Chapter 1: Introduction

On This Page

Overview Overview
Intended Audience Intended Audience
Overview of Mainframe Migration Overview of Mainframe Migration
Resources and Skills Resources and Skills
Creating a Successful Windows Environment Creating a Successful Windows Environment
Contributors Contributors


This book is an introduction to enterprise computing capabilities offered by Microsoft® as compared to mainframe technology, and how the Microsoft Windows® platform can be an effective alternative to the mainframe environment. The goals are to provide an overview of the Microsoft enterprise platform including the Windows Server System™, the Windows development environment, and available prescriptive guidance and support relative to platform migration and subsequent operation.

The mainframe is traditionally assumed to be the most robust and powerful computing environment available to businesses. However, for businesses to stay competitive, it is important that the computing environment is not only powerful, but also provides the flexibility necessary to respond to rapid business change.

By migrating workloads from the mainframe to the Windows Server System™, an organization can increase performance and flexibility, while maintaining reliability and availability and substantially decreasing the cost of ownership. Customers can modernize legacy applications to take advantage of the new technologies and business opportunities provided by the Windows platform environment. Windows Server functionality has increased so rapidly in the past few years that many organizations are unaware of the benefits Windows now offers as a powerful, highly configurable, and manageable enterprise environment.

A migration is not a task that can be accomplished without proper planning. You must consider four approaches to mainframe migration when initiating this transition:

  • Integration. Moving one or more components of a mainframe application to the Windows platform.

  • Code Migration. Recompiling or converting the mainframe application source code to the Windows platform.

  • Replacement. Replacing existing mainframe applications with available Windows software packages.

  • Evolution. Utilizing the existing mainframe application as a functional specification and then rebuilding the application using Windows programming languages and tools.

Each of the preceding strategies is described in more detail in Chapter 8, "Mainframe Migration Fundamentals."

Note The term Windows is commonly used to describe the popular operating system (OS) from Microsoft. To properly understand the viability and capabilities of the Windows platform for enterprise computing, it is necessary to distinguish the Windows Server™, the Windows Server System, and the Windows Desktop:

  • Windows Server refers to the most current version of Windows designed to support enterprise computing. At the time of publication, this is Windows Server 2003.

  • Windows Server System collectively refers to Windows Server 2003 and the various Microsoft server products it supports, such as Microsoft SQL Server™ 2000, Microsoft Exchange Server, and Microsoft Host Integration Server.

  • Windows Desktop refers to the many versions of the OS found on personal computers, including Windows 2000 and Windows XP.

    For more information on the Windows Server System, refer to:

Intended Audience

The primary audiences for this book are information technology workers (IT), business decision makers (BDM), and IT technical decision makers (TDM). However, other technical specialists may also extract value from the content of this book. The following list describes the intended audiences for this guide.

  • IT business decision makers are responsible for understanding the business role of computing within the organization, as well as all associated development, administration and maintenance resources. This person understands IT costs, total cost of ownership (TCO) and return on investment (ROI) issues, but may not understand specific mainframe technology issues.

  • IT Technical Decision Makers are responsible for understanding the technical benefits, features, and usability of various information technologies. It is assumed that this person has an understanding of mainframe technology and is motivated to learn more about the Windows platform.

  • Technical and Solution Architects are responsible for network, security, database, and application architecture and design. These architects also have an in-depth understanding of their specialty within the organization, and are motivated to learn more about these subjects within the context of the Windows platform.

  • Mainframe Systems Programmers understand all technical support aspects of the installation. These programmers are also familiar with mainframe computer operations within the organization, mainframe performance, capacity management, and are motivated to learn more about these subjects within the context of the Windows platform.

  • Mainframe Operations Managers and Specialists are responsible for the day-to-day operational activities associated with the mainframe. These people understand the operation of mainframe systems and subsystems, including hardware configurations, any maintenance and support agreements with vendors, and any service level agreements that are in place.

Secondary audiences for this book include Windows professionals who are motivated to learn more about the mainframe environment.

