Last month, Microsoft released the public beta of Exchange 2010, which is due by year's end. At the time, it unveiled a number of flashy end-user features .

At the Tech Ed conference in Los Angeles, a Microsoft developer detailed a handful of back-end improvements in Exchange Server 2010. All address performance and scalablity, which has long been a sore point for Exchange administrators and users, with Exchange's Jet database engine taking much of the blame.

Several years ago, Microsoft announced a plan to move Exchange to a SQL Server-based database engine, but later abandoned it.

While keeping Jet for Exchange 2010, Microsoft changed its storage schema such that reading and writing mails to disk will be smoother and less bursty, according to Ross Smith IV, a senior technology architect for Microsoft.

That will result in a 70% I/O improvement over Exchange 2007, and 90% improvement over Exchange 2003, he said.