diff --git a/djangoapps/courseware/capa/capa_problem.py b/djangoapps/courseware/capa/capa_problem.py
index c5a81e8100..9835b598b2 100644
--- a/djangoapps/courseware/capa/capa_problem.py
+++ b/djangoapps/courseware/capa/capa_problem.py
@@ -53,13 +53,12 @@ html_special_response = {"textline":textline.render,
                          "schematic":schematic.render}
 
 class LoncapaProblem(object):
-    def __init__(self, filename, id=None, state=None, seed=None):
+    def __init__(self, fileobject, id=None, state=None, seed=None):
         ## Initialize class variables from state
         self.seed = None
         self.student_answers = dict()
         self.correct_map = dict()
         self.done = False
-        self.filename = filename
 
         if seed != None:
             self.seed = seed
@@ -69,7 +68,6 @@ class LoncapaProblem(object):
         else:
             print "NO ID"
             raise Exception("This should never happen (183)")
-            #self.problem_id = filename
 
         if state:
             if 'seed' in state:
@@ -81,17 +79,12 @@ class LoncapaProblem(object):
             if 'done' in state:
                 self.done = state['done']
 
-#        print self.seed
-
         # TODO: Does this deplete the Linux entropy pool? Is this fast enough?
         if not self.seed:
             self.seed=struct.unpack('i', os.urandom(4))[0]
 
-#        print filename, self.seed, seed
-
         ## Parse XML file
-        #log.debug(u"LoncapaProblem() opening file {0}".format(filename))
-        file_text = open(filename).read()
+        file_text = fileobject.read()
         # Convert startouttext and endouttext to proper <text></text>
         # TODO: Do with XML operations
         file_text = re.sub("startouttext\s*/","text",file_text)
diff --git a/djangoapps/courseware/module_render.py b/djangoapps/courseware/module_render.py
index 2924aec9df..ac76eb08ae 100644
--- a/djangoapps/courseware/module_render.py
+++ b/djangoapps/courseware/module_render.py
@@ -18,8 +18,12 @@ from django.http import HttpResponse
 from django.shortcuts import redirect
 from django.template import Context
 from django.template import Context, loader
+
+from fs.osfs import OSFS
+
 from mitxmako.shortcuts import render_to_response, render_to_string
 
+
 from models import StudentModule
 from student.models import UserProfile
 import track.views
@@ -30,6 +34,14 @@ import courseware.modules
 
 log = logging.getLogger("mitx.courseware")
 
+class I4xSystem(object):
+    def __init__(self, ajax_url, track_function, render_function, filestore=None):
+        self.ajax_url = ajax_url
+        self.track_function = track_function
+        self.filestore = OSFS(settings.DATA_DIR)
+        self.render_function = render_function
+        self.exception404 = Http404
+
 def object_cache(cache, user, module_type, module_id):
     # We don't look up on user -- all queries include user
     # Additional lookup would require a DB hit the way Django 
@@ -76,12 +88,15 @@ def modx_dispatch(request, module=None, dispatch=None, id=None):
     xml = content_parser.module_xml(request.user, module, 'id', id)
 
     # Create the module
-    instance=courseware.modules.get_module_class(module)(xml, 
+    system = I4xSystem(track_function = make_track_function(request), 
+                       render_function = None, 
+                       ajax_url = ajax_url,
+                       filestore = None
+                       )
+    instance=courseware.modules.get_module_class(module)(system, 
+                                                         xml, 
                                                          id, 
-                                                         ajax_url=ajax_url, 
-                                                         state=oldstate, 
-                                                         track_function = make_track_function(request), 
-                                                         render_function = None)
+                                                         state=oldstate)
     # Let the module handle the AJAX
     ajax_return=instance.handle_ajax(dispatch, request.POST)
     # Save the state back to the database
@@ -128,12 +143,15 @@ def render_x_module(user, request, xml_module, module_object_preload):
 
     # Create a new instance
     ajax_url = '/modx/'+module_type+'/'+module_id+'/'
-    instance=module_class(etree.tostring(xml_module), 
+    system = I4xSystem(track_function = make_track_function(request), 
+                       render_function = lambda x: render_module(user, request, x, module_object_preload), 
+                       ajax_url = ajax_url,
+                       filestore = None
+                       )
+    instance=module_class(system, 
+                          etree.tostring(xml_module), 
                           module_id, 
-                          ajax_url=ajax_url,
-                          state=state, 
-                          track_function = make_track_function(request), 
-                          render_function = lambda x: render_module(user, request, x, module_object_preload))
+                          state=state)
     
