus.numerics.ss
+++ b/scheme/ikarus.numerics.ss
@@ -191,6 +191,7 @@
       (fx> b0 127)))
 
   (define ($flonum->exact x)
+    ;;; this really needs to get optimized.
     (let-values ([(pos? be m) (flonum-parts x)])
       (cond
         [(<= 1 be 2046) ; normalized flonum
diff --git a/scheme/ikarus.strings.ss b/scheme/ikarus.strings.ss
index 898c3b3..7c69309 100644
--- a/scheme/ikarus.strings.ss
+++ b/scheme/ikarus.strings.ss
@@ -125,16 +125,18 @@
          (let ([len ($string-length s)])
            (unless (and (fixnum? n)
                         ($fx>= n 0)
-                        ($fx< n len))
+                        ($fx<= n len))
              (error 'substring "not a valid start index" n s))
            (unless (and (fixnum? m)
                         ($fx>= m 0)
                         ($fx<= m len))
              (error 'substring "not a valid end index" m s))
+           (unless ($fx<= n m)
+             (error 'substring "indices are in decreasing order" n m))
            (let ([len ($fx- m n)])
-             (if ($fx<= len 0)
-                 ""
-                 (fill s ($make-string len) n m 0)))))))
+             (if ($fx> len 0)
+                 (fill s ($make-string len) n m 0)
+                 ""))))))
 
   (define string-copy 
     (lambda (s)