The mainframe was the ultimate solution when it came to data consolidation. All data in an enterprise resided in one or several mainframes that were physically located in a data center. The rise of the hardware and software appliance has created a 'what is old is new again' situation; a hardware and software solution that is sold as one product. Oracle has released the Oracle Exadata appliance and IBM acquired the pure database warehouse appliance company Netezza, HP, and Microsoft announced work on an SQL Server database appliance, and even companies like SAP, EMC, and CICSO are talking about the benefits of database appliances.
The difference is (and it is a big difference) that the present architecture is based upon open standards hardware platforms, operating systems, client devices, network protocols, interfaces, and databases. So, you now have a database appliance that is not based upon proprietary operating systems, hardware, network components, software, and data...