RAID-7 - What is the data organization?

The application my company develops keeps historical data around for a year and can need up to 2-2.5 GB a week. This is an extreme case, but possible. One of our customers has asked me for a recommendation regarding a reasonable storage method. In my reading RAID-7 appears occasionally. I am trying to figure out what it is, most of the internet info is very sales oriented. I want a little more depth. I am trying to figure out what the storare organization looks like. The one thing I found was at www.storage.com saying that, "Data is block striped across the array and parity data is held on one or more dedicated drives." This sounds like RAID-4 to me, with the exception RL4 uses one parity drive, this stuff sounds like it has multiple. Anyone know anything definitive? Thanks, Charlie