[atYevP]

No one (outside Amazon) truly knows what Glacier is on, likely it is a combination, and tape may play a role, that's why it's relatively inexpensive to house the data, but the costs to get it back are very high and are for "emergency, everything else has failed" situations.

[dmourati]

Asked what IT equipment Glacier uses, Amazon told ZDNet it does not run on tape. "Essentially you can see this as a replacement for tape," a company spokesman said via email.

http://www.zdnet.com/amazon-launches-glacier-cloud-storage-h...

See also: http://en.wikipedia.org/wiki/Amazon_Glacier#Storage