diff --git a/Makefile.in b/Makefile.in
index d08f8cf..e54fbd5 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -36,6 +36,7 @@ all: $(PROGRAMS)
 
 SOURCE=\
 	base/base64.cc \
+	base/endian_utils.cc \
 	base/error_state.cc \
 	\
 	caching/hint_array.cc \
@@ -46,8 +47,9 @@ SOURCE=\
 	caching/restore_emitter.cc \
 	caching/xml_format.cc \
 	\
+	era/era_detail.cc \
+	\
 	persistent-data/checksum.cc \
-	persistent-data/endian_utils.cc \
 	persistent-data/error_set.cc \
 	persistent-data/file_utils.cc \
 	persistent-data/hex_dump.cc \
@@ -154,8 +156,9 @@ THIN_REPAIR_SOURCE=$(SOURCE)
 THIN_RESTORE_SOURCE=$(SOURCE)
 THIN_CHECK_SOURCE=\
 	base/error_state.cc \
+	base/endian_utils.cc \
+	\
 	persistent-data/checksum.cc \
-	persistent-data/endian_utils.cc \
 	persistent-data/error_set.cc \
 	persistent-data/file_utils.cc \
 	persistent-data/hex_dump.cc \
@@ -166,6 +169,7 @@ THIN_CHECK_SOURCE=\
 	persistent-data/space-maps/recursive.cc \
 	persistent-data/space-maps/careful_alloc.cc \
 	persistent-data/transaction_manager.cc \
+	\
 	thin-provisioning/device_tree.cc \
 	thin-provisioning/mapping_tree.cc \
 	thin-provisioning/metadata.cc \
@@ -173,8 +177,9 @@ THIN_CHECK_SOURCE=\
 	thin-provisioning/superblock.cc
 
 THIN_RMAP_SOURCE=\
+	base/endian_utils.cc \
+	\
 	persistent-data/checksum.cc \
-	persistent-data/endian_utils.cc \
 	persistent-data/error_set.cc \
 	persistent-data/file_utils.cc \
 	persistent-data/hex_dump.cc \
@@ -233,8 +238,9 @@ thin_metadata_size: thin-provisioning/thin_metadata_size.o
 CACHE_CHECK_SOURCE=\
 	base/base64.cc \
 	base/error_state.cc \
+	base/endian_utils.cc \
+	\
 	persistent-data/checksum.cc \
-	persistent-data/endian_utils.cc \
 	persistent-data/error_set.cc \
 	persistent-data/file_utils.cc \
 	persistent-data/hex_dump.cc \
@@ -246,6 +252,7 @@ CACHE_CHECK_SOURCE=\
 	persistent-data/space-maps/recursive.cc \
 	persistent-data/space-maps/careful_alloc.cc \
 	persistent-data/transaction_manager.cc \
+	\
 	caching/hint_array.cc \
 	caching/superblock.cc \
 	caching/mapping_array.cc \
diff --git a/persistent-data/endian_utils.cc b/base/endian_utils.cc
similarity index 100%
rename from persistent-data/endian_utils.cc
rename to base/endian_utils.cc
diff --git a/persistent-data/endian_utils.h b/base/endian_utils.h
similarity index 97%
rename from persistent-data/endian_utils.h
rename to base/endian_utils.h
index 39276e6..3ad75ae 100644
--- a/persistent-data/endian_utils.h
+++ b/base/endian_utils.h
@@ -16,8 +16,8 @@
 // with thin-provisioning-tools.  If not, see
 // <http://www.gnu.org/licenses/>.
 
-#ifndef ENDIAN_H
-#define ENDIAN_H
+#ifndef BASE_ENDIAN_H
+#define BASE_ENDIAN_H
 
 #include <endian.h>
 #include <stdint.h>
@@ -25,7 +25,6 @@
 
 //----------------------------------------------------------------
 
-// FIXME: rename to endian
 namespace base {
 
 	// These are just little wrapper types to make the compiler
diff --git a/caching/mapping_array.cc b/caching/mapping_array.cc
index d31c2c9..c6af4ef 100644
--- a/caching/mapping_array.cc
+++ b/caching/mapping_array.cc
@@ -1,5 +1,5 @@
+#include "base/endian_utils.h"
 #include "caching/mapping_array.h"
-#include "persistent-data/endian_utils.h"
 
 #include <set>
 
diff --git a/caching/metadata.h b/caching/metadata.h
index 611b424..a606878 100644
--- a/caching/metadata.h
+++ b/caching/metadata.h
@@ -1,10 +1,11 @@
 #ifndef CACHE_METADATA_H
 #define CACHE_METADATA_H
 
