RAID names a concept of using several hard disks as if they were single. It's the abbreviation for Redundant Array of Independent Disks (I guess and wont verify this now). There are 7 or 8 different RAID configuration options, but the most common for desktop PCs are NRAID (JBOD), 0 and 1. This might be because most modern mainboards only support these three. Perhaps they only those 3 modes because that's most common for desktops... however.

Recently my workstation died a quiet death and I suddenly was without a computer at home. Well, glad as I am, it was not that suddenly at all, because I knew there was something wrong with either the mainboard or the power supply. I had some backups on an external storage and therefore there was not too much data loss to fear. Weeks ago I bought a new PC for about 500 Euros willing to work hard for me.