     # If instance wasn't already in the database, create it
     if not smod:
diff --git a/djangoapps/courseware/modules/capa_module.py b/djangoapps/courseware/modules/capa_module.py
index 86958dcf1c..5c2f6be5c3 100644
--- a/djangoapps/courseware/modules/capa_module.py
+++ b/djangoapps/courseware/modules/capa_module.py
@@ -16,9 +16,7 @@ import traceback
 from lxml import etree
 
 ## TODO: Abstract out from Django
-from django.conf import settings
-from mitxmako.shortcuts import render_to_response, render_to_string
-from django.http import Http404
+from mitxmako.shortcuts import render_to_string
 
 from x_module import XModule
 from courseware.capa.capa_problem import LoncapaProblem, StudentInputError
@@ -92,7 +90,6 @@ class Module(XModule):
         # User submitted a problem, and hasn't reset. We don't want
         # more submissions. 
         if self.lcp.done and self.rerandomize == "always":
-            #print "!"
             check_button = False
             save_button = False
         
@@ -131,8 +128,8 @@ class Module(XModule):
             
         return html
 
-    def __init__(self, xml, item_id, ajax_url=None, track_url=None, state=None, track_function=None, render_function = None, meta = None):
-        XModule.__init__(self, xml, item_id, ajax_url, track_url, state, track_function, render_function)
+    def __init__(self, system, xml, item_id, state=None):
+        XModule.__init__(self, system, xml, item_id, state)
 
         self.attempts = 0
         self.max_attempts = None
@@ -185,15 +182,14 @@ class Module(XModule):
         if state!=None and 'attempts' in state:
             self.attempts=state['attempts']
 
-        self.filename=content_parser.item(dom2.xpath('/problem/@filename'))
-        filename=settings.DATA_DIR+"/problems/"+self.filename+".xml"
+        self.filename="problems/"+content_parser.item(dom2.xpath('/problem/@filename'))+".xml"
         self.name=content_parser.item(dom2.xpath('/problem/@name'))
         self.weight=content_parser.item(dom2.xpath('/problem/@weight'))
         if self.rerandomize == 'never':
             seed = 1
         else:
             seed = None
-        self.lcp=LoncapaProblem(filename, self.item_id, state, seed = seed)
+        self.lcp=LoncapaProblem(self.filestore.open(self.filename), self.item_id, state, seed = seed)
 
     def handle_ajax(self, dispatch, get):
         if dispatch=='problem_get':
@@ -242,16 +238,15 @@ class Module(XModule):
         if self.show_answer == 'closed' and not self.closed():
             return False
         print "aa", self.show_answer
-        raise Http404
+        raise self.system.exception404 #TODO: Not 404
 
     def get_answer(self, get):
         if not self.answer_available():
-            raise Http404
+            raise self.system.exception404
         else: 
             return json.dumps(self.lcp.get_question_answers(), 
                               cls=ComplexEncoder)
 
-
     # Figure out if we should move these to capa_problem?
     def get_problem(self, get):
         ''' Same as get_problem_html -- if we want to reconfirm we
@@ -270,41 +265,33 @@ class Module(XModule):
         for key in get:
             answers['_'.join(key.split('_')[1:])]=get[key]
 
-#        print "XXX", answers, get
-
         event_info['answers']=answers
 
         # Too late. Cannot submit
         if self.closed():
             event_info['failure']='closed'
             self.tracker('save_problem_check_fail', event_info)
-            print "cp"
-            raise Http404
+            raise self.system.exception404
             
         # Problem submitted. Student should reset before checking
         # again.
         if self.lcp.done and self.rerandomize == "always":
             event_info['failure']='unreset'
             self.tracker('save_problem_check_fail', event_info)
-            print "cpdr"
-            raise Http404
+            raise self.system.exception404
 
         try:
             old_state = self.lcp.get_state()
             lcp_id = self.lcp.problem_id
-            filename = self.lcp.filename
             correct_map = self.lcp.grade_answers(answers)
         except StudentInputError as inst: 
-            self.lcp = LoncapaProblem(filename, id=lcp_id, state=old_state)
+            self.lcp = LoncapaProblem(self.filestore.open(self.filename), id=lcp_id, state=old_state)
             traceback.print_exc()
-#            print {'error':sys.exc_info(),
-#                   'answers':answers, 
-#                   'seed':self.lcp.seed, 
-#                   'filename':self.lcp.filename}
             return json.dumps({'success':inst.message})
         except: 
-            self.lcp = LoncapaProblem(filename, id=lcp_id, state=old_state)
+            self.lcp = LoncapaProblem(self.filestore.open(self.filename), id=lcp_id, state=old_state)
             traceback.print_exc()
+            raise
             return json.dumps({'success':'Unknown Error'})
             
