diff --git a/src/ikarus.boot b/src/ikarus.boot
index 077ab74..a7029e3 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/ikarus.compiler.ss b/src/ikarus.compiler.ss
index 5bc3827..7a911ea 100644
--- a/src/ikarus.compiler.ss
+++ b/src/ikarus.compiler.ss
@@ -1800,15 +1800,14 @@
   (define port-tag              #x3F)
   (define output-port-tag       #x7F)
   (define input-port-tag        #xBF)
-  ;(define input/output-port-tag #xFF)
   (define port-mask             #x3F)
   (define disp-port-buffer         4)
   (define disp-port-index          8)
   (define disp-port-size          12)
   (define disp-port-handler       16)
-  (define disp-port-output-buffer 20)
-  (define disp-port-output-index  24)
-  (define disp-port-output-size   28)
+  (define disp-port-unused1   20)
+  (define disp-port-unused2   24)
+  (define disp-port-unused3   28)
   (define port-size               32)
 
 
diff --git a/src/ikarus.io-ports.ss b/src/ikarus.io-ports.ss
index a2326da..751b6c2 100644
--- a/src/ikarus.io-ports.ss
+++ b/src/ikarus.io-ports.ss
@@ -55,7 +55,7 @@
   ;;;
   (define $make-input-port
     (lambda (handler buffer)
-      ($make-port/input handler buffer 0 ($bytevector-length buffer) #f 0 0)))
+      ($make-port/input handler buffer 0 ($bytevector-length buffer))))
   ;;;
   (define make-input-port
     (lambda (handler buffer)
@@ -67,7 +67,7 @@
   ;;;
   (define $make-output-port
     (lambda (handler buffer)
-      ($make-port/output handler #f 0 0 buffer 0 ($bytevector-length buffer))))
+      ($make-port/output handler buffer 0 ($bytevector-length buffer))))
   ;;;
   (define make-output-port
     (lambda (handler buffer)
@@ -77,22 +77,6 @@
               (error 'make-output-port "~s is not a bytevector" buffer))
           (error 'make-output-port "~s is not a procedure" handler))))
   ;;;
-  ;(define $make-input/output-port
-  ;  (lambda (handler input-buffer output-buffer)
-  ;     ($make-port/both handler
-  ;                input-buffer 0 ($bytevector-length input-buffer)
-  ;                output-buffer 0 ($bytevector-length output-buffer))))
-  ;;;
-  ;(define make-input/output-port
-  ;  (lambda (handler input-buffer output-buffer)
-  ;    (if (procedure? handler)
-  ;        (if (bytevector? input-buffer)
-  ;            (if (bytevector? output-buffer)
-  ;                ($make-input/output-port handler input-buffer output-buffer) 
-  ;                (error 'make-input/output-port "~s is not a bytevector" output-buffer))
-  ;            (error 'make-input/output-port "~s is not a bytevector" input-buffer))
-  ;        (error 'make-input/output-port "~s is not a procedure" handler))))
-  ;;;
   (define port-handler
     (lambda (x)
       (if (port? x)
@@ -120,19 +104,19 @@
   (define port-output-buffer
     (lambda (x)
       (if (output-port? x)
-          ($port-output-buffer x)
+          ($port-buffer x)
           (error 'port-output-buffer "~s is not an output-port" x))))
   ;;;
   (define port-output-index
     (lambda (x)
       (if (output-port? x)
-          ($port-output-index x)
+          ($port-index x)
           (error 'port-output-index "~s is not an output-port" x))))
   ;;;
   (define port-output-size
     (lambda (x)
       (if (output-port? x)
-          ($port-output-size x)
+          ($port-size x)
           (error 'port-output-size "~s is not an output-port" x))))
   ;;;
   (define set-port-input-index!
@@ -166,8 +150,8 @@
       (if (output-port? p)
           (if (fixnum? i)
               (if ($fx>= i 0)
-                  (if ($fx<= i ($port-output-size p))
-                      ($set-port-output-index! p i)
+                  (if ($fx<= i ($port-size p))
+                      ($set-port-index! p i)
                       (error 'set-port-output-index! "index ~s is too big" i))
                   (error 'set-port-output-index! "index ~s is negative" i))
               (error 'set-port-output-index! "~s is not a valid index" i))
@@ -178,10 +162,10 @@
       (if (output-port? p)
           (if (fixnum? i)
               (if ($fx>= i 0)
-                  (if ($fx<= i ($bytevector-length ($port-output-buffer p)))
+                  (if ($fx<= i ($bytevector-length ($port-buffer p)))
                       (begin
-                        ($set-port-output-index! p 0)
-                        ($set-port-output-size! p i))
+                        ($set-port-index! p 0)
+                        ($set-port-size! p i))
                       (error 'set-port-output-size! "size ~s is too big" i))
                   (error 'set-port-output-size! "size ~s is negative" i))
               (error 'set-port-output-size! "~s is not a valid size" i))
diff --git a/src/ikarus.io-primitives.unsafe.ss b/src/ikarus.io-primitives.unsafe.ss
index 037fde0..40f5267 100644
--- a/src/ikarus.io-primitives.unsafe.ss
+++ b/src/ikarus.io-primitives.unsafe.ss
@@ -42,10 +42,10 @@
   (define $write-byte
     (lambda (b p)
       (let ([idx (port-output-index p)])
-        (if ($fx< idx ($port-output-size p))
+        (if ($fx< idx ($port-size p))
             (begin
-              ($bytevector-set! ($port-output-buffer p) idx b)
-              ($set-port-output-index! p ($fxadd1 idx)))
+              ($bytevector-set! ($port-buffer p) idx b)
+              ($set-port-index! p ($fxadd1 idx)))
             (($port-handler p) 'write-byte b p)))))
 
