Operational economy Firms have moved back to mainframes partly because of the potential for high availability and good scalability, but also for savings in operational costs. Mainframes are expensive to buy, but they only require small support teams and offer very fast application upgrades, managed from a single point. There are sometimes value-added features too, such as capacity upgrade on demand. An upgrade installed with the flick of a switch can be very useful in e-business, where peak demands can be huge, and hard to predict. This is doubly true if the customer does not have to pay for the extra capacity until it is used.
Mainframes do have drawbacks for implementation in e-business environments.
Firms may have to provide offsite storage facilities, highly specified hot-site recovery facilities, and so on, to guarantee availability. Mainframe technology supports this well, but it has to be planned carefully. Although mainframes scale up well, there comes a point when the mainframe runs out of capacity. Adding another increment of mainframe is not quite like firing up another PC server, it needs careful planning and significant expenditure. In a mainframe world, staff need to have the expertise to think about capacity planning and so on.