In Research Computing we often use the terms “Rstor” and “AFS” together but they are not the same thing.
AFS (Andrew File System) is a distributed file system that has been in use at Dartmouth since the early 1990’s.
Rstor uses AFS as it’s underlying storage technology but is just a named service that was created in 2010 to provide defined amounts of storage and a purchase model for storage.
So AFS is the underlying technology and is the service name.