   (define $read-char
diff --git a/src/ikarus.io.output-files.ss b/src/ikarus.io.output-files.ss
index 241f397..40d02e3 100644
--- a/src/ikarus.io.output-files.ss
+++ b/src/ikarus.io.output-files.ss
@@ -76,15 +76,15 @@
             [(write-byte b p)
              (if (and (fixnum? b) ($fx<= 0 b) ($fx<= b 255))
                  (if (output-port? p)
-                     (let ([idx ($port-output-index p)])
-                       (if ($fx< idx ($port-output-size p))
+                     (let ([idx ($port-index p)])
+                       (if ($fx< idx ($port-size p))
                            (begin
-                             ($bytevector-set! ($port-output-buffer p) idx b)
-                             ($set-port-output-index! p ($fxadd1 idx)))
+                             ($bytevector-set! ($port-buffer p) idx b)
+                             ($set-port-index! p ($fxadd1 idx)))
                            (if open?
                              (let ([bytes (do-write-buffer fd port-name
-                                             ($port-output-buffer p) idx 'write-char)])
-                               ($set-port-output-index! p 0)
+                                             ($port-buffer p) idx 'write-char)])
+                               ($set-port-index! p 0)
                                ($write-byte b p))
                              (error 'write-byte "port ~s is closed" p))))
                      (error 'write-byte "~s is not an output-port" p))
@@ -102,16 +102,16 @@
              (if (output-port? p)
                  (if open?
                      (let ([bytes (do-write-buffer fd port-name
-                                     ($port-output-buffer p) 
-                                     ($port-output-index p) 
+                                     ($port-buffer p) 
+                                     ($port-index p) 
                                      'flush-output-port)])
-                       ($set-port-output-index! p 0))
+                       ($set-port-index! p 0))
                      (error 'flush-output-port "port ~s is closed" p))
                  (error 'flush-output-port "~s is not an output-port" p))]
             [(close-port p)
              (when open?
                (flush-output-port p)
-               ($set-port-output-size! p 0)
+               ($set-port-size! p 0)
                (set! open? #f)
                (unless (foreign-call "ikrt_close_file" fd)
                  (error 'close-output-port "cannot close ~s" port-name)))]
diff --git a/src/ikarus.io.output-strings.ss b/src/ikarus.io.output-strings.ss
index 5643032..151afbe 100644
--- a/src/ikarus.io.output-strings.ss
+++ b/src/ikarus.io.output-strings.ss
@@ -112,16 +112,16 @@
             [(write-byte b p)
              (if (and (fixnum? b) ($fx<= 0 b) ($fx<= b 255))
                  (if (output-port? p)
-                     (let ([idx ($port-output-index p)])
-                       (if ($fx< idx ($port-output-size p))
+                     (let ([idx ($port-index p)])
+                       (if ($fx< idx ($port-size p))
                            (begin
-                             ($bytevector-set! ($port-output-buffer p) idx b)
-                             ($set-port-output-index! p ($fxadd1 idx)))
+                             ($bytevector-set! ($port-buffer p) idx b)
+                             ($set-port-index! p ($fxadd1 idx)))
                            (if open?
-                             (let ([buff ($port-output-buffer p)])
+                             (let ([buff ($port-buffer p)])
                                (set! buffer-list (cons (bv-copy buff) buffer-list))
                                ($bytevector-set! buff 0 b)
-                               ($set-port-output-index! p 1))
+                               ($set-port-index! p 1))
                              (error 'write-byte "port ~s is closed" p))))
                      (error 'write-byte "~s is not an output-port" p))
                  (error 'write-byte "~s is not a byte" b))]
@@ -142,8 +142,8 @@
             [(get-output-string p) 
              (utf8-bytevector->string
                (concat 
-                 ($port-output-buffer p) 
-                 ($port-output-index p)
+                 ($port-buffer p) 
+                 ($port-index p)
                  buffer-list))]
             [else (error 'output-handler 
                          "unhandled message ~s" (cons msg args))])))
diff --git a/src/makefile.ss b/src/makefile.ss
index dfc2dc6..26619dd 100755
--- a/src/makefile.ss
+++ b/src/makefile.ss
@@ -699,13 +699,6 @@
     [$set-port-index!         $ports]
     [$set-port-size!          $ports]
     
