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Evolution of IT Infrastructure: 1950–2005 The IT infrastructure in organizations today is an outgrowth of over 50 years of evolu- tion in computing platforms. We have identified five stages in this evolution, each repre- senting a different configuration of computing power and infrastructure elements (see Figure 4-1). The five eras are automated special-purpose machines, general-purpose mainframe and minicomputer computing, personal computers, client/server networks, and enterprise and Internet computing.

These eras do not necessarily end for all organizations at the same time, and the tech- nologies that characterize one era may also be used in another time period for other pur- poses. For example, some companies still run traditional mainframe or minicomputer systems. Mainframe computers today are used as massive servers supporting large Web sites and corporate enterprise applications. More detail on infrastructure history can be found on the Laudon Web site for Chapter 6.

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 (DaCruz, 2004). Although the elec- tronic 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 com- munication protocols and proprietary data lines. The first airline reservation systems appeared in 1959 and became the prototypical online, real-time interactive computing system that could scale to the size of an entire nation.

IBM dominated mainframe computing from 1965 onward and still dominates this $27 billion global market in 2004. Today IBM mainframe systems can work with a wide vari- ety of different manufacturers’ computers and multiple operating systems on client/ serv- er networks and networks based on Internet technology standards.

Chapter 4 IT Infrastructure: Hardware and Software 1 LEARNING TRACK 5: THE EVOLUTION OF IT INFRASTRUCTURE CHAPTER 4: Learning Track 52 FIGURE 4-1Eras in IT infrastructure evolution.

Illustrated here are the typical computing configurations char- acterizing each of the five eras of IT infrastructure evolution. CHAPTER 4: Learning Track 13 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 mini- computers produced by Digital Equipment Corporation (DEC) in 1965. DEC minicom- puters (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. Today, 95 percent of the world’s estimated 1 billion computers use the Wintel standard.

Proliferation of PCs in the 1980s and early 1990s launched a spate of personal desk- top 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 soft- ware 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 com- puter 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 serv- er 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 bal- anced over several different levels of servers, depending on the kind of service being requested (see Figure 4-2).

For instance, at the first level a Web server will serve a Web page to a client in response for 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 prod- uct 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 number of smaller, inexpensive machines that cost much less than minicomputers or cen- tralized mainframe systems. The result is an explosion in computing power and applica- tions throughout the firm. CHAPTER 4: Learning Track 53 CHAPTER 4: Learning Track 54 Novell Netware was the leading technology for client/server networking at the begin- ning of the client/server era. Today Microsoft is the market leader, with its Windows operating systems (Windows Server, Windows XP, Windows 2000), controlling 78 per- cent of the local area network market. 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 net- works 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.

The enterprise infrastructure employs software that can link disparate applications and enable data to flow freely among different parts of the business. Other solutions for enterprise integration include enterprise application integration software, Web services, and outsourcing to external vendors that provide hardware and software for a compre- hensive enterprise infrastructure.

The enterprise era promises to bring about a truly integrated computing and IT serv- ices platform for the management of global enterprises. The hope is to deliver critical business information painlessly and seamlessly to decision makers when and where they need it to create customer value. This could be everything from getting inventory data to the mobile salesperson in the customer’s office, to helping a customer at a call center FIGURE 4-2A multitiered client/server network (N-tier).

In a multitiered client/server network, client requests for service are handled by different levels of servers. with a problem customer, or providing managers with precise up-to-the-minute infor- mation on company performance.

That is the promise, but the reality is wrenchingly difficult and awesomely expensive.

Most large firms have a huge, tangled web of hardware systems and software applica- tions inherited from the past. This makes achieving this level of enterprise integration a difficult, long-term process that can last perhaps as long as a decade and cost large com- panies hundreds of millions of dollars. Table 4-1 compares each era on the infrastructure dimensions discussed above. CHAPTER 4: Learning Track 55 TABLE 4-1Stages in the IT Infrastructure Evolution Electronic Accounting Client/Server Machine Era Mainframe Era PC Era Era (1983 Enterprise Era Infrastructure Dimension (1930–1950) (1959 to Present) (1981 to Present) to Present) (1992 to Present) Signature Firm(s)IBM IBM Microsoft/Intel Novell SAP Burroughs Dell Microsoft Oracle NCR HP PeopleSoft IBM Hardware PlatformProgrammableCentralized Wintel computers Wintel Multiple:

card sorters mainframe computers • Mainframe Server Client Operating SystemHuman IBM 360 DOS/Windows Windows 3.1 Multiple: operators IBM 370 Linux Windows Unix/Linux Unix IBM 390 Server OS 390 Linux Windows Server Application and None; Few enterprise-wide No enterprise Few Enterprise-wide Enterprise Softwareapplication applications; connectivity; enterprise-wide applications linked software departmental boxed software applications; to desktop and created by applications created boxed software departmental technicians by in-house applications for applications:

programmersworkgroups and mySAP departments Oracle E-Business Suite PeopleSoft Enterprise One Networking/None Vendor-provided: None or limitedNovell NetWare L AN Telecommunications Systems Network Windows 2003 Enterprise-wide Architecture (IBM)Linuxarea network (WAN) DECNET (Digital) AT&T voice TCP/IP Internet AT&T voice standards-enabled System IntegrationVendor- Vendor-provided NoneAccounting and Software provided consulting manufacturer firms Accounting and Service firms consulting firms System integration firms Service firms CHAPTER 4: Learning Track 56 Data Storage and Physical card Magnetic storage DBase II and III Multiple Enterprise database Database Managementmanagement Flat files Access database servers Relational servers with databases optical and magnetic storage Internet PlatformsNone Poor to none None at first None at first None in the early Later browser- Later: years enabled clients Apache Later:

server Intranet- and Microsoft IISInternet-delivered enterprise services Large server farms