Windows 2000 Performance Guide

Problems of Scale

As fast as hardware is improving, it still cannot always meet user expectations. Computer applications are growing more intelligent and easier to use. However, because of this, they also require more resources to run. Additionally, computer applications are being deployed to more and more people living in every part of the world. This inevitably leads to problems of scale: applications may run all right in development, but run in fits and starts when you start to deploy them on a widespread basis.

Problems of scalability are some of the most difficult that application developers face. There are three facets to scalability:

• The problems computers must solve get characteristically more difficult to compute as the number of elements involved grows.

• People often have unrealistically high expectations about what computer technology can actually do.

• There are sometimes absolute physical constraints on performance that cannot be avoided. This applies to long-distance telecommunications as much as it does to signal propagation inside a chip or across a communications bus.

We discuss these three factors in the following sections.

Software Scalability

There are “hard” problems for computers that have a way of getting increasingly more complicated as the problem space itself grows larger. A classic example is the traveling salesman problem, where the computer calculates the most efficient route through multiple cities. This can be accomplished by brute force with a small ...