diff --git a/scheme/ikarus.boot.prebuilt b/scheme/ikarus.boot.prebuilt
index 017da69..a329bc1 100644
Binary files a/scheme/ikarus.boot.prebuilt and b/scheme/ikarus.boot.prebuilt differ
diff --git a/scheme/ikarus.compiler.ss b/scheme/ikarus.compiler.ss
index ef22708..5903a88 100644
--- a/scheme/ikarus.compiler.ss
+++ b/scheme/ikarus.compiler.ss
@@ -1981,7 +1981,9 @@
   (define disp-port-set-position!  36)
   (define disp-port-close          40)
   (define disp-port-cookie         44)
-  (define port-size                48)
+  (define disp-port-position       48)
+  (define disp-port-unused         52)
+  (define port-size                56)
 
   (define disp-tcbucket-tconc 0)
   (define disp-tcbucket-key   4)
diff --git a/scheme/ikarus.io.ss b/scheme/ikarus.io.ss
index a63ce46..b578228 100644
--- a/scheme/ikarus.io.ss
+++ b/scheme/ikarus.io.ss
@@ -13,24 +13,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-#;
-(library (ikarus system $io tmp)
-  (export $make-port $port-tag $port-id $port-cookie
-          port? $port-transcoder 
-          $port-index $port-size $port-buffer 
-          $port-get-position $port-set-position! $port-close
-          $port-read! $port-write! $set-port-index! $set-port-size!
-          $port-attrs $set-port-attrs!)
-  (import (except (ikarus) port?))
-  (define-struct $port 
-    (attrs index size buffer transcoder 
-     id read! write! get-position set-position! close cookie))
-  (define port? $port?)
-  (define $set-port-index! set-$port-index!)
-  (define $set-port-size! set-$port-size!)
-  (define $set-port-attrs! set-$port-attrs!)
-  (define $make-port make-$port)
-  (define ($port-tag x) (if ($port? x) ($port-attrs x) 0)))
 
 (library (io-spec) 
   
@@ -131,7 +113,6 @@
      integer->char char->integer
      string-ref string-set! string-length
      bytevector-u8-ref bytevector-u8-set!)
-
     (import 
       (rename (ikarus system $strings)
         ($string-length string-length)
@@ -165,7 +146,6 @@
       [(_ name)
        (define (name . args) 
          (apply die 'name "not implemented" args))]))
-
  
   (define-syntax u8?
     (let ()
diff --git a/scheme/last-revision b/scheme/last-revision
index 837dd96..771034c 100644
--- a/scheme/last-revision
+++ b/scheme/last-revision
@@ -1 +1 @@
-1258
+1259
diff --git a/scheme/pass-specify-rep-primops.ss b/scheme/pass-specify-rep-primops.ss
index 69d2452..eaae90e 100644
--- a/scheme/pass-specify-rep-primops.ss
+++ b/scheme/pass-specify-rep-primops.ss
@@ -1771,6 +1771,8 @@
      (prm 'mset p (K (- disp-port-set-position! vector-tag)) (T setp))
      (prm 'mset p (K (- disp-port-close vector-tag)) (T cl))
      (prm 'mset p (K (- disp-port-cookie vector-tag)) (T cookie))
+     (prm 'mset p (K (- disp-port-position vector-tag)) (K 0))
+     (prm 'mset p (K (- disp-port-unused vector-tag)) (K 0))
      p)])
 
 (define-primop $port-index unsafe
diff --git a/src/ikarus-data.h b/src/ikarus-data.h
index 3722f32..ac1f03c 100644
--- a/src/ikarus-data.h
+++ b/src/ikarus-data.h
@@ -413,7 +413,7 @@ ikp ik_safe_alloc(ikpcb* pcb, int size);
 
 #define port_tag      0x3F
 #define port_mask     0x3F
-#define port_size       48
+#define port_size       56
 
 #define disp_tcbucket_tconc        0
 #define disp_tcbucket_key          4