Home > Store

Modernizing Legacy Systems: Software Technologies, Engineering Processes, and Business Practices

Register your product to gain access to bonus material or receive a coupon.

Modernizing Legacy Systems: Software Technologies, Engineering Processes, and Business Practices

Book

  • Sorry, this book is no longer in print.
Not for Sale

Description

  • Copyright 2003
  • Dimensions: 6-1/4" x 9-1/4"
  • Pages: 352
  • Edition: 1st
  • Book
  • ISBN-10: 0-321-11884-7
  • ISBN-13: 978-0-321-11884-4

Most organizations rely on complex enterprise information systems (EISs) to codify their business practices and collect, process, and analyze business data. These EISs are large, heterogeneous, distributed, constantly evolving, dynamic, long-lived, and mission critical. In other words, they are a complicated system of systems. As features are added to an EIS, new technologies and components are selected and integrated. In many ways, these information systems are to an enterprise what a brain is to the higher species--a complex, poorly understood mass upon which the organism relies for its very existence. To optimize business value, these large, complex systems must be modernized--but where does one begin? This book uses an extensive real-world case study (based on the modernization of a thirty year old retail system) to show how modernizing legacy systems can deliver significant business value to any organization.

Sample Content

Online Sample Chapter

Risk-Managed Modernization of Legacy Systems

Downloadable Sample Chapter

Click below for Sample Chapter(s) related to this title:
Sample Chapter 3

Table of Contents



Preface.


1. The Legacy Crisis.

Modernization Challenges.

Complexity.

Software Technology and Engineering Processes.

Risk.

Commercial Components.

Business Objectives.

How Did We Get Here?

The Legacy Crisis.

Evolving Legacy Systems.

Maintenance.

Modernization.

Replacement.

Software Reengineering.

Retargeting.

Revamping.

Commercial Components.

Source Code Translation.

Code Reduction.

Functional Transformation.

Incremental Development and Deployment.

Summary.

For Further Reading.



2. The Beast.

The Retail Supply System.

Database.

User Interface.

Transactions.

Recent History.

Web Enablement.

Reports.

Summary.



3. Risk-Managed Modernization.

Risk Management.

Portfolio Analysis.

Identify Stakeholders.

Understand Requirements.

Create the Business Case.

Understand the Legacy System.

Understand Existing Software Technologies.

Evaluate Technology.

Define Target Architecture.

Define Modernization Strategy.

Reconcile Modernization Strategy with Stakeholders.

Estimate Resources for Modernization Strategy.

Summary.



4. Developing the Business Case.

Where Are We?

Identify Stakeholders.

Understand Requirements.

Requirements.

Constraints.

RSS Requirements.

New Functionality.

Architecture Compliance.

Incremental Development and Deployment.

Modernization Goals.

Create a Business Case.

General Structure and Contents.

Incremental Modernization.

The RSS Business Case.

Problem Statement.

Solution.

Risks.

Benefits.

Summary.

For Further Reading.



5. Understanding the Legacy System.

Where Are We?

The Context for Program Understanding: The Horseshoe Model.

Code Transformations.

Functional Transformations.

Architectural Transformations.

Reconstruction.

Code-Structure Representation.

Function-Level Representation.

Architecture-Level Representation.

Architecture Reconstruction.

Issues.

Tool Support versus Manual Effort.

Decompilation/Disassembly.

Summary.

For Further Reading.



6. Architecture Representation.

Where Are We?

Purpose of Architecture Representation.

Architecture Representation Requirements.

Views of the System.

Levels of Granularity.

Architectural Views.

Module Views.

Component-and-Connector Views.

Deployment View.

Additional Considerations.

System Context.

Hybrid Views.

Summary.

For Further Reading.



7. Languages and Data Management.

Where Are We?

COBOL.

History.

General Structure.

Arithmetic.

Variables.

Calling and Parameter Passing.

Composing Source Files.

Obsolete Language Features.

Standards.

Products.

Java.

History.

General Structure.

The Java Platform.