Overview of Mainframe Migration

The information under the following headings describes the main issues discussed in this guide.

Why Migrate?

Mainframe installations have grown more complex and expensive, yet remain embedded at the center of many business environments because of the significant investment in application, skills, and data they represent. Many businesses are migrating from the mainframe to a more cost-effective and agile alternative to remain competitive.


Organizations seeking to implement a Service Oriented Architecture (SOA) or take advantage of emerging technologies such as Web services are often constrained by the mainframe. The majority of tools and techniques for accomplishing these things efficiently are not being developed for — or pioneered on — the mainframe, but they are being developed on the more modular and distributed environments designed by many vendors to support the Windows Server System.


A Windows solution presents significant cost savings when compared to a mainframe environment. Specifically, cost is lowered in terms of Million Instructions Per Second (MIPS); licensing fees; and the cost of hardware, such as Random Access Memory (RAM) and Direct-Access Storage Devices (DASD).

The cost savings associated with the Windows Server System are a direct result of competition, and not because of sacrificed features or functionality. The competitive forces that once existed in the mainframe market have virtually disappeared. Some vendors, such as Unisys and NEC, have refocused on the Windows and UNIX markets. Other vendors, such as Hitachi and Amdahl, have left the mainframe marketplace, essentially leaving IBM as the only vendor in the mainframe market. In contrast, the Windows market is highly competitive and includes hundreds of vendors.

Windows Server System operating costs are often similarly challenged and assumed to be missing important components. Microsoft has sponsored studies by Bearing Point, IDC, Meta Group, and Giga Research that show that Windows is anywhere from equal to 30 percent less costly to operate than Linux, the purported low cost champion and mainframe vendor's solution to high operating costs.

An independent TCO study currently available from the Yankee Group asserts that Windows is slightly less expensive to own and operate when compared to Linux. The deciding factors are the comparatively simple administration, lower software distribution costs, the competitive market in application software, and the availability of trained staff at reasonable cost.

This last factor is also important when comparing TCO between mainframe and Windows Server System environments. The technologies behind the mainframe environment are not the most current ones being taught in technical institutions. As a result, organizations utilizing the mainframe are typically faced with a more senior, and therefore more costly, IT payroll.


Whereas mainframe performance has only moderately increased over the past several years, possibly due to lack of competition in the mainframe market, the performance of platforms based on the Windows Server System has shown significant increase. For example, as of October 2004, the Transaction Processing Performance Council's TPC-C benchmark database shows that mainframes are completely absent from the more than 140 systems listed as being the best systems online transaction processing (OLTP) performance, the majority of which are based on the Windows Server System.

For more information on the TPC-C benchmark database, refer to:


By far, most research and product development in computing is being made in distributed computing environments, such as the Windows Server System. In addition, availability of the highly specialized skill set required in the mainframe environment is also diminishing. This decline not only severely limits the resources available to administer the mainframe, but also increases the costs of maintaining and developing those skills.

Much like Hewlett Packard's HP-UX and IBM's z/OS operating systems, Windows is proprietary software, in that the source code is copyrighted and only disclosed under contractual agreement to legitimate partners and licensees. However, the proprietary aspects of Windows do not extend to computing hardware.

Windows has always been an OS intended to be used on many different hardware platforms. This single attribute has revolutionized the personal computer industry. The adoption of almost any other proprietary OS also brings with it the constraint of being forced to use co-branded hardware and — to some extent — related systems software, such as Database Management Systems (DBMS) and Web servers. For example, if z/OS is adopted, it must run on IBM equipment; if Solaris, then Sun Microsystems equipment must be used.

The Window Server System does not impose these restrictions. In the hardware compatibility list for Windows Server, currently more than 230 server systems are available from dozens of different vendors, including Dell, Fujitsu-Siemens, Hewlett-Packard, Hitachi, IBM, Intel, Mitsubishi, NEC, Toshiba, Unisys, and many more. This means that Windows Server Systems must be extremely price-competitive and technologically innovative to succeed in the market.

