diff --git a/basis/bootstrap/image/image.factor b/basis/bootstrap/image/image.factor
index e086215e91..711f2f36f3 100644
--- a/basis/bootstrap/image/image.factor
+++ b/basis/bootstrap/image/image.factor
@@ -218,8 +218,12 @@ USERENV: undefined-quot 60
 
 : here-as ( tag -- pointer ) here bitor ;
 
+: (align-here) ( alignment -- )
+    [ here neg ] dip rem
+    [ bootstrap-cell /i [ 0 emit ] times ] unless-zero ;
+
 : align-here ( -- )
-    here 8 mod 4 = [ 0 emit ] when ;
+    data-alignment get (align-here) ;
 
 : emit-fixnum ( n -- ) tag-fixnum emit ;
 
@@ -293,7 +297,7 @@ M: fake-bignum ' n>> tag-fixnum ;
 M: float '
     [
         float [
-            align-here double>bits emit-64
+            8 (align-here) double>bits emit-64
         ] emit-object
     ] cache-eql-object ;
 
@@ -411,6 +415,7 @@ M: byte-array '
     [
         byte-array [
             dup length emit-fixnum
+            bootstrap-cell 4 = [ 0 emit 0 emit ] when
             pad-bytes emit-bytes
         ] emit-object
     ] cache-eq-object ;
diff --git a/basis/compiler/constants/constants.factor b/basis/compiler/constants/constants.factor
index a22d522809..ab607d2178 100644
--- a/basis/compiler/constants/constants.factor
+++ b/basis/compiler/constants/constants.factor
@@ -17,7 +17,7 @@ CONSTANT: deck-bits 18
 : string-offset ( -- n ) 4 string tag-number slot-offset ; inline
 : string-aux-offset ( -- n ) 2 string tag-number slot-offset ; inline
 : profile-count-offset ( -- n ) 8 \ word tag-number slot-offset ; inline
-: byte-array-offset ( -- n ) 2 byte-array tag-number slot-offset ; inline
+: byte-array-offset ( -- n ) 16 byte-array tag-number - ; inline
 : alien-offset ( -- n ) 3 alien tag-number slot-offset ; inline
 : underlying-alien-offset ( -- n ) 1 alien tag-number slot-offset ; inline
 : tuple-class-offset ( -- n ) 1 tuple tag-number slot-offset ; inline
diff --git a/basis/cpu/ppc/ppc.factor b/basis/cpu/ppc/ppc.factor
index 517aa7587d..7226145c27 100644
--- a/basis/cpu/ppc/ppc.factor
+++ b/basis/cpu/ppc/ppc.factor
@@ -374,7 +374,7 @@ M: ppc %set-alien-double -rot STFD ;
     [ drop load-zone-ptr ] [ swap 0 LWZ ] 2bi ;
 
 :: inc-allot-ptr ( nursery-ptr allot-ptr n -- )
-    scratch-reg allot-ptr n 8 align ADDI
+    scratch-reg allot-ptr n data-alignment get align ADDI
     scratch-reg nursery-ptr 0 STW ;
 
 :: store-header ( dst class -- )
diff --git a/basis/cpu/x86/x86.factor b/basis/cpu/x86/x86.factor
index 4576956335..e061ea5d95 100644
--- a/basis/cpu/x86/x86.factor
+++ b/basis/cpu/x86/x86.factor
@@ -388,7 +388,7 @@ M: x86 %vm-field-ptr ( dst field -- )
     [ drop "nursery" %vm-field-ptr ] [ swap [] MOV ] 2bi ;
 
 : inc-allot-ptr ( nursery-ptr n -- )
-    [ [] ] dip 8 align ADD ;
+    [ [] ] dip data-alignment get align ADD ;
 
