diff --git a/AbstractTypes.hs b/AbstractTypes.hs
index 510a37f0cc..935d1de2f5 100644
--- a/AbstractTypes.hs
+++ b/AbstractTypes.hs
@@ -14,4 +14,34 @@ module AbstractTypes (
 	Backend
 ) where
 
-import Types
+import Control.Monad.State
+import qualified GitRepo as Git
+import BackendTypes
+
+-- constructor
+makeAnnexState :: Git.Repo -> AnnexState
+makeAnnexState g = AnnexState { repo = g, backends = [] }
+
+-- performs an action in the Annex monad
+runAnnexState state action = runStateT (action) state
+
+-- Annex monad state accessors
+gitAnnex :: Annex Git.Repo
+gitAnnex = do
+	state <- get
+	return (repo state)
+gitAnnexChange :: Git.Repo -> Annex ()
+gitAnnexChange r = do
+	state <- get
+	put state { repo = r }
+	return ()
+backendsAnnex :: Annex [Backend]
+backendsAnnex = do
+	state <- get
+	return (backends state)
+backendsAnnexChange :: [Backend] -> Annex ()
+backendsAnnexChange b = do
+	state <- get
+	put state { backends = b }
+	return ()
+
diff --git a/Backend.hs b/Backend.hs
index 1bd4efc1e8..251e436c75 100644
--- a/Backend.hs
+++ b/Backend.hs
@@ -30,7 +30,8 @@ import BackendList
 import Locations
 import qualified GitRepo as Git
 import Utility
-import Types
+import AbstractTypes
+import BackendTypes
 
 {- Attempts to store a file in one of the backends. -}
 storeFile :: FilePath -> Annex (Maybe (Key, Backend))
diff --git a/BackendChecksum.hs b/BackendChecksum.hs
index c6e68ffed4..50ef2ae6f6 100644
--- a/BackendChecksum.hs
+++ b/BackendChecksum.hs
@@ -5,7 +5,7 @@ module BackendChecksum (backend) where
 
 import qualified BackendFile
 import Data.Digest.Pure.SHA
-import Types
+import BackendTypes
 
 -- based on BackendFile just with a different key type
 backend = BackendFile.backend {
diff --git a/BackendFile.hs b/BackendFile.hs
index a0396f51da..284daca88e 100644
--- a/BackendFile.hs
+++ b/BackendFile.hs
@@ -7,7 +7,7 @@ import Control.Monad.State
 import System.IO
 import System.Cmd
 import Control.Exception
-import Types
+import BackendTypes
 import LocationLog
 import Locations
 import qualified Remotes
diff --git a/BackendList.hs b/BackendList.hs
index 104444dc20..91a2fa7fc3 100644
--- a/BackendList.hs
+++ b/BackendList.hs
@@ -7,7 +7,7 @@ module BackendList (
 	lookupBackendName
 ) where
 
-import Types
+import BackendTypes
 
 -- When adding a new backend, import it here and add it to the list.
 import qualified BackendFile
diff --git a/Types.hs b/BackendTypes.hs
similarity index 55%
rename from Types.hs
rename to BackendTypes.hs
index c9d33affdd..2ef65f4691 100644
--- a/Types.hs
+++ b/BackendTypes.hs
@@ -1,12 +1,16 @@
-{- git-annex core data types -}
+{- git-annex backend data types
+ -
+ - Mostly only backend implementations should need to import this.
+ -}
 
-module Types where
+module BackendTypes where
 
 import Control.Monad.State
 import Data.String.Utils
 import qualified GitRepo as Git
 
--- git-annex's runtime state
+-- git-annex's runtime state type doesn't really belong here,
+-- but it uses Backend, so has to be here to avoid a depends loop.
 data AnnexState = AnnexState {
 	repo :: Git.Repo,
 	backends :: [Backend]
@@ -15,33 +19,6 @@ data AnnexState = AnnexState {
 -- git-annex's monad
 type Annex = StateT AnnexState IO
 
--- constructor
-makeAnnexState :: Git.Repo -> AnnexState
-makeAnnexState g = AnnexState { repo = g, backends = [] }
-
--- performs an action in the Annex monad
-runAnnexState state action = runStateT (action) state
-
--- Annex monad state accessors
-gitAnnex :: Annex Git.Repo
-gitAnnex = do
-	state <- get
-	return (repo state)
-gitAnnexChange :: Git.Repo -> Annex ()
-gitAnnexChange r = do
-	state <- get
-	put state { repo = r }
-	return ()
-backendsAnnex :: Annex [Backend]
-backendsAnnex = do
-	state <- get
-	return (backends state)
-backendsAnnexChange :: [Backend] -> Annex ()
-backendsAnnexChange b = do
-	state <- get
-	put state { backends = b }
-	return ()
-
 -- annexed filenames are mapped into keys
 data Key = Key String deriving (Eq)
 
diff --git a/BackendUrl.hs b/BackendUrl.hs
index 43b0bc75a8..fc0a8ae586 100644
--- a/BackendUrl.hs
+++ b/BackendUrl.hs
@@ -6,7 +6,7 @@ module BackendUrl (backend) where
 import Control.Monad.State
 import System.Cmd
 import IO
-import Types
+import BackendTypes
 
 backend = Backend {
 	name = "url",
diff --git a/Locations.hs b/Locations.hs
index 5d701681c1..8c1915b021 100644
--- a/Locations.hs
+++ b/Locations.hs
@@ -11,7 +11,8 @@ module Locations (
 ) where
 
 import Data.String.Utils
-import Types
+import AbstractTypes
+import qualified BackendTypes as Backend
 import qualified GitRepo as Git
 
 {- Long-term, cross-repo state is stored in files inside the .git-annex
@@ -32,7 +33,7 @@ annexLocation r backend key =
 {- Annexed file's location relative to the gitWorkTree -}
 annexLocationRelative :: Git.Repo -> Backend -> Key -> FilePath
 annexLocationRelative r backend key = 
-	Git.dir r ++ "/annex/" ++ (name backend) ++ "/" ++ (keyFile key)
+	Git.dir r ++ "/annex/" ++ (Backend.name backend) ++ "/" ++ (keyFile key)
 
 {- Converts a key into a filename fragment.
  -
@@ -50,4 +51,5 @@ keyFile key = replace "/" "%" $ replace "%" "&s" $ replace "&" "&a" $ show key
 {- Reverses keyFile, converting a filename fragment (ie, the basename of
  - the symlink target) into a key. -}
 fileKey :: FilePath -> Key
-fileKey file = Key $ replace "&a" "&" $ replace "&s" "%" $ replace "%" "/" file
+fileKey file = Backend.Key $ 
+	replace "&a" "&" $ replace "&s" "%" $ replace "%" "/" file