Characteristics of the Java Language.

Types of Java Programs.

Java Application Programming Interfaces (APIs).

Products.

Data Repositories.

Database Management Systems.

Data Warehouses.

Standards.

Products.

Data Representations for Information Exchange.

EDI.

XML.

Standards.

Products.

Summary.



8. Transaction Technology.

Where Are We?

Distributed Communication.

Transactions.

Flat Transactions.

Flat Transactions with Save Points.

Chained Transactions.

Closed Nested Transactions.

Open Nested Transactions.

Multilevel Transactions.

Distributed-Access Transactions.

Distributed Transactional Operations.

Distributed-Transaction Model.

Resource Manager Component.

Communication Resource Manager Component.

Transaction Manager Component.

Application Components.

Queued-Transaction Model.

Comparison of Transactional Models.

Standards.

Products.

Summary.



9. Software Infrastructure.

Where Are We?

Enterprise JavaBeans.

Enterprise JavaBean Types.

Persistence for Entity Beans.

Support for Transactions.

Security.

Products.

Message-Oriented Middleware.

Messages.

Queues.

Queue Manager.

Triggers.

Message Queue Interface.

Transaction Support.

Products.

Java 2 Enterprise Edition.

J2EE Services.

Deployment.

XML Messaging.

XML Messaging Components.

BizTalk.

Electronic Business XML.

Open Applications Group Integration Specification.

RosettaNet.

How These Standards Relate.

Other Standards Related to XML Messaging.

Summary.



10. Maintaining Transactional Context.

Where Are We?

Model Problem: Retail Supply System.

Contingency Planning.

MQSeries.

Object Transaction Service.

Oracle Pro*Cobol.

Net Express.

Definition of the Model Problem.

Solution of the Model Problem.

Design of the Model Solution.

Building the Test Adapter.

Evaluation.

Summary.



11. Business Object Integration.

Where Are We?

A Tale of Two Architectures.

J2EE Architecture.

B2B Architecture.

Quality Attributes.

Performance.

Security.

Availability.

Data Integrity.

Modifiability.

Portability.

Reusability.

Integrability.

Summary.



12. Target Architecture.

Where Are We?

Forces Affecting the Architecture.

Data Requirements.

Organizational Requirements.

Technology Requirements.

Overview of the Architecture.

Application Components.

Business Objects.

Service Components.

Data Components.

Wrapper Components.

BSR Interface.

Architectural Patterns.

Data Access Involving One Business Object.

Data Access Involving More Than One Business Object.

Report.

Ad Hoc Query.

Roll-Ups.

Batch Roll-Up.

Continuously Updated Roll-Up.

Transactions.

Data Warehouses.

Summary.



13. Architecture Transformation.

Where Are We?

Data Adapters.

Data Replication.

Data-Access Layer.

Database Gateway.

Hybrids.

Comparison.

Logic Adapters.

Object-Oriented Wrapping.

Component Wrapping.

Comparison.

Architecture Transformation Strategy.

Code Migration.

Data Migration.

Deployment Strategy.

Componentization Trail Maps.

Use of Adapters in RSS.

Summary.



14. System Preparation.

Where Are We?

Analysis of Alternatives.

Plan 1: DMS on OS 2200.

Plan 2: RDMS on OS 2200.

Plan 3: Oracle on the Solaris Platform.

Plan 4: Everything on the Solaris Platform.

Plan 5: Everything on Solaris+.

Evaluation of Alternatives.

Summary.



15. Code and Data Migration.

Where Are We?

Structural Analysis.

Initial Plan.

Revised Plan.

Code Migration Plan.

Data Migration Plan.

Summary.



16. Integrated Plan.

Where Are We?

Reconciliation Objectives.

Reconciliation Plan.

Stakeholder Priorities.

User Representatives.

Architecture Team.

Legacy System Maintainers.

Management.

Observations.

Stakeholder Ideal Profiles.

User Representatives.

Architecture Team.

Legacy System Maintainers.

Management.