Alternate Migration Destinations

Alternatives to the current mainframe exist besides the Windows platform. One such alternative is a larger and more powerful mainframe. Replacing a mainframe with a newer mainframe, however, merely postpones the issues driving migration away from mainframe systems.

Other alternatives often considered to replace the mainframe include WebSphere, Linux on the mainframe, and UNIX. Competitive evaluations of these alternatives are not within the scope of this book, although some commentary is appropriate to better understand the positioning of the Windows platform as a possible solution:

  • WebSphere represents a family of e-business-based server-side software infrastructure products. The various pieces of WebSphere run on multiple platforms, including Windows, UNIX, Linux, and the mainframe. As a result, organizations are able to run WebSphere on the platform that provides the best TCO. A central product in the WebSphere product line is the WebSphere Application Server, which adds another application execution environment to the mainframe for applications that adhere to Sun's J2EE specifications. Adopting WebSphere requires additional administration and management skills, as well as Java/J2EE programming skills.

  • Stand-alone Linux does not offer a true enterprise-level computing solution. On the mainframe, Linux can be run in a virtual machine, much like a logical partition. This option is usually suggested for organizations seeking to consolidate servers or use excess mainframe computing cycles. However, given that the value of Linux is most profound on commodity hardware, organizations should carefully investigate the financial viability of running Linux in a virtual machine on a mainframe.

  • UNIX is a mature alternative that has true enterprise capabilities, but this operating system has experienced some decline in popularity due largely to the emergence of Linux. Although commercial UNIX is a viable destination for migration, it is more expensive and lacks the vast selection of off-the-shelf software of the Windows Server System.

Resources and Skills

The subject of how migration affects people, their jobs, and responsibilities when migrating from mainframe environments is beyond the scope of this book. An evolution of skills is required, but new opportunities are also available to staff as a result of migration. The disciplines and processes required to successfully manage mainframe computing are still fundamentally the same in the Windows environment, and therefore remain valuable.

Creating a Successful Windows Environment

The Windows Server System is an integrated server infrastructure that is based on simplifying development, deployment, and management by anticipating business and technology needs and opportunities. It is designed to interoperate with other data and applications within an IT environment, reducing the cost of ongoing operations, and delivering a highly reliable and more secure infrastructure.

The Windows Server System is based on the Windows Server 2003 operating system and offers a variety of different products and technologies that provide operations, applications, and information infrastructures. Windows Server 2003 is available in the following editions:

  • Windows Server 2003, Standard Edition. For departmental and standard corporate workloads.

  • Windows Server 2003, Enterprise Edition. For critical or heavy server workloads.

  • Windows Server 2003, Datacenter Edition. For high levels of scalability and reliability.

  • Windows Server 2003, Web Edition. For Web serving and hosting.

The goal of the Windows Server System is to promote operational efficiencies through simplified deployment, management, and security; ensure high levels of dependability, performance, and productivity for application development; and seamlessly connect information, people, and systems.

A successful migration to the Windows platform results in a computing environment that satisfies the same criteria traditionally associated with successful mainframe installations:

  • High Reliability

  • Robust Security

  • High Performance

  • High Manageability

The following chapters provide an overview of how each of the preceding features is traditionally delivered in the mainframe environment; how the features are provided in the Windows Server System at either the same or higher level of service; tools available to achieve the desired service level; and references to additional resources from Microsoft or its partners.

Note Additional information is available from Microsoft to help organizations optimize a migration to the Windows Server System, including architectural guidance, well-defined processes and procedures and training options.

For more information on available Microsoft guidance, refer to Chapter 7: "Windows Production Environment" and Chapter 8: "Mainframe Migration Fundamentals."


Microsoft would like to acknowledge the contribution of Fujitsu Consulting to the creation of this guide.


David B. Runyan (Interop Systems)

Tatsuo Yamada (Interop Systems)


Thomas Olsen (Interop Systems)

Program Managers

Nicole Hess (Interop Systems)

Bill Miller (Interop Systems)

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Introduction to the Microsoft Enterprise Platform for Mainframe Professionals