 : store-header ( temp class -- )
     [ [] ] [ type-number tag-fixnum ] bi* MOV ;
diff --git a/core/bootstrap/layouts/layouts.factor b/core/bootstrap/layouts/layouts.factor
index 5ed92b7776..fef7ba2a83 100644
--- a/core/bootstrap/layouts/layouts.factor
+++ b/core/bootstrap/layouts/layouts.factor
@@ -5,6 +5,8 @@ hashtables vectors strings sbufs arrays
 quotations assocs layouts classes.tuple.private
 kernel.private ;
 
+16 data-alignment set
+
 BIN: 111 tag-mask set
 8 num-tags set
 3 tag-bits set
diff --git a/core/layouts/layouts.factor b/core/layouts/layouts.factor
index be6276a684..2f0fa12d44 100644
--- a/core/layouts/layouts.factor
+++ b/core/layouts/layouts.factor
@@ -4,6 +4,8 @@ USING: namespaces math words kernel assocs classes
 math.order kernel.private ;
 IN: layouts
 
+SYMBOL: data-alignment
+
 SYMBOL: tag-mask
 
 SYMBOL: num-tags
diff --git a/vm/arrays.cpp b/vm/arrays.cpp
index 09c6998e69..3af8b0600b 100644
--- a/vm/arrays.cpp
+++ b/vm/arrays.cpp
@@ -7,7 +7,7 @@ namespace factor
 array *factor_vm::allot_array(cell capacity, cell fill_)
 {
 	gc_root<object> fill(fill_,this);
-	gc_root<array> new_array(allot_array_internal<array>(capacity),this);
+	gc_root<array> new_array(allot_uninitialized_array<array>(capacity),this);
 
 	if(fill.value() == tag_fixnum(0))
 		memset(new_array->data(),'\0',capacity * sizeof(cell));
@@ -33,7 +33,7 @@ void factor_vm::primitive_array()
 cell factor_vm::allot_array_1(cell obj_)
 {
 	gc_root<object> obj(obj_,this);
-	gc_root<array> a(allot_array_internal<array>(1),this);
+	gc_root<array> a(allot_uninitialized_array<array>(1),this);
 	set_array_nth(a.untagged(),0,obj.value());
 	return a.value();
 }
@@ -42,7 +42,7 @@ cell factor_vm::allot_array_2(cell v1_, cell v2_)
 {
 	gc_root<object> v1(v1_,this);
 	gc_root<object> v2(v2_,this);
-	gc_root<array> a(allot_array_internal<array>(2),this);
+	gc_root<array> a(allot_uninitialized_array<array>(2),this);
 	set_array_nth(a.untagged(),0,v1.value());
 	set_array_nth(a.untagged(),1,v2.value());
 	return a.value();
@@ -54,7 +54,7 @@ cell factor_vm::allot_array_4(cell v1_, cell v2_, cell v3_, cell v4_)
 	gc_root<object> v2(v2_,this);
 	gc_root<object> v3(v3_,this);
 	gc_root<object> v4(v4_,this);
-	gc_root<array> a(allot_array_internal<array>(4),this);
+	gc_root<array> a(allot_uninitialized_array<array>(4),this);
 	set_array_nth(a.untagged(),0,v1.value());
 	set_array_nth(a.untagged(),1,v2.value());
 	set_array_nth(a.untagged(),2,v3.value());
diff --git a/vm/bignum.cpp b/vm/bignum.cpp
index d8c5452b08..5a391e7625 100755
--- a/vm/bignum.cpp
+++ b/vm/bignum.cpp
@@ -1299,7 +1299,7 @@ bignum *factor_vm::bignum_digit_to_bignum(bignum_digit_type digit, int negative_
 bignum *factor_vm::allot_bignum(bignum_length_type length, int negative_p)
 {
 	BIGNUM_ASSERT ((length >= 0) || (length < BIGNUM_RADIX));
-	bignum * result = allot_array_internal<bignum>(length + 1);
+	bignum * result = allot_uninitialized_array<bignum>(length + 1);
 	BIGNUM_SET_NEGATIVE_P (result, negative_p);
 	return (result);
 }
diff --git a/vm/byte_arrays.cpp b/vm/byte_arrays.cpp
index 56b5db7ad8..fa02ede6c3 100644
--- a/vm/byte_arrays.cpp
+++ b/vm/byte_arrays.cpp
@@ -5,7 +5,7 @@ namespace factor
 
