As server consolidation picks up and users turn to mainframe- class Unix systems to centralize application serving and data processing, Hewlett-Packard Co says the single biggest issue it faces in convincing users to buy Unix systems of this kind is the cost of software licenses. Potential customers of these systems, which include HP’s V-Class servers, are balking at the cost of buying new applications – or upgrading existing software licenses – to run on this class of machine. Many software companies depend heavily on revenue from sales of mainframe-class system licenses and are said to be largely unwilling to change their pricing models. Software vendors have traditionally priced mainframe versions of applications according to how powerful, or how many MIPS a system can perform. The type of user HP is seeking to consolidate around a Unix data center is typically running applications on multiple, distributed systems at the moment. Customers buy a site or corporate license from the software vendor that enables a specific number of users to run the software rather than paying according to how big the system itself is. Competition and volumes mean these applications, usually running on department or groupware servers, cost much less than mainframe licenses even if a similar number of users can access them. HP is trying to encourage mainframe ISVs to charge for site or corporate licenses rather than by performance.