diff --git a/src/mzscheme/include/scheme.h b/src/mzscheme/include/scheme.h
index 5bf93ff423..6909da0b4f 100644
--- a/src/mzscheme/include/scheme.h
+++ b/src/mzscheme/include/scheme.h
@@ -583,6 +583,7 @@ typedef void (*Scheme_Type_Printer)(Scheme_Object *v, int for_display, Scheme_Pr
 #define SCHEME_PRIM_IS_CLOSURE 4096
 #define SCHEME_PRIM_IS_NONCM 8192
 #define SCHEME_PRIM_IS_UNARY_INLINED 16384
+#define SCHEME_PRIM_IS_MIN_NARY_INLINED 32768
 
 #define SCHEME_PRIM_STRUCT_TYPE_INDEXLESS_GETTER 0
 #define SCHEME_PRIM_STRUCT_TYPE_CONSTR 64
diff --git a/src/mzscheme/src/eval.c b/src/mzscheme/src/eval.c
index 70bc8d5df1..899c8b84ad 100644
--- a/src/mzscheme/src/eval.c
+++ b/src/mzscheme/src/eval.c
@@ -1023,6 +1023,10 @@ static int eq_testable_constant(Scheme_Object *v)
       || SAME_OBJ(v, scheme_true)
       || SCHEME_VOIDP(v))
     return 1;
+
+  if (SCHEME_CHARP(v) && (SCHEME_CHAR_VAL(v) < 256))
+    return 1;
+
   return 0;
 }
 
diff --git a/src/mzscheme/src/jit.c b/src/mzscheme/src/jit.c
index 947b6b6091..c550954a36 100644
--- a/src/mzscheme/src/jit.c
+++ b/src/mzscheme/src/jit.c
@@ -1013,8 +1013,7 @@ static int inlined_binary_prim(Scheme_Object *o, Scheme_Object *_app)
 static int inlined_nary_prim(Scheme_Object *o, Scheme_Object *_app)
 {
   return (SCHEME_PRIMP(o)
-	  && ((SCHEME_PRIM_PROC_FLAGS(o) & (SCHEME_PRIM_IS_UNARY_INLINED | SCHEME_PRIM_IS_BINARY_INLINED))
-	      == (SCHEME_PRIM_IS_UNARY_INLINED | SCHEME_PRIM_IS_BINARY_INLINED))
+	  && (SCHEME_PRIM_PROC_FLAGS(o) & SCHEME_PRIM_IS_MIN_NARY_INLINED)
 	  && (((Scheme_App_Rec *)_app)->num_args == ((Scheme_Primitive_Proc *)o)->mina));
 }
 
@@ -2665,8 +2664,7 @@ static int generate_inlined_nary(mz_jit_state *jitter, Scheme_App_Rec *app, int
   if (!SCHEME_PRIMP(rator))
     return 0;
 
-  if ((SCHEME_PRIM_PROC_FLAGS(rator) & (SCHEME_PRIM_IS_UNARY_INLINED | SCHEME_PRIM_IS_BINARY_INLINED))
-      != (SCHEME_PRIM_IS_UNARY_INLINED | SCHEME_PRIM_IS_BINARY_INLINED))
+  if (!(SCHEME_PRIM_PROC_FLAGS(rator) & SCHEME_PRIM_IS_MIN_NARY_INLINED))
     return 0;
 
   if (app->num_args != ((Scheme_Primitive_Proc *)rator)->mina)
diff --git a/src/mzscheme/src/module.c b/src/mzscheme/src/module.c
index 9cfbd8976d..db515d2851 100644
--- a/src/mzscheme/src/module.c
+++ b/src/mzscheme/src/module.c
@@ -992,7 +992,7 @@ static Scheme_Object *namespace_attach_module(int argc, Scheme_Object *argv[])
   Scheme_Hash_Table *checked, *next_checked, *prev_checked;
   Scheme_Object *past_checkeds, *future_checkeds, *future_todos, *past_to_modchains;
   Scheme_Module *m2;
-  int same_namespace, skip_notify = 0, phase;
+  int same_namespace, set_env_for_notify = 0, phase;
 
   if (!SCHEME_NAMESPACEP(argv[0]))
     scheme_wrong_type("namespace-attach-module", "namespace", 0, argc, argv);
@@ -1004,7 +1004,7 @@ static Scheme_Object *namespace_attach_module(int argc, Scheme_Object *argv[])
     if (!SCHEME_NAMESPACEP(argv[2]))
       scheme_wrong_type("namespace-attach-module", "namespace", 2, argc, argv);
     to_env = (Scheme_Env *)argv[2];
-    skip_notify = 1;
+    set_env_for_notify = 1;
   } else
     to_env = scheme_get_env(NULL);
 
