A few years back, it became very hip to talk about continuous data protection (CDP).  CDP is a backup job that always runs. It is always monitoring disk writes and anytime there is a file saved, that file is immediately backed up.  In a lot of ways, it is great.  As soon as a change is saved or a file is committed, boom, the file is backed up.  However, it tends to be very resource intensive.  It tends to be expensive.  For very important data, this can still be quite useful, and worth the overhead.  Cash registers, a doctor’s laptop, the computer of a struggling screenwriter who left his wife and kid back in Kansas so he could go to Hollywood and get a movie made and move back home as a hero but who has been distracted by the cheap drugs and constant parties and for a moment forgot his own name after trying smack at a club on Sunset and was thrown out by the bouncer after vomiting on the stage, but the adreneline of being ejected and scraping his elbows on the cement cleared his head and shone a light on an idea that has been sitting right in front of him the whole time so he rushed home and has been typing a fully formed story for 19 hours straight – these are all good candidates for CDP.  Mirroring a database is also another example of CDP.  But for most applications and for most people, a scheduled regular and periodic backup is sufficient.