diff --git a/lab/io-prims.ss b/lab/io-prims.ss
index aea794a..58a6bdf 100644
--- a/lab/io-prims.ss
+++ b/lab/io-prims.ss
@@ -5,4 +5,5 @@
     (io-spec)  
     (except (ikarus)))
 
+
   )
diff --git a/lab/io-spec.ss b/lab/io-spec.ss
index de78074..1f0cd9d 100644
--- a/lab/io-spec.ss
+++ b/lab/io-spec.ss
@@ -2,10 +2,171 @@
 (library (io-spec) 
   (export )
   (import 
-    (except (ikarus) ))
+    (except (ikarus) get-char get-u8 put-char put-u8))
 
   (define-struct $port 
-    (buffer index size handlers codec attrs))
+    (index size buffer base-index codec closed? handlers attrs))
+  (define $set-port-index! set-$port-index!)
 
+  (define fast-get-tag          #x0001)
+  (define fast-put-tag         #x0002)
+  (define fast-get-position-tag  #x0004)
+
+  (define fast-get-mask         #x00F0)
+  (define fast-get-utf8-tag     #x0010)
+  (define fast-get-latin-tag    #x0030)
+  (define fast-get-byte-tag     #x0040)
+  (define fast-get-char-tag     #x0080)
+
+  (define fast-put-mask        #x0F00)
+  (define fast-put-utf8-tag    #x0100)
+  (define fast-put-latin-tag   #x0300)
+  (define fast-put-byte-tag    #x0400)
+  (define fast-put-char-tag    #x0800)
   
+  (define r6rs-mode-tag          #x1000)
+
+  (define ($port-get-mode x)
+    (and ($port? x) (fxand ($port-attrs x) fast-get-mask)))
+
+  (define ($port-put-mode x)
+    (and ($port? x) (fxand ($port-attrs x) fast-put-mask)))
+
+  (define (u8? x)
+    (and (fixnum? x) (fx>= x 0) (fx< x 256)))
+
+  ;;; everything above this line will turn into primitive
+  ;;; ----------------------------------------------------------
+  
+  (define-struct handler
+    (data id read! write! get-position set-position! close))
+
+  (define-syntax define-rrr
+    (syntax-rules ()
+      [(_ name)
+       (define (name . args) 
+         (error 'name "not implemented" args))]))
+
+  ;;; ----------------------------------------------------------
+  (module (get-char)
+    (define-rrr get-char-utf8-mode)
+    (define-rrr get-char-latin-mode)
+    (define-rrr get-char-char-mode)
+    (define-rrr slow-get-char)
+    ;;;
+    (define (get-char p)
+      (define who 'get-char)
+      (let ([m ($port-get-mode p)])
+        (cond
+          [(eq? m fast-get-utf8-tag)
+           (let ([i ($port-index p)])
+             (cond
+               [(fx< i ($port-size p))
+                (let ([b (bytevector-u8-ref ($port-buffer p) i)])
+                  (cond
+                    [(fx< b 128) 
+                     ($set-port-index! p (fx+ i 1))
+                     (integer->char b)]
+                    [else (get-char-utf8-mode p)]))]
+               [else
+                (get-char-utf8-mode p who)]))]
+          [(eq? m fast-get-char-tag)
+           (let ([i ($port-index p)])
+             (cond
+               [(fx< i ($port-size p))
+                ($set-port-index! p (fx+ i 1))
+                (string-ref ($port-buffer p) i)]
+               [else
+                (get-char-char-mode p who)]))]
+          [(eq? m fast-get-latin-tag)
+           (let ([i ($port-index p)])
+             (cond
+               [(fx< i ($port-size p))
+                ($set-port-index! p (fx+ i 1))
+                (integer->char 
+                  (bytevector-u8-ref ($port-buffer p) i))]
+               [else
+                (get-char-latin-mode p who)]))]
+          [else (slow-get-char p who)]))))
+
+  ;;; ----------------------------------------------------------
+  (module (get-u8)
+    (define-rrr get-u8-byte-mode)
+    (define-rrr slow-get-u8)
+    ;;;
+    (define (get-u8 p)
+      (define who 'get-u8)
+      (let ([m ($port-get-mode p)])
+        (cond
+          [(eq? m fast-get-byte-tag)
+           (let ([i ($port-index p)])
+             (cond
+               [(fx< i ($port-size p))
+                ($set-port-index! p (fx+ i 1))
+                (bytevector-u8-ref ($port-buffer p) i)]
+               [else (get-u8-byte-mode p who)]))]
+          [else (slow-get-u8 p who)]))))
+
+  ;;; ----------------------------------------------------------
+  (module (put-char)
+    (define-rrr put-char-utf8-mode)
+    (define-rrr put-char-latin-mode)
+    (define-rrr put-char-char-mode)
+    (define-rrr slow-put-char)
+    ;;;
+    (define (put-char p c)
+      (define who 'put-char)
+      (unless (char? c) (error who "not a char" c))
+      (let ([m ($port-put-mode p)])
+        (cond
+          [(eq? m fast-put-utf8-tag)
+           (let ([i ($port-index p)])
+             (let ([b (char->integer c)])
+               (cond
+                 [(and (fx< i ($port-size p)) (fx< b 128))
+                  ($set-port-index! p (fx+ i 1))
+                  (bytevector-u8-set! ($port-buffer p) i b)]
+                 [else
+                  (put-char-utf8-mode p b who)])))]
+          [(eq? m fast-put-char-tag)
+           (let ([i ($port-index p)])
+             (cond
+               [(fx< i ($port-size p))
+                ($set-port-index! p (fx+ i 1))
+                (string-set! ($port-buffer p) i c)]
+               [else
+                (put-char-char-mode p c who)]))]
+          [(eq? m fast-put-latin-tag)
+           (let ([i ($port-index p)])
+             (let ([b (char->integer c)])
+               (cond
+                 [(and (fx< i ($port-size p)) (fx< b 256))
+                  ($set-port-index! p (fx+ i 1))
+                  (bytevector-u8-set! ($port-buffer p) i b)]
+                 [else
+                  (put-char-latin-mode p b who)])))]
+          [else (slow-put-char p c who)]))))
+
+  ;;; ----------------------------------------------------------
+  (module (put-u8)
+    (define-rrr put-u8-byte-mode)
+    (define-rrr slow-put-u8)
+    ;;;
+    (define (put-u8 p b)
+      (define who 'put-u8)
+      (unless (u8? b) (error who "not a u8" b))
+      (let ([m ($port-put-mode p)])
+        (cond
+          [(eq? m fast-put-byte-tag)
+           (let ([i ($port-index p)])
+             (cond
+               [(fx< i ($port-size p))
+                ($set-port-index! p (fx+ i 1))
+                (bytevector-u8-set! ($port-buffer p) i b)]
+               [else
+                (put-u8-byte-mode p b who)]))]
+          [else (slow-put-u8 p b who)]))))
+
+  ;;; that's it for today.  see you tomorrow .
+
   )
diff --git a/lab/test-io.ss b/lab/test-io.ss
index 6cee7e9..c00f394 100755
--- a/lab/test-io.ss
+++ b/lab/test-io.ss
@@ -2,5 +2,5 @@
 
 (import 
   (except (ikarus))
-  (io-prims))
+  (io-spec))