@@ -1274,9 +1274,23 @@ static Scheme_Object *namespace_attach_module(int argc, Scheme_Object *argv[])
        #f for to_modchain if there's more to do. */
   }
 
-  if (!skip_notify) {
-    /* Notify module name resolver of attached modules: */
-    resolver = scheme_get_param(scheme_current_config(), MZCONFIG_CURRENT_MODULE_RESOLVER);
+  /* Notify module name resolver of attached modules: */
+  {
+    Scheme_Cont_Frame_Data cframe;
+    Scheme_Config *config;
+
+    config = scheme_current_config();
+    
+    if (set_env_for_notify) {
+      config = scheme_extend_config(scheme_current_config(),
+				    MZCONFIG_ENV,
+				    (Scheme_Object *)to_env);
+  
+      scheme_push_continuation_frame(&cframe);
+      scheme_set_cont_mark(scheme_parameterization_key, (Scheme_Object *)config);
+    }
+
+    resolver = scheme_get_param(config, MZCONFIG_CURRENT_MODULE_RESOLVER);
     while (!SCHEME_NULLP(notifies)) {
       a[0] = scheme_false;
       a[1] = SCHEME_CAR(notifies);
@@ -1286,6 +1300,10 @@ static Scheme_Object *namespace_attach_module(int argc, Scheme_Object *argv[])
       
       notifies = SCHEME_CDR(notifies);
     }
+
+    if (set_env_for_notify) {
+      scheme_pop_continuation_frame(&cframe);
+    }
   }
 
   return scheme_void;
diff --git a/src/mzscheme/src/numstr.c b/src/mzscheme/src/numstr.c
index 4729bed989..aceaebd68c 100644
--- a/src/mzscheme/src/numstr.c
+++ b/src/mzscheme/src/numstr.c
@@ -1367,6 +1367,34 @@ number_to_string (int argc, Scheme_Object *argv[])
   } else
     radix = 10;
 
+  if (SCHEME_INTP(o) && ((radix == 10) || (radix == 16))) {
+    /* Fast path for common case. */
+    mzchar num[32];
+    int pos = 32;
+    long v = SCHEME_INT_VAL(o);
+    if (v) {
+      int neg, digit;
+      if (v < 0) {
+	neg = 1;
+	v = -v;
+      } else
+	neg = 0;
+      while (v) {
+	digit = (v % radix);
+	if (digit < 10)
+	  num[--pos] = digit + '0';
+	else
+	  num[--pos] = (digit - 10) + 'a';
+	v = v / radix;
+      }
+      if (neg)
+	num[--pos] = '-';
+    } else {
+      num[--pos] = '0';
+    }
+    return scheme_make_sized_offset_char_string(num, pos, 32 - pos, 1);
+  }
+
   return scheme_make_utf8_string/*_without_copying*/(number_to_allocated_string(radix, o, 1));
 }
 
@@ -1476,7 +1504,7 @@ static char *double_to_string (double d, int alloc)
   return s;
 }
 
-char *number_to_allocated_string(int radix, Scheme_Object *obj, int alloc)
+static char *number_to_allocated_string(int radix, Scheme_Object *obj, int alloc)
 {
   char *s;
 
diff --git a/src/mzscheme/src/port.c b/src/mzscheme/src/port.c
index b56f1320d0..e19c062ce3 100644
--- a/src/mzscheme/src/port.c
+++ b/src/mzscheme/src/port.c
@@ -1337,6 +1337,9 @@ long scheme_get_byte_string_unless(const char *who,
   Scheme_Get_String_Fun gs;
   Scheme_Peek_String_Fun ps;
 
+  /* See also get_one_byte, below. Any change to this function
+     may require a change to 1-byte specialization of get_one_byte. */
+
   /* back-door argument: */
   special_is_ok = 0;
 
@@ -1434,8 +1437,11 @@ long scheme_get_byte_string_unless(const char *who,
 
     if (check_special && ip->ungotten_special) {
       if (!special_ok) {
-	if (!peek && ip->progress_evt)
-	  post_progress(ip);
+	if (!peek) {
+	  if (ip->progress_evt)
+	    post_progress(ip);
+	  ip->ungotten_special = NULL;
+	}
 	scheme_bad_time_for_special(who, port);
       }
       if (!peek) {
@@ -2240,6 +2246,103 @@ long scheme_get_char_string(const char *who,
   }
 }
 