 byte_array *factor_vm::allot_byte_array(cell size)
 {
-	byte_array *array = allot_array_internal<byte_array>(size);
+	byte_array *array = allot_uninitialized_array<byte_array>(size);
 	memset(array + 1,0,size);
 	return array;
 }
@@ -19,7 +19,7 @@ void factor_vm::primitive_byte_array()
 void factor_vm::primitive_uninitialized_byte_array()
 {
 	cell size = unbox_array_size();
-	dpush(tag<byte_array>(allot_array_internal<byte_array>(size)));
+	dpush(tag<byte_array>(allot_uninitialized_array<byte_array>(size)));
 }
 
 void factor_vm::primitive_resize_byte_array()
diff --git a/vm/callbacks.cpp b/vm/callbacks.cpp
index dca0eb6c24..599271555b 100644
--- a/vm/callbacks.cpp
+++ b/vm/callbacks.cpp
@@ -39,14 +39,14 @@ callback *callback_heap::add(code_block *compiled)
 	tagged<byte_array> insns(array_nth(code_template.untagged(),0));
 	cell size = array_capacity(insns.untagged());
 
-	cell bump = align8(size) + sizeof(callback);
+	cell bump = align(size,sizeof(cell)) + sizeof(callback);
 	if(here + bump > seg->end) fatal_error("Out of callback space",0);
 
 	callback *stub = (callback *)here;
 	stub->compiled = compiled;
 	memcpy(stub + 1,insns->data<void>(),size);
 
-	stub->size = align8(size);
+	stub->size = align(size,sizeof(cell));
 	here += bump;
 
 	update(stub);
diff --git a/vm/contexts.cpp b/vm/contexts.cpp
index cc7029e7f1..ce52555a21 100644
--- a/vm/contexts.cpp
+++ b/vm/contexts.cpp
@@ -133,7 +133,7 @@ bool factor_vm::stack_to_array(cell bottom, cell top)
 		return false;
 	else
 	{
-		array *a = allot_array_internal<array>(depth / sizeof(cell));
+		array *a = allot_uninitialized_array<array>(depth / sizeof(cell));
 		memcpy(a + 1,(void*)bottom,depth);
 		dpush(tag<array>(a));
 		return true;
diff --git a/vm/data_heap.cpp b/vm/data_heap.cpp
index 335938acab..05ce026973 100755
--- a/vm/data_heap.cpp
+++ b/vm/data_heap.cpp
@@ -119,7 +119,7 @@ cell factor_vm::object_size(cell tagged)
 /* Size of the object pointed to by an untagged pointer */
 cell factor_vm::untagged_object_size(object *pointer)
 {
-	return align8(unaligned_object_size(pointer));
+	return align(unaligned_object_size(pointer),data_alignment);
 }
 
 /* Size of the data area of an object pointed to by an untagged pointer */
diff --git a/vm/generic_arrays.hpp b/vm/generic_arrays.hpp
index 0ba6d11da2..e1d2c4dc0b 100755
--- a/vm/generic_arrays.hpp
+++ b/vm/generic_arrays.hpp
@@ -19,7 +19,7 @@ template<typename Array> cell array_size(Array *array)
 	return array_size<Array>(array_capacity(array));
 }
 
-template<typename Array> Array *factor_vm::allot_array_internal(cell capacity)
+template<typename Array> Array *factor_vm::allot_uninitialized_array(cell capacity)
 {
 	Array *array = allot<Array>(array_size<Array>(capacity));
 	array->capacity = tag_fixnum(capacity);
@@ -46,7 +46,7 @@ template<typename Array> Array *factor_vm::reallot_array(Array *array_, cell cap
 		if(capacity < to_copy)
 			to_copy = capacity;
 
