of terminal-to-host connectivity. At the bottom of the heap were smart terminals; a group of these ter- minals would report to an upper-level manager, often referred to as a cluster con- troller. The cluster controller was responsible for managing the traffic flows in and out of its underlying terminals and for scheduling resources upstream from those terminals. In turn, a number of cluster controllers would be managed by yet another level of manager, called the front-end processor, which served as the inter- face between the underlying communications network and the applications stored in the host. That front-end processor ultimately led to the host, where the users' applications resided. In that era, a given terminal could have access only to the host upstream from it. To make use of applications that resided on another host, a user either needed a different terminal or had the pleasure of working with a variety of cables under his or her desk, changing the connections as needed. The Evolution of Data Communications Networked Mainframes A major change occurred in the early 1980s: People began networking the main- frames. This was called multidomain networking, and it enabled one terminal device on a desktop to access numerous hosts that were networked together. Standalone Workstations Also in the early 1980s, standalone workstations began to appear in the enterprise. This did not generally happen because the data-processing department had decided that it would move to workstations; rather, it happened because technically astute users began to bring their own workstations into the firm, and then they would ask the data-processing or management information services (MIS) department to allow connectivity into the corporate resources from their workstations, which was gen- erally accommodated via dialup modems or X.25. As independent workstations began to penetrate the corporate environment, peo- ple started to study how data was actually being used. They found that 80% of the information used in a business was com