 
@@ -382,8 +369,8 @@ class Module(XModule):
             self.lcp.questions=dict() # Detailed info about questions in problem instance. TODO: Should be by id and not lid. 
             self.lcp.seed=None
 
-        filename=settings.DATA_DIR+"problems/"+self.filename+".xml"
-        self.lcp=LoncapaProblem(filename, self.item_id, self.lcp.get_state())
+        filename="problems/"+self.filename+".xml"
+        self.lcp=LoncapaProblem(self.filestore.open(filename), self.item_id, self.lcp.get_state())
 
         event_info['new_state']=self.lcp.get_state()
         self.tracker('reset_problem', event_info)
diff --git a/djangoapps/courseware/modules/html_module.py b/djangoapps/courseware/modules/html_module.py
index 4194f73e74..77bcbb4bbc 100644
--- a/djangoapps/courseware/modules/html_module.py
+++ b/djangoapps/courseware/modules/html_module.py
@@ -1,7 +1,5 @@
 import json
 
-## TODO: Abstract out from Django
-from django.conf import settings
 from mitxmako.shortcuts import render_to_response, render_to_string
 
 from x_module import XModule
@@ -24,13 +22,13 @@ class Module(XModule):
             textlist=[i for i in textlist if type(i)==str]
             return "".join(textlist)
         try: 
-            filename=settings.DATA_DIR+"html/"+self.filename
-            return open(filename).read()
+            filename="html/"+self.filename
+            return self.filestore.open(filename).read()
         except: # For backwards compatibility. TODO: Remove
             return render_to_string(self.filename, {'id': self.item_id})
 
-    def __init__(self, xml, item_id, ajax_url=None, track_url=None, state=None, track_function=None, render_function = None):
-        XModule.__init__(self, xml, item_id, ajax_url, track_url, state, track_function, render_function)
+    def __init__(self, system, xml, item_id, state=None):
+        XModule.__init__(self, system, xml, item_id, state)
         xmltree=etree.fromstring(xml)
         self.filename = None
         filename_l=xmltree.xpath("/html/@filename")
diff --git a/djangoapps/courseware/modules/schematic_module.py b/djangoapps/courseware/modules/schematic_module.py
index e253f1acc6..5fef265e01 100644
--- a/djangoapps/courseware/modules/schematic_module.py
+++ b/djangoapps/courseware/modules/schematic_module.py
@@ -19,6 +19,6 @@ class Module(XModule):
     def get_html(self):
         return '<input type="hidden" class="schematic" name="{item_id}" height="480" width="640">'.format(item_id=self.item_id)
 
-    def __init__(self, xml, item_id, ajax_url=None, track_url=None, state=None, render_function = None):
-        XModule.__init__(self, xml, item_id, ajax_url, track_url, state, render_function)
+    def __init__(self, system, xml, item_id, state=None):
+        XModule.__init__(self, system, xml, item_id, state)
 
diff --git a/djangoapps/courseware/modules/seq_module.py b/djangoapps/courseware/modules/seq_module.py
index 80e0b4c7bf..161c95b604 100644
--- a/djangoapps/courseware/modules/seq_module.py
+++ b/djangoapps/courseware/modules/seq_module.py
@@ -2,9 +2,7 @@ import json
 
 from lxml import etree
 
-## TODO: Abstract out from Django
-from django.http import Http404
-from mitxmako.shortcuts import render_to_string
+from mitxmako.shortcuts import render_to_response, render_to_string
 
 from x_module import XModule
 
@@ -37,12 +35,10 @@ class Module(XModule):
         return self.destroy_js
 
     def handle_ajax(self, dispatch, get):
-        print "GET", get
-        print "DISPATCH", dispatch
         if dispatch=='goto_position':
             self.position = int(get['position'])
             return json.dumps({'success':True})
-        raise Http404()
+        raise self.system.exception404
 
     def render(self):
         if self.rendered:
@@ -106,9 +102,8 @@ class Module(XModule):
         self.rendered = True
         
