A backup is really a copy of a file to protect yourself against data loss should something happen, so it's always a much more immediate need. An archive is really a copy of certain records that could be completely taken out of context of their initial environment or structure and that are kept for future reference, not for recovery purposes.
@24684 For example, if you have a customer database, there are all kinds of records in there. Some of the records may date back to 1999. Chances are you don't really need those to do your everyday business, but this is something you keep for whatever reason. There's a possibility here to archive part of this, yet you still backup your database everyday in case something happens because you need to access these records immediately.
So, there's a very specific distinction between the two and archives should not be used or considered to be used for disaster recovery purposes -- really a backup is what counts for disaster recovery. You would restore from your backups, but you don't necessarily retrieve your archives following a disaster. This archive data is far away, kept somewhere safe in case you need it; not for recovery purposes.
Go to the beginning of the Disaster Recovery FAQ Guide