-		Array *new_array = allot_array_internal<Array>(capacity);
+		Array *new_array = allot_uninitialized_array<Array>(capacity);
 
 		memcpy(new_array + 1,array.untagged() + 1,to_copy * Array::element_size);
 		memset((char *)(new_array + 1) + to_copy * Array::element_size,
diff --git a/vm/io.cpp b/vm/io.cpp
index d5cfc1745c..a75f41c5bf 100755
--- a/vm/io.cpp
+++ b/vm/io.cpp
@@ -88,7 +88,7 @@ void factor_vm::primitive_fread()
 		return;
 	}
 
-	gc_root<byte_array> buf(allot_array_internal<byte_array>(size),this);
+	gc_root<byte_array> buf(allot_uninitialized_array<byte_array>(size),this);
 
 	for(;;)
 	{
diff --git a/vm/layouts.hpp b/vm/layouts.hpp
index 6e8c89ceb3..c25c2c0fc1 100644
--- a/vm/layouts.hpp
+++ b/vm/layouts.hpp
@@ -23,10 +23,7 @@ inline static cell align(cell a, cell b)
 	return (a + (b-1)) & ~(b-1);
 }
 
-inline static cell align8(cell a)
-{
-	return align(a,8);
-}
+static const cell data_alignment = 16;
 
 #define WORD_SIZE (signed)(sizeof(cell)*8)
 
@@ -186,6 +183,11 @@ struct byte_array : public object {
 	/* tagged */
 	cell capacity;
 
+#ifndef FACTOR_64
+	cell padding0;
+	cell padding1;
+#endif
+
 	template<typename Scalar> Scalar *data() { return (Scalar *)(this + 1); }
 };
 
@@ -249,9 +251,9 @@ struct code_block : public heap_block
 		return (void *)(this + 1);
 	}
 
-	cell type()
+	code_block_type type()
 	{
-		return (header >> 1) & 0x3;
+		return (code_block_type)((header >> 1) & 0x3);
 	}
 
 	void set_type(code_block_type type)
diff --git a/vm/strings.cpp b/vm/strings.cpp
index d7434fe660..23fa75acca 100644
--- a/vm/strings.cpp
+++ b/vm/strings.cpp
@@ -45,7 +45,7 @@ void factor_vm::set_string_nth_slow(string *str_, cell index, cell ch)
 		if the most significant bit of a
 		character is set. Initially all of
 		the bits are clear. */
-		aux = allot_array_internal<byte_array>(untag_fixnum(str->length) * sizeof(u16));
+		aux = allot_uninitialized_array<byte_array>(untag_fixnum(str->length) * sizeof(u16));
 
 		str->aux = tag<byte_array>(aux);
 		write_barrier(&str->aux);
diff --git a/vm/vm.hpp b/vm/vm.hpp
index a2f979e400..87697d5a0f 100755
--- a/vm/vm.hpp
+++ b/vm/vm.hpp
@@ -298,7 +298,7 @@ struct factor_vm
 	}
 
 	// generic arrays
-	template<typename Array> Array *allot_array_internal(cell capacity);
+	template<typename Array> Array *allot_uninitialized_array(cell capacity);
 	template<typename Array> bool reallot_array_in_place_p(Array *array, cell capacity);
 	template<typename Array> Array *reallot_array(Array *array_, cell capacity);
 
diff --git a/vm/zone.hpp b/vm/zone.hpp
index 4fe4ae9b6b..2c28922fbc 100644
--- a/vm/zone.hpp
+++ b/vm/zone.hpp
@@ -18,7 +18,7 @@ struct zone {
 	inline object *allot(cell size)
 	{
 		cell h = here;
-		here = h + align8(size);
+		here = h + align(size,data_alignment);
 		return (object *)h;
 	}
 };