+static 
+#ifndef NO_INLINE_KEYWORD
+MSC_IZE(inline)
+#endif
+long get_one_byte(const char *who,
+		  Scheme_Object *port,
+		  char *buffer, long offset,
+		  int only_avail)
+{
+  Scheme_Input_Port *ip;
+  long gc;
+  int special_ok = special_is_ok;
+  Scheme_Get_String_Fun gs;
+
+  special_is_ok = 0;
+
+  ip = (Scheme_Input_Port *)port;
+
+  CHECK_PORT_CLOSED(who, "input", port, ip->closed);
+
+  if (ip->input_lock)
+    scheme_wait_input_allowed(ip, only_avail);
+
+  if (ip->ungotten_count) {
+    buffer[offset] = ip->ungotten[--ip->ungotten_count];
+    gc = 1;
+  } else if (ip->peeked_read && pipe_char_count(ip->peeked_read)) {
+    int ch;
+    ch = scheme_get_byte(ip->peeked_read);
+    buffer[offset] = ch;
+    gc = 1;
+  } else if (ip->ungotten_special) {
+    if (ip->progress_evt)
+      post_progress(ip);
+    if (!special_ok) {
+      ip->ungotten_special = NULL;
+      scheme_bad_time_for_special(who, port);
+      return 0;
+    }
+    ip->special = ip->ungotten_special;
+    ip->ungotten_special = NULL;
+    if (ip->p.position >= 0)
+      ip->p.position++;
+    if (ip->p.count_lines)
+      inc_pos((Scheme_Port *)ip, 1);
+    return SCHEME_SPECIAL;
+  } else {
+    if (ip->pending_eof > 1) {
+      ip->pending_eof = 1;
+      return EOF;
+    } else {
+      /* Call port's get function. */
+      gs = ip->get_string_fun;
+
+      gc = gs(ip, buffer, offset, 1, 0, NULL);
+	
+      if (ip->progress_evt && (gc > 0))
+	post_progress(ip);
+
+      if (gc < 1) {
+	if (gc == SCHEME_SPECIAL) {
+	  if (special_ok) {
+	    if (ip->p.position >= 0)
+	      ip->p.position++;
+	    if (ip->p.count_lines)
+	      inc_pos((Scheme_Port *)ip, 1);
+	    return SCHEME_SPECIAL;
+	  } else {
+	    scheme_bad_time_for_special(who, port);
+	    return 0;
+	  }
+	} else if (gc == EOF) {
+	  ip->p.utf8state = 0;
+	  return EOF;
+	} else {
+	  /* didn't get anything the first try, so use slow path: */
+	  special_is_ok = special_ok;
+	  return scheme_get_byte_string_unless(who, port,
+					       buffer, offset, 1,
+					       0, 0, NULL, NULL);
+	}
+      }
+    }
+  }
+
+  /****************************************************/
+  /* Adjust position information for chars got so far */
+  /****************************************************/
+  
+  if (ip->p.position >= 0)
+    ip->p.position++;
+  if (ip->p.count_lines)
+    do_count_lines((Scheme_Port *)ip, buffer, offset, 1);
+  
+  return gc;
+}
+
 int
 scheme_getc(Scheme_Object *port)
 {
@@ -2248,11 +2351,18 @@ scheme_getc(Scheme_Object *port)
   int v, delta = 0;
 
   while(1) {
-    v = scheme_get_byte_string_unless("read-char", port,
-				      s, delta, 1,
-				      0,
-				      delta > 0, scheme_make_integer(delta-1),
-				      NULL);
+    if (delta) {
+      v = scheme_get_byte_string_unless("read-char", port,
+					s, delta, 1,
+					0,
+					delta > 0, scheme_make_integer(delta-1),
+					NULL);
+    } else {
+      v = get_one_byte("read-char", port,
+		       s, 0, 
+		       0);
+    }
+
     if ((v == EOF) || (v == SCHEME_SPECIAL)) {
       if (!delta)
 	return v;
@@ -2290,11 +2400,9 @@ scheme_get_byte(Scheme_Object *port)
   char s[1];
   int v;
 
-  v = scheme_get_byte_string_unless("read-byte", port,
-				    s, 0, 1,
-				    0,
-				    0, 0,
-				    NULL);
+  v = get_one_byte("read-byte", port,
+		   s, 0,
+		   0);
 
   if ((v == EOF) || (v == SCHEME_SPECIAL))
     return v;
@@ -4487,21 +4595,27 @@ static long fd_get_string(Scheme_Input_Port *port,
   Scheme_FD *fip;
   long bc;
 
