I always find this topic confusing in terms of what to actually teach the kids at AS Level. We use AQA and I am interested to know what you teach. Question: Describe Online Backup Depending on where you are in the spec " online" apparently means different things. In one section it is referred to as meaning "real time". In other words the output is fast enough to directly affect the next input such as playing a computer game. For a database, it is considered to be "online" if users are able to perform transactions (I assume that this means 2 phase commit etc is in operation) For a network "online" can mean simply connected to a LAN network - or a WAN (e.g. t'Internet). There are probably others but on we go to the topic in question. Online backup. AQA seem to regard this as either: a) RAID (I assume just level 0?) or b) Remote backup using online services such as cloud or a vendor usually over the internet (but it could be any WAN I suppose. Which one do you teach/advise? What do other exam boards say? Which one gets the marks?