diff --git a/lib/backend.py b/lib/backend.py
index 406a7f9aa38b4468048a868c4fc46fc98b24116f..8ea0fa7b6594bf94aca9db3f6a117790a3833295 100644
--- a/lib/backend.py
+++ b/lib/backend.py
@@ -646,10 +646,12 @@ def CreateBlockDevice(disk, size, owner, on_primary, info):
   """Creates a block device for an instance.
 
   Args:
-   bdev: a ganeti.objects.Disk object
-   size: the size of the physical underlying devices
-   do_open: if the device should be `Assemble()`-d and
-            `Open()`-ed after creation
+   disk: a ganeti.objects.Disk object
+   size: the size of the physical underlying device
+   owner: a string with the name of the instance
+   on_primary: a boolean indicating if it will be created on the primary
+     node or not
+   info: string 
 
   Returns:
     the new unique_id of the device (this can sometime be
@@ -1539,7 +1541,7 @@ class HooksRunner(object):
 
 
 class DevCacheManager(object):
-  """Simple class for managing a chache of block device information.
+  """Simple class for managing a cache of block device information.
 
   """
   _DEV_PREFIX = "/dev/"
diff --git a/lib/bdev.py b/lib/bdev.py
index f7adf70c97dbdb3ed221cb5ff08f31c01b101c1f..c7d2a83b1403ea97a170341d9c8b9543d598b02e 100644
--- a/lib/bdev.py
+++ b/lib/bdev.py
@@ -395,12 +395,11 @@ class LogicalVolume(BlockDev):
     self._lv_name = new_name
     self.dev_path = "/dev/%s/%s" % (self._vg_name, self._lv_name)
 
-
   def Attach(self):
     """Attach to an existing LV.
 
     This method will try to see if an existing and active LV exists
-    which matches the our name. If so, its major/minor will be
+    which matches our name. If so, its major/minor will be
     recorded.
 
     """
diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index 11c98bc87672c388e025c510ab64516057fc97f4..173cb16005fedc30dba1fdeebce55f493f6979a3 100644
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -3756,7 +3756,7 @@ class LUReplaceDisks(LogicalUnit):
       # ok, we created the new LVs, so now we know we have the needed
       # storage; as such, we proceed on the target node to rename
       # old_lv to _old, and new_lv to old_lv; note that we rename LVs
-      # using the assumption than logical_id == physical_id (which in
+      # using the assumption that logical_id == physical_id (which in
       # turn is the unique_id on that node)
 
       # FIXME(iustin): use a better name for the replaced LVs
diff --git a/lib/mcpu.py b/lib/mcpu.py
index 564d146bb16c616b66bb45bc73541fb3483028f7..cd1a3a9d8b7f77c9d793271bb50105eb4d0fd997 100644
--- a/lib/mcpu.py
+++ b/lib/mcpu.py
@@ -104,8 +104,7 @@ class Processor(object):
     """Execute an opcode.
 
     Args:
-     - cfg: the configuration in which we execute this opcode
-     - opcode: the opcode to be executed
+      op: the opcode to be executed
 
     """
     if not isinstance(op, opcodes.OpCode):