+#include "base/endian_utils.h"
+
 #include "persistent-data/block.h"
 #include "persistent-data/data-structures/array.h"
 #include "persistent-data/data-structures/bitset.h"
-#include "persistent-data/endian_utils.h"
 #include "persistent-data/space-maps/disk.h"
 #include "persistent-data/transaction_manager.h"
 
diff --git a/caching/superblock.h b/caching/superblock.h
index 2c2cf30..d1a24aa 100644
--- a/caching/superblock.h
+++ b/caching/superblock.h
@@ -1,7 +1,7 @@
 #ifndef CACHE_SUPERBLOCK_H
 #define CACHE_SUPERBLOCK_H
 
-#include "persistent-data/endian_utils.h"
+#include "base/endian_utils.h"
 #include "persistent-data/data-structures/btree.h"
 
 #include <set>
diff --git a/persistent-data/data-structures/array_block.h b/persistent-data/data-structures/array_block.h
index 1bb3d4c..638e164 100644
--- a/persistent-data/data-structures/array_block.h
+++ b/persistent-data/data-structures/array_block.h
@@ -19,7 +19,7 @@
 #ifndef ARRAY_BLOCK_H
 #define ARRAY_BLOCK_H
 
-#include "persistent-data/endian_utils.h"
+#include "base/endian_utils.h"
 
 //----------------------------------------------------------------
 
diff --git a/persistent-data/data-structures/btree.h b/persistent-data/data-structures/btree.h
index 26e687a..93c3284 100644
--- a/persistent-data/data-structures/btree.h
+++ b/persistent-data/data-structures/btree.h
@@ -19,7 +19,7 @@
 #ifndef BTREE_H
 #define BTREE_H
 
-#include "persistent-data/endian_utils.h"
+#include "base/endian_utils.h"
 #include "persistent-data/transaction_manager.h"
 #include "persistent-data/data-structures/ref_counter.h"
 
diff --git a/persistent-data/space-maps/disk.cc b/persistent-data/space-maps/disk.cc
index 36937ec..1de3688 100644
--- a/persistent-data/space-maps/disk.cc
+++ b/persistent-data/space-maps/disk.cc
@@ -16,6 +16,8 @@
 // with thin-provisioning-tools.  If not, see
 // <http://www.gnu.org/licenses/>.
 
+#include "base/endian_utils.h"
+
 #include "persistent-data/space-maps/disk.h"
 #include "persistent-data/space-maps/disk_structures.h"
 #include "persistent-data/space-maps/recursive.h"
@@ -23,7 +25,6 @@
 
 #include "persistent-data/data-structures/btree_checker.h"
 #include "persistent-data/checksum.h"
-#include "persistent-data/endian_utils.h"
 #include "persistent-data/math_utils.h"
 #include "persistent-data/transaction_manager.h"
 
diff --git a/persistent-data/space-maps/disk_structures.h b/persistent-data/space-maps/disk_structures.h
index a92f490..1429d36 100644
--- a/persistent-data/space-maps/disk_structures.h
+++ b/persistent-data/space-maps/disk_structures.h
@@ -19,7 +19,7 @@
 #ifndef SPACE_MAP_DISK_STRUCTURES_H
 #define SPACE_MAP_DISK_STRUCTURES_H
 
-#include "persistent-data/endian_utils.h"
+#include "base/endian_utils.h"
 
 // FIXME: what's this included for?
 #include "persistent-data/data-structures/btree.h"
diff --git a/thin-provisioning/metadata.h b/thin-provisioning/metadata.h
index 9749acb..c0913a0 100644
--- a/thin-provisioning/metadata.h
+++ b/thin-provisioning/metadata.h
@@ -19,9 +19,10 @@
 #ifndef METADATA_LL_H
 #define METADATA_LL_H
 
+#include "base/endian_utils.h"
+
 #include "persistent-data/block.h"
 #include "persistent-data/data-structures/btree.h"
-#include "persistent-data/endian_utils.h"
 #include "persistent-data/space-maps/disk.h"
 #include "persistent-data/transaction_manager.h"
 
diff --git a/thin-provisioning/superblock.h b/thin-provisioning/superblock.h
index d6d78e3..3a3d90a 100644
--- a/thin-provisioning/superblock.h
+++ b/thin-provisioning/superblock.h
@@ -1,8 +1,9 @@
 #ifndef THIN_SUPERBLOCK_H
 #define THIN_SUPERBLOCK_H
 
+#include "base/endian_utils.h"
+
 #include "persistent-data/block.h"
-#include "persistent-data/endian_utils.h"
 #include "persistent-data/data-structures/ref_counter.h"
 
 //----------------------------------------------------------------