I don't think that "all" storage systems will be unified [a.k.a. multiprotocol]. I do think you'll see a unified offering from all the major vendors because it's a very competitive world, and to not have an offering might be perceived a weakness or limitation on the vendor's part. But there are reasons to avoid unified storage; especially in cases where granular control needs and high performance requirements necessitate block-based storage. You'll continue to see independent block and file offerings. You will probably see file-based products that can be utilized as "NAS-only," or support an optional block-mode interface for unified storage; that will probably be the trend into the near future.
Listen to the unified storage FAQ audiocast.
Go to the beginning of the Unified Storage FAQ Guide.
This was first published in February 2007