-    [$port-output-buffer      $ports]
-    [$port-output-index       $ports]
-    [$port-output-size        $ports]
-    [$set-port-output-index!  $ports]
-    [$set-port-output-size!   $ports]
-
-
     [$closure-code            $codes]
     [$code->closure           $codes]
     [$code-reloc-vector       $codes]
diff --git a/src/pass-specify-rep-primops.ss b/src/pass-specify-rep-primops.ss
index 335ad84..396c5e0 100644
--- a/src/pass-specify-rep-primops.ss
+++ b/src/pass-specify-rep-primops.ss
@@ -1421,27 +1421,25 @@
   [(P x) (sec-tag-test (T x) vector-mask vector-tag #f output-port-tag)]
   [(E x) (nop)])
 
-(define (make-port handler buf/i idx/i sz/i buf/o idx/o sz/o tag)
+(define (make-port handler buf/i idx/i sz/i tag)
   (with-tmp ([p (prm 'alloc (K (align port-size)) (K vector-tag))])
     (prm 'mset p (K (- vector-tag)) (K tag))
     (prm 'mset p (K (- disp-port-buffer vector-tag)) (T buf/i))
     (prm 'mset p (K (- disp-port-index vector-tag)) (T idx/i))
     (prm 'mset p (K (- disp-port-size vector-tag)) (T sz/i))
     (prm 'mset p (K (- disp-port-handler vector-tag)) (T handler))
-    (prm 'mset p (K (- disp-port-output-buffer vector-tag)) (T buf/o))
-    (prm 'mset p (K (- disp-port-output-index vector-tag)) (T idx/o))
-    (prm 'mset p (K (- disp-port-output-size vector-tag)) (T sz/o))
+    (prm 'mset p (K (- disp-port-unused1 vector-tag)) (K 0))
+    (prm 'mset p (K (- disp-port-unused2 vector-tag)) (K 0))
+    (prm 'mset p (K (- disp-port-unused3 vector-tag)) (K 0))
     p))
 
 (define-primop $make-port/input unsafe
-  [(V handler buf/i idx/i sz/i buf/o idx/o sz/o) 
-   (make-port handler buf/i idx/i sz/i buf/o idx/o sz/o
-              input-port-tag)])
+  [(V handler buf/i idx/i sz/i) 
+   (make-port handler buf/i idx/i sz/i input-port-tag)])
 
 (define-primop $make-port/output unsafe
-  [(V handler buf/i idx/i sz/i buf/o idx/o sz/o) 
-   (make-port handler buf/i idx/i sz/i buf/o idx/o sz/o
-              output-port-tag)])
+  [(V handler buf/o idx/o sz/o) 
+   (make-port handler buf/o idx/o sz/o output-port-tag)])
 
 (define-primop $port-handler unsafe
   [(V x) (prm 'mref (T x) (K (- disp-port-handler vector-tag)))])
@@ -1459,20 +1457,6 @@
      (prm 'mset (T x) (K (- disp-port-index vector-tag)) (K 0))
      (prm 'mset (T x) (K (- disp-port-size vector-tag)) (T i)))])
 
-(define-primop $port-output-buffer unsafe
-  [(V x) (prm 'mref (T x) (K (- disp-port-output-buffer vector-tag)))])
-(define-primop $port-output-index unsafe
-  [(V x) (prm 'mref (T x) (K (- disp-port-output-index vector-tag)))])
-(define-primop $port-output-size unsafe
-  [(V x) (prm 'mref (T x) (K (- disp-port-output-size vector-tag)))])
-(define-primop $set-port-output-index! unsafe
-  [(E x i) (prm 'mset (T x) (K (- disp-port-output-index vector-tag)) (T i))])
-(define-primop $set-port-output-size! unsafe
-  [(E x i) 
-   (seq*
-     (prm 'mset (T x) (K (- disp-port-output-index vector-tag)) (K 0))
-     (prm 'mset (T x) (K (- disp-port-output-size vector-tag)) (T i)))])
-
 /section)
 
 (section ;;; interrupts-and-engines