Stakeholder Consensus Meetings.

Code-Migration Prioritization Results.

Summary.



17. Resource Estimation.

Where Are We?

Cost Estimation Overview.

Function-Based Estimation.

Task-Based Estimation.

Costing an Increment.

Legacy System Size.

Adapters.

Maintenance Costs.

Growth Factor.

Estimation of Cost and Duration.

Productivity Ratio Approach.

Cost Estimation Models.

Costing the Preparation Work.

Costing the Final Database Migration.

Data Collection.

Summary.

For Further Reading.



18. Recommendations.

Find a Better Way.

Use Commercial Components.

Manage Complexity.

Develop and Deploy Incrementally.

Software Engineering Skills.

Component-Centric Approach.

Architecture-Centric Approach.

High Levels of Concurrent Development.

Continuous Integration.

Risk-Managed Development.

Final Word.



References.


Acronyms.


Index. 0321118847T01242003

Preface

Software systems become legacy systems when they begin to resist modification and evolution. However, the knowledge embodied in legacy systems constitutes significant corporate assets. Assuming these system still provide significant business value, they must then be modernized or replaced. This book describes a risk-managed approach to legacy system modernization that applies a knowledge of software technologies and an understanding of engineering processes within a business context.

Audience

Modernizing Legacy Systems: Software Technologies, Engineering Processes and Business Practices should be useful to anyone involved in modernizing a legacy system.

  • As a software engineer, it should help you understand some of the larger business concerns that drive a modernization effort.
  • As a software designer, this book should help you understand the impact of legacy code, coupled with incremental development and deployment practices, on design activities.
  • As a system architect, this book explains the processes and techniques that have failed or succeeded in practice. It should also provide insight into how you can repeat these successes and avoid the failures.
  • As an IT manager, this book explains how technology and business objectives influence the software modernization processes.

In particular, it should help you answer the following questions:

  1. When and how do I decide if a modernization or replacement effort is justified?
  2. How do I develop an understanding of the legacy system?
  3. How do I gain an understanding of, and evaluate the applicability of, information system technologies that can be used in the modernization of my system?
  4. When do I involve the stakeholders and how can I reconcile their conflicting needs?
  5. What role does architecture play in legacy system modernization?
  6. How can I estimate the cost of a legacy system modernization?
  7. How can I evaluate and select a modernization strategy?
  8. How can I develop a detailed modernization plan?
Organization and Content

Modernizing Legacy Systems: Software Technologies, Engineering Processes and Business Practices shows how legacy systems can be incrementally modernized. It uses and extends the methods and techniques described in Building Systems from Commercial Components Wallnau, 2001 to draw upon engineering expertise early in the conceptual phase to ensure realistic and comprehensive planning.

This book features an extensive case study involving a major modernization effort. The legacy system in this case study consists of nearly 2 million lines of COBOL code developed over 30 years. The system is being replaced with a modern system based on the Java 2 Enterprise Edition (J2EE) architecture. Additional challenges include a requirement to incrementally develop and deploy the system. We look at the strategy used to modernize the system; the use of Enterprise JavaBeans, message-oriented middleware, Java, and other J2EE technologies to produce the modern system; the supporting software engineering processes and techniques; and the resulting system.

Chapters 1 of this book provides an introduction to the challenges and practices of software evolution and Chapter 2 introduces the major case study in the book.

Chapter 3 introduces the Risk-Managed Modernization (RMM) approach which is elaborated in Chapters 4 through 17 and illustrated by the case study. Throughout Chapters 4 through 17 we provide an activity diagram of RMM as a road map to each chapter.

Chapter 18 provides some recommendations to help guide your modernization efforts (although these recommendations cannot be fully appreciated without reading the main body of the book).

Throughout this book we use the Unified Modelling Language (UML) to represent architecture drawings and design patterns. A brief introduction to UML is provided in Chapter 6.

0321118847P10182002

Index

Click below to download the Index file related to this title:
Index

Updates

Submit Errata

More Information

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020