diff --git a/nilmdb/fileinterval.py b/nilmdb/fileinterval.py
index af016a7..a3082a6 100644
--- a/nilmdb/fileinterval.py
+++ b/nilmdb/fileinterval.py
@@ -9,6 +9,24 @@ import bisect
 class FileInterval(Interval):
     """Represents an interval of time and its corresponding data"""
 
+    def __init__(self, start, end, 
+                 filename, 
+                 start_offset = None, end_offset = None):
+        self.start = start
+        self.end = end
+        self.filename = filename
+        if start_offset is None:
+            start_offset = 0
+        self.start_offset = start_offset
+        if end_offset is None:
+            f = open(filename, 'rb')
+            f.seek(0, os.SEEK_END)
+            end_offset = f.tell()
+        self.end_offset = end_offset
+
+    def __setattr__(self, name, value):
+        
+
     def subset(self, start, end):
         """Return a new Interval that is a subset of this one"""
         # TODO: Any magic regarding file/offset/length mapping for subsets
diff --git a/nilmdb/interval.py b/nilmdb/interval.py
index 3262b90..ccfb26c 100644
--- a/nilmdb/interval.py
+++ b/nilmdb/interval.py
@@ -12,6 +12,9 @@ class IntervalError(Exception):
 class Interval(object):
     """Represents an interval of time"""
 
+    start = None
+    end = None
+
     def __init__(self, start, end):
         self.start = start
         self.end = end
@@ -22,9 +25,6 @@ class Interval(object):
     def __str__(self):
         return "[" + str(self.start) + " -> " + str(self.end) + "]"
 
-    def __getattr__(self, name):
-        return { }
-
     def __setattr__(self, name, value):
         """Set attribute"""
         # TODO: If we need to manipulate file names, offsets, lengths, etc,
diff --git a/nilmdb/test_fileinterval.py b/nilmdb/test_fileinterval.py
index 3069f86..25ded45 100644
--- a/nilmdb/test_fileinterval.py
+++ b/nilmdb/test_fileinterval.py
@@ -12,10 +12,10 @@ def fiset(string):
         if (c == "["):
             start = day
         elif (c == "|"):
-            iset += FileInterval(start, day)
+            iset += FileInterval(start, day, "test.dat")
             start = day
         elif (c == "]"):
-            iset += FileInterval(start, day)
+            iset += FileInterval(start, day, "test.dat")
             del start
     return iset