Each z900 is capable of running literally thousands of separate instances of virtual Linux machines. So hosting a site on a dedicated server becomes not a matter of hardware but of software. That speeds up the process of bringing up a site considerably. This ability to divide and host leads to a number of advantages. Wanish notes that mainframes are highly reliable, with built-in redundancies from chips to power supplies.
Mainframes are also highly scalable.
The ability to host many virtual Linux boxes leads to the ability to slice processor time to fit tiny tasks. A Web site that only gets a few hits, such as a personal home page or that of a small business, can be served with only part of the mainframe s power. Sites with more hits can be handled by turning more of the mainframe s attention to the task. Such scalability results in some unforeseen economic advantages. The Boston-based Hurwitz Group did an analysis earlier this year of the energy consumption of a server farm and a mainframe.