Microsoft SQL Server 2008 Analysis Services Unleashed Book Review Chapter 14
This chapter shows how to extend the native commands within Analysis Services using either managed code assemblies or COM assemblies. I will assume knowledge of assembly creation with either COM or .NET languages, since that assumption follows how this chapter is presented. I realize that this assumption will leave out some people from understanding this chapter.
As has been true for years, COM assemblies are (as a rule) less secure than managed assemblies, and therefore the wisdom is to rewrite any COM assemblies in .NET. I concede that there are still COM developers who can write effective code, but going forward, I recommend using one of the many .NET languages to write any code. COM support is turned off by default (page 245) as an extra security precaution.
Data Mining with Microsoft SQL Server 2008