Chapter 4: Assessment and Analysis

Introduction

The process of migrating UNIX software to Microsoft Windows 2000 is sometimes perceived to be a long, expensive undertaking because of incompatibilities between the two operating systems. However, application migration from UNIX to Windows is feasible , and this chapter will help guide you through the process.

To migrate an application from UNIX to Windows, you must consider the platform differences, the differences between the application s implementation on each platform, and the features of the deployment and management tools available for each operating environment. Therefore, any application migration from UNIX to Windows requires a thorough assessment of the application to be migrated , followed by an analysis to determine the most appropriate migration approach.

This chapter discusses the assessment and analysis aspects of the migration process in detail, including:

• Gathering data.

• Evaluating the migration objectives.

• Evaluating the application.

• Defining the migration strategy.

In addition, this chapter examines the specific migration strategies for various application architectures, including workstation-based applications and server-based applications.

Planning

The results of the assessment and analysis phase are used to develop the various migration plans ”for example, development, testing, training, deployment, and support. These results also act as input to risk assessment activities, which are a mainstay of both planning and testing. The assessment and analysis phase therefore requires planning, which includes:

• Scoping the assessment, the analysis, and the migration.

• Identifying data sources.

• Arranging interviews and workshops.

The assessment and analysis phase follows the law of diminishing returns; that is, the value that it provides diminishes relative to effort. It is therefore important to size these activities according to the size of the migration.

Assumptions

This chapter focuses on software that is written in the C, C++, and Fortran compiled languages, in addition to scripting languages such as Perl and various UNIX shells (for example, Bourne, Korn, C, and Bash). This chapter assumes that the application s UNIX-based source code is available in either an archive or source control system, such as the following:

• Concurrent Version System (CVS)

• Revision Control System (RCS)

• Program Version Control System (PVCS)

Some migrations will result in the subsequent removal of the UNIX environment. However, many environments will need Windows to integrate (and coexist) with UNIX, and to run the same migrated application software that is currently running on the UNIX platform or platforms. The need for coexistence is an important factor in software migrations. A migration philosophy that takes into account cross-platform software portability allows Windows to be accepted in organizations that require the application to remain on the existing UNIX platform or platforms.

Time to market is just as important for internal applications as it is for independent software vendor (ISV) software. Applications often represent competitive advantages to their owners (for example, augmentations to computer-aided engineering analysis or product data management packages). A software migration philosophy must accommodate this urgency for the migration project to be successful based on time and resource constraints.