Microsoft announced the BI Semantic Model @ the PASS Summit.
Chris Webb was there and he gave his opinion on his Blog
The quotes below are from Chris Webb’s blogpost here. Thanks for that Chris!
The BISM – BI Semantic Model – is the name for the new type of Analysis Services database that gets created when you publish a PowerPivot model up to the server. It’s SSAS running in the special in-memory mode, and SSAS instances will either work in this mode or in regular MOLAP mode. In Denali we’ll be able to install a standalone instance of SSAS running in in-memory, BISM mode without needing Sharepoint around.
MS are clear that BISM is the priority now. While MOLAP SSAS isn’t deprecated, the efforts of the SSAS dev team are concentrated on BISM and PowerPivot and we shouldn’t expect any radical new changes. I asked why they couldn’t have just kept SSAS as it is today and bolted Vertipaq storage on as a new storage mode (we will, of course, be able to use SSAS cubes in ROLAP mode against SQL Server/PDW with Vertipaq relational indexes) but I was told that it was seriously considered, but didn’t turn out to be easy to implement at all. The other question I asked was why they are abandoning the concept of cubes and explicitly multidimensional ideas in favour of a simpler, relational model, and they told me that it’s because multidimensionality put a lot of people off; I can see that’s true – yes, a lot of people have been converted to the OLAP cause over the years, but we all know that many relational people just can’t stomach/understand SSAS today. The vast majority of people who use SSRS do so directly on relational sources, and as we know while there’s a great demand for things like Report Builder, Microsoft has had nothing that worked really well to enable end user reporting in SSRS; BISM, as I said, is aimed at solving this problem.