Uhh... no. Every single program I use that handles sensitive data saves in at least one-minute intervals.
I think he meant data loss from a hard drive getting fried.
I'm unaware of any RAID configuration that has the main intention of increasing capacity. RAID is used for write speed, drive integrity or a combination of the two.
In fact, with RAID 5 (At least 4 drives required), you entirely lose the functionality of one of the drives in the array for bit parity. The advantage is: if you lose one drive in the array, you lose none of your data. When it is replaced, the array rebuilds itself. On top of that, RAID 5 features data striping, so writing data is a lot faster. There are tons of RAID configurations, but 5 is probably the most practical/reliable for a workstation situation.
RAID is all fine and good (although a bitch to setup on XP), but if you don't need the write performance or 100% uptime on the data it serves, I think a simple backup is much better bang for the buck (ie on most workstations). My 80gb external hard drive (cost me ~$100 2 years ago) holds backups for all my computers. Ghost even schedules the backups such that I have a fresh backup every week with incrementals every day.
@Joe, there are actually two types of RAID. Hardware controlled and Software controlled. If you want to find out more, there are plenty of articles on the differences.
