-* Switch over to a new hash algorithm beyond SHA-1, probably SHA-256.
-(The system is designed to allow this, but see how it works in
-practice.)
+* Rename cumulus to cumulus-backup, and write a new Python program,
+simply called cumulus, to replace the functions in cumulus-util and act
+as a wrapper for cumulus-backup. Integrate automatic segment cleaning
+and backup expiration.