The IT infrastructure in organizations today is an outgrowth of around 90 years of evolution in computing platforms. We have identified six stages in this evolution, each representing a different configuration of computing power and infrastructure elements. The six eras are automated special-purpose machines, general-purpose mainframe and minicomputer computing, personal computers, client/server networks, enterprise and Internet computing, and cloud & mobile computing.
ELECTRONIC ACCOUNTING MACHINE ERA: 1930–1950
The first era of business computing used specialized machines that could sort computer cards into bins, accumulate totals, and print reports. Although the electronic accounting machine was an efficient processor of accounting tasks, the machines were large and cumbersome. Software programs were hardwired into circuit boards, and they could be changed by altering the wired connections on a patch board. There were no programmers, and a human machine operator was the operating system, controlling all system resources.
GENERAL-PURPOSE MAINFRAME AND MINICOMPUTER ERA: 1959 TO PRESENT
The first commercial all-electronic vacuum tube computers appeared in the early 1950s with the introduction of the UNIVAC computers and the IBM 700 Series. Not until 1959 with the introduction of the IBM 1401 and 7090 transistorized machines did widespread commercial use of mainframe computers begin in earnest. In 1965, the general-purpose commercial mainframe computer truly came into its own with the introduction of the IBM 360 series. The 360 was the first commercial computer with a powerful operating system that could provide time sharing, multitasking, and virtual memory in more advanced models.
Mainframe computers eventually became powerful enough to support thousands of online remote terminals connected to a centralized mainframe using proprietary communication protocols and proprietary data lines.
The mainframe era was a period of highly centralized computing under the control of professional programmers and systems operators (usually in a corporate data center), with most elements of infrastructure provided by a single vendor, the manufacturer of the hardware and the software. This pattern began to change with the introduction of minicomputers produced by Digital Equipment Corporation (DEC) in 1965. DEC minicomputers (PDP-11 and later the VAX machines) offered powerful machines at far lower prices than IBM mainframes, making possible decentralized computing, customized to the specific needs of individual departments or business units rather than time sharing on a single huge mainframe.
PERSONAL COMPUTER ERA: (1981 TO PRESENT)
Although the first truly personal computers (PCs) appeared in the 1970s (the Xerox Alto, MIT’s Altair, and the Apple I and II, to name a few), these machines had only limited distribution to computer enthusiasts. The appearance of the IBM PC in 1981 is usually credited as the beginning of the PC era because this machine was the first to become widely adopted in American businesses. At first using the DOS operating system, a text-based command language, and later the Microsoft Windows operating system, the Wintel PC computer (Windows operating system software on a computer with an Intel microprocessor) became the standard desktop personal computer.
Proliferation of PCs in the 1980s and early 1990s launched a spate of personal desktop productivity software tools—word processors, spreadsheets, electronic presentation software, and small data management programs—that were very valuable to both home and corporate users. These PCs were standalone systems until PC operating system software in the 1990s made it possible to link them into networks.
CLIENT/SERVER ERA (1983 TO PRESENT)
In client/server computing, desktop or laptop computers called clients are networked to server computers that provide the client computers with a variety of services and capabilities. Computer processing work is split between these two types of machines. The client is the user point of entry, whereas the server provides communication among the clients, processes and stores shared data, serves up Web pages, or manages network activities. The term server refers to both the software application and the physical computer on which the network software runs. The server could be a mainframe, but today server computers typically are more powerful versions of personal computers, based on inexpensive Intel chips and often using multiple processors in a single computer box.
The simplest client/server network consists of a client computer networked to a server computer, with processing split between the two types of machines. This is called a two-tiered client/server architecture. Whereas simple client/server networks can be found in small businesses, most corporations have more complex, multitiered (often called N-tier) client/server architectures in which the work of the entire network is balanced over several different levels of servers, depending on the kind of service being requested.
Novell Netware was the leading technology for client/server networking at the beginning of the client/server era. Today Microsoft is the market leader, with its Windows operating systems.
ENTERPRISE INTERNET COMPUTING ERA (1992 TO PRESENT)
The success of the client/server model posed a new set of problems for corporations. Many large firms found it difficult to integrate all of their local area networks (LANs) into a single, coherent corporate computing environment. Applications developed by local departments and divisions in a firm, or in different geographic areas, could not communicate easily with one another and share data.
In the early 1990s, firms turned to networking standards and software tools that could integrate disparate networks and applications throughout the firm into an enterprise-wide infrastructure. As the Internet developed into a trusted communications environment after 1995, business firms began using the Transmission Control Protocol/ Internet Protocol (TCP/IP) networking standard to tie their disparate networks together.
The resulting IT infrastructure links different types and brands of computer hardware and smaller networks into an enterprise-wide network so that information can flow freely across the organization and between the firm and other organizations. Enterprise networks link mainframes, servers, PCs, mobile phones, and other handheld devices, and connect to public infrastructures such as the telephone system, the Internet, and public network services.
Cloud and Mobile Computing Era (2000 to Present)
The growing bandwidth power of the Internet has pushed the client/server model one step further, towards what is called the “Cloud Computing Model.” Cloud computing refers to a model of computing that provides access to a shared pool of computing resources (computers, storage, applications, and services) over a network, often the Internet. These “clouds” of computing resources can be accessed on an as-needed basis from any connected device and location.
Haradhan Chattaraj is the Founder, Designated Partner and Head – Infrastructure Services of Luscinia Consulting LLP. He can be reached at haradhan.chattaraj@lusciniaconsulting.com.