Evolution of IT Infrastructure

The IT infrastructure in organizations today is an outgrowth of more than 50 years of evolution in computing platforms. There have been five stages in this evolution, each representing a different configuration of comput­ing power and infrastructure elements (see Figure 5.2). The five eras are general-purpose mainframe and minicomputer computing, personal com­puters, client/server networks, enterprise computing, and cloud and mobile computing.

Technologies that characterize one era may also be used in another time period for other purposes. For example, some companies still run traditional mainframe systems or use mainframe computers as servers supporting large websites and corporate enterprise applications.

1. General-Purpose Mainframe and Minicomputer Era (1959 to Present)

The introduction of the IBM 1401 and 7090 transistorized machines in 1959 marked the beginning of widespread commercial use of mainframe comput­ers. In 1965, the mainframe computer truly came into its own with the in­troduction of the IBM 360 series. The 360 was the first commercial computer that could provide time sharing, multitasking, and virtual memory in more ad­vanced models. IBM has dominated mainframe computing from this point on.

Mainframe computers became powerful enough to support thousands of online remote terminals connected to the 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. In recent years, the minicom­puter has evolved into a midrange computer or midrange server and is part of a network.

2. Personal Computer Era (1981 to Present)

Although the first truly personal computers (PCs) appeared in the 1970s (the Xerox Alto, the MITS Altair 8800, 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 considered the beginning of the PC era because this machine was the first to be widely adopted by 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. Worldwide PC sales have declined be­cause of the popularity of tablets and smartphones, but the PC is still a popular tool for business. Approximately 88 percent of desktop PCs are thought to run a version of Windows, and about 8 percent run a version of MacOS. Wintel domi­nance as a computing platform is receding as iPhone and Android device sales increase.

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 stand-alone systems until PC operating system software in the 1990s made it possible to link them into networks.

3. Client/Server Era (1983 to Present)

In client/server computing, desktop or laptop computers called clients are networked to powerful 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 typically 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 chips and often using multiple processors in a single computer box or in server racks.

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 client/server architectures (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 (see Figure 5.3).

For instance, at the first level, a web server will serve a web page to a cli­ent in response to a request for service. Web server software is responsible for locating and managing stored web pages. If the client requests access to a cor­porate system (a product list or price information, for instance), the request is passed along to an application server. Application server software handles all application operations between a user and an organization’s back-end business systems. The application server may reside on the same computer as the web server or on its own dedicated computer.

Client/server computing enables businesses to distribute computing work across a series of smaller, inexpensive machines that cost much less than cen­tralized mainframe systems. The result is an explosion in computing power and applications throughout the firm.

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 (Windows Server, Windows 10, Windows 8, and Windows 7).

4. Enterprise Computing Era (1992 to Present)

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 seri­ously using the Transmission Control Protocol/Internet Protocol (TCP/IP) net­working standard to tie their disparate networks together. We discuss TCP/IP in detail in Chapter 7.

The resulting IT infrastructure links different pieces 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. It can link different types of computer hardware, including mainframes, servers, PCs, and mobile devices, and it includes public infra­structures such as the telephone system, the Internet, and public network services. The enterprise infrastructure also requires software to link disparate applications and enable data to flow freely among different parts of the busi­ness, such as enterprise applications (see Chapters 2 and 9) and web services (discussed in Section 5-4).

5. Cloud and Mobile Computing Era (2000 to Present)

The growing bandwidth power of the Internet has pushed the client/server model one step further, toward 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 the network, often the Internet. These “clouds” of computing re­sources can be accessed on an as-needed basis from any connected device and location.

Cloud computing bas become the fastest-growing form of computing, with worldwide public cloud spending to reach $411 billion by 2020. Cisco Systems predicts that 94 percent of all computer workloads will run in some type of cloud environment by 2021 (Gartner, 2017; Cisco 2018).

Thousands or even hundreds of thousands of computers are located in cloud data centers, where they can be accessed by desktop computers, laptop com­puters, tablets, entertainment centers, smartphones, and other client machines linked to the Internet. Amazon, Google, IBM, and Microsoft operate huge, scal­able cloud computing centers that provide computing power, data storage, application development tools, and high-speed Internet connections to firms that want to maintain their IT infrastructures remotely. Firms such as Google, Microsoft, SAP, Oracle, and Salesforce.com sell software applications as services delivered over the Internet.

We discuss cloud and mobile computing in more detail in Section 5-3. The Learning Tracks include a table titled “Comparing Stages in IT Infrastructure Evolution,” which compares each era on the infrastructure dimensions introduced.

Source: Laudon Kenneth C., Laudon Jane Price (2020), Management Information Systems: Managing the Digital Firm, Pearson; 16^th edition.