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The Genesis of AIR > Legacy Era

Legacy Era

Computers have played a role in the business environment for nearly five decades. Between their introduction to business in the late 1950s, until the heyday of the Internet era (late 1990s), there has been a fluctuation between centralizing processing power on one or a cluster of servers and distributing the processing across the clients.

Mainframe Era

While there were dozens of computers produced and used before 1955, much of that usage was limited to military and other governmental organizations. The true age of business computing seems to have started in 1955, when the IBM 704 was the first commercially available computer system. This started the age of mainframe computing, in which all processing power was centralized in a powerful, centralized machine. Throughout the mainframe era, there were a number of improvements, such as the addition of terminals, spread throughout the business, which could allow multiple users to simultaneously connect and interact with the mainframe; however, all the processing power continued to remain at the server, with the terminals simply being a tool to allow users to view and interact with that data.


Over the years, as memory and processing power became cheaper and more available, the microcomputer (sometimes referred to as the personal computer) began to emerge. These computers had the resources to run stand-alone applications, and soon most business needs could be handled from the desktop, as opposed to requiring the use of the mainframe. Another benefit of microcomputers was that they were frequently easier to use, as user interfaces continued to improve (it was during the age of the microcomputer that graphical user interfaces [GUIs] were first commercially available). While microcomputers offered many improvements, they specifically lacked some of the best features of the mainframe era, in that there was little or no centralization of data, nor of business rules.


The paradigm shift from mainframes to microcomputers solved many issues, but, as previously mentioned, it created a series of new problems. Responding to these issues, a number of software vendors began designing solutions that harnessed both benefits of a centralized server with the power of the desktop computer. This led to the birth of the client/server era. These applications usually had one or more powerful centralized servers, which stored the application data and housed all the business rules, and a number of independent desktop clients, each running an easy-to-use interface (often a GUI). This style of application was immensely useful to the business community, taking the greatest benefits and mitigating the greatest weaknesses of both the mainframe and microcomputer era. However, a weakness the client/server applications shared with the microcomputer era became far more apparent—distribution; it was extremely difficult to keep a vast number of clients up-to-date. As large businesses sought to update the software on hundreds or thousands of individual desktops, they found that a large staff was required to merely keep each machine up-to-date.

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