-  if (scheme_unless_ready(unless))
+  if (unless && scheme_unless_ready(unless))
     return SCHEME_UNLESS_READY;
 
   fip = (Scheme_FD *)port->port_data;
 
   if (fip->bufcount) {
-    bc = ((size <= fip->bufcount)
-	  ? size
-	  : fip->bufcount);
+    if (size == 1) {
+      buffer[offset] = fip->buffer[fip->buffpos++];
+      --fip->bufcount;
+      return 1;
+    } else {
+      bc = ((size <= fip->bufcount)
+	    ? size
+	    : fip->bufcount);
 
-    memcpy(buffer + offset, fip->buffer + fip->buffpos, bc);
-    fip->buffpos += bc;
-    fip->bufcount -= bc;
+      memcpy(buffer + offset, fip->buffer + fip->buffpos, bc);
+      fip->buffpos += bc;
+      fip->bufcount -= bc;
 
-    return bc;
+      return bc;
+    }
   } else {
     if ((nonblock == 2) && (fip->flush == MZ_FLUSH_ALWAYS))
       return 0;
diff --git a/src/mzscheme/src/portfun.c b/src/mzscheme/src/portfun.c
index 602f23fdb8..185b0b2109 100644
--- a/src/mzscheme/src/portfun.c
+++ b/src/mzscheme/src/portfun.c
@@ -771,7 +771,14 @@ string_get_or_peek_bytes(Scheme_Input_Port *port,
   is = (Scheme_Indexed_String *) port->port_data;
   if (is->index + skip >= is->size)
     return EOF;
-  else {
+  else if (size == 1) {
+    int pos = is->index;
+    if (buffer)
+      buffer[offset] = is->string[pos + skip];
+    if (!peek)
+      is->index = pos + 1;
+    return 1;
+  } else {
     long l, delta;
 
     delta = is->index + skip;
diff --git a/src/mzscheme/src/string.c b/src/mzscheme/src/string.c
index 8c4fcf5095..4a557b4947 100644
--- a/src/mzscheme/src/string.c
+++ b/src/mzscheme/src/string.c
@@ -369,8 +369,7 @@ scheme_init_string (Scheme_Env *env)
 
 
   p = scheme_make_noncm_prim(scheme_checked_string_set, "string-set!", 3, 3);
-  SCHEME_PRIM_PROC_FLAGS(p) |= (SCHEME_PRIM_IS_UNARY_INLINED
-				| SCHEME_PRIM_IS_BINARY_INLINED);
+  SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_MIN_NARY_INLINED;
   scheme_add_global_constant("string-set!", p, env);
 
   scheme_add_global_constant("string=?",
@@ -614,7 +613,7 @@ scheme_init_string (Scheme_Env *env)
 			     env);
 
   p = scheme_make_folding_prim(byte_string_p, "bytes?", 1, 1, 1);
-  SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_UNARY_INLINED;
+  SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_MIN_NARY_INLINED;
   scheme_add_global_constant("bytes?", p, env);
 
   scheme_add_global_constant("make-bytes",
@@ -638,8 +637,7 @@ scheme_init_string (Scheme_Env *env)
   scheme_add_global_constant("bytes-ref", p, env);
 
   p = scheme_make_noncm_prim(scheme_checked_byte_string_set, "bytes-set!", 3, 3);
-  SCHEME_PRIM_PROC_FLAGS(p) |= (SCHEME_PRIM_IS_UNARY_INLINED
-				| SCHEME_PRIM_IS_BINARY_INLINED);
+  SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_MIN_NARY_INLINED;
   scheme_add_global_constant("bytes-set!", p, env);
 
   scheme_add_global_constant("bytes=?",
diff --git a/src/mzscheme/src/vector.c b/src/mzscheme/src/vector.c
index d1297a1031..acd6c8da45 100644
--- a/src/mzscheme/src/vector.c
+++ b/src/mzscheme/src/vector.c
@@ -82,8 +82,7 @@ scheme_init_vector (Scheme_Env *env)
   p = scheme_make_noncm_prim(scheme_checked_vector_set,
 			     "vector-set!", 
 			     3, 3);
-  SCHEME_PRIM_PROC_FLAGS(p) |= (SCHEME_PRIM_IS_UNARY_INLINED
-				| SCHEME_PRIM_IS_BINARY_INLINED);
+  SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_MIN_NARY_INLINED;
   scheme_add_global_constant("vector-set!", p, env);
 
   scheme_add_global_constant("vector->list",