IBM and the resurrection of the mainframe | Outside the Lines - CNET News.com

A timely snapshot

As proof of its mainframe devotion, IBM is in the process of internally replacing 3,900 servers with 33 mainframes by the end of 2009, he added, noting that issues such as data center space and energy savings make the mainframe a cost-effective investment. Since 2000, units of installed mainframe capacity from all vendors has grown from 4 million to almost 13 million today, Zeitler said.

Mills dismissed the idea that Salesforce.com, NetSuite and others running enterprise applications are fully multitenant, meaning they run multiple customers with a single application and database instance with data isolation across a distributed network of servers and virtual machines. "This is a topic of much illusion. You can't change the laws of physics. Don't let anyone tell you that they have found the Holy Grail of multitenancy. Few will let you in to see if it is fully multitenant," he said.

IBM and the resurrection of the mainframe | Outside the Lines - CNET News.com