Is all it seems?

Is this true "de-dup" i.e. at file segment or block level or is it simply single instance?

What about impact on restore times if pulling back from tape? Performance metrics?

Is there anybody out there who isn't doing 2 stage backup these days

We're not that big of a shop, and our data protection scheme starts with a disk-to-disk backup for easy recover of the near-realtime data, with the disk storage then being run to tape. Since the de-duping is easily done on disk, what's the need for the tape to do it?