diff --git a/rpl/file_store.go b/rpl/file_store.go
index d6b9d26..127dd19 100644
--- a/rpl/file_store.go
+++ b/rpl/file_store.go
@@ -30,7 +30,15 @@ const (
 	data: log1 data | log2 data | magic data
 	meta: log1 pos in data | log2 pos in data
 
+	log id can not be 0, we use here for magic log
+	if data has no magic data, it means that we don't close replication gracefully.
+	so we must repair the log data
+	magic data = log0 data
+
 	we use table to mangage data + meta pair
+
+	we must guarantee that the log id is monotonic increment strictly.
+	if log1's id is 1, log2 must be 2
 */
 
 type FileStore struct {
diff --git a/rpl/file_table.go b/rpl/file_table.go
index def4355..2a81ebf 100644
--- a/rpl/file_table.go
+++ b/rpl/file_table.go
@@ -1 +1,29 @@
 package rpl
+
+import (
+	"fmt"
+	"os"
+	"path"
+)
+
+type table struct {
+	baseName string
+
+	index int64
+
+	readonly bool
+	df       *os.File
+	mf       *os.File
+
+	first uint64
+	last  uint64
+}
+
+func newReadTable(base string, index int64) (*table, error) {
+	t := new(table)
+
+	t.baseName = path.Join(base, fmt.Sprintf("%08d", index))
+	t.index = index
+
+	return t, nil
+}