 
-
-    def __init__(self, xml, item_id, ajax_url=None, track_url=None, state=None, track_function=None, render_function = None):
-        XModule.__init__(self, xml, item_id, ajax_url, track_url, state, track_function, render_function)
+    def __init__(self, system, xml, item_id, state=None):
+        XModule.__init__(self, system, xml, item_id, state)
         self.xmltree=etree.fromstring(xml)
 
         self.position = 1
diff --git a/djangoapps/courseware/modules/template_module.py b/djangoapps/courseware/modules/template_module.py
index d9dbb613f0..41556eb9d4 100644
--- a/djangoapps/courseware/modules/template_module.py
+++ b/djangoapps/courseware/modules/template_module.py
@@ -14,16 +14,16 @@ class Module(XModule):
 
     @classmethod
     def get_xml_tags(c):
+        ## TODO: Abstract out from filesystem
         tags = os.listdir(settings.DATA_DIR+'/custom_tags')
         return tags
 
     def get_html(self):
         return self.html
 
-    def __init__(self, xml, item_id, ajax_url=None, track_url=None, state=None, track_function=None, render_function = None):
-        XModule.__init__(self, xml, item_id, ajax_url, track_url, state, track_function, render_function)
+    def __init__(self, system, xml, item_id, state=None):
+        XModule.__init__(self, system, xml, item_id, state)
         xmltree = etree.fromstring(xml)
         filename = xmltree.tag
         params = dict(xmltree.items())
-#        print params
         self.html = render_to_string(filename, params, namespace = 'custom_tags')
diff --git a/djangoapps/courseware/modules/vertical_module.py b/djangoapps/courseware/modules/vertical_module.py
index c068cb9a76..f64e45fe7f 100644
--- a/djangoapps/courseware/modules/vertical_module.py
+++ b/djangoapps/courseware/modules/vertical_module.py
@@ -1,7 +1,5 @@
 import json
 
-## TODO: Abstract out from Django
-from django.conf import settings
 from mitxmako.shortcuts import render_to_response, render_to_string
 
 from x_module import XModule
@@ -26,8 +24,9 @@ class Module(XModule):
     def get_destroy_js(self):
         return self.destroy_js_text
 
-    def __init__(self, xml, item_id, ajax_url=None, track_url=None, state=None, track_function=None, render_function = None):
-        XModule.__init__(self, xml, item_id, ajax_url, track_url, state, track_function, render_function)
+
+    def __init__(self, system, xml, item_id, state=None):
+        XModule.__init__(self, system, xml, item_id, state)
         xmltree=etree.fromstring(xml)
         self.contents=[(e.get("name"),self.render_function(e)) \
                       for e in xmltree]
diff --git a/djangoapps/courseware/modules/video_module.py b/djangoapps/courseware/modules/video_module.py
index f116853447..c678838f2b 100644
--- a/djangoapps/courseware/modules/video_module.py
+++ b/djangoapps/courseware/modules/video_module.py
@@ -3,9 +3,7 @@ import logging
 
 from lxml import etree
 
-## TODO: Abstract out from Django
-from django.http import Http404
-from mitxmako.shortcuts import render_to_string
+from mitxmako.shortcuts import render_to_response, render_to_string
 
 from x_module import XModule
 
@@ -58,8 +56,8 @@ class Module(XModule):
     def get_destroy_js(self):
         return "videoDestroy(\"{0}\");".format(self.item_id)+self.annotations_destroy
 
-    def __init__(self, xml, item_id, ajax_url=None, track_url=None, state=None, track_function=None, render_function = None):
-        XModule.__init__(self, xml, item_id, ajax_url, track_url, state, track_function, render_function)
+    def __init__(self, system, xml, item_id, state=None):
+        XModule.__init__(self, system, xml, item_id, state)
         xmltree=etree.fromstring(xml)
         self.youtube = xmltree.get('youtube')
         self.name = xmltree.get('name')
diff --git a/djangoapps/courseware/modules/x_module.py b/djangoapps/courseware/modules/x_module.py
index 4a379253c4..b21894b36b 100644
--- a/djangoapps/courseware/modules/x_module.py
+++ b/djangoapps/courseware/modules/x_module.py
@@ -45,13 +45,14 @@ class XModule(object):
             get is a dictionary-like object ''' 
         return ""
 
-    def __init__(self, xml, item_id, ajax_url=None, track_url=None, state=None, track_function=None, render_function = None):
+    def __init__(self, system, xml, item_id, track_url=None, state=None):
         ''' In most cases, you must pass state or xml'''
         self.xml = xml
         self.item_id = item_id
-        self.ajax_url = ajax_url
-        self.track_url = track_url
         self.state = state
-        self.tracker = track_function
-        self.render_function = render_function
 
+        self.ajax_url = system.ajax_url
+        self.tracker = system.track_function
+        self.filestore = system.filestore
+        self.render_function = system.render_function
+        self.system = system