Why read this book?
Transaction processing has been an important software technology for 40 years. Large enterprises in transpor-
tation, finance, retail, telecommunications, manufacturing, government, and the military are utterly dependent
on transaction processing applications for electronic reservations, banking, stock exchanges, order processing,
music and video services, shipment tracking, government services, telephone switching, inventory control, and
command and control. Many large hardware and software vendors receive much of their revenue from compo-
nents of transaction processing systems, such as IBM, HP, Oracle, Microsoft, Dell, Red Hat, and EMC. The
market for transaction processing products and services is many tens of billions of dollars per year. As con-
sumers, we all use this technology every day to withdraw cash, buy gas, rent movies, and make purchases on
the Internet.
How exactly do these transaction processing systems work? This question was once of interest only to com-
puter professionals in the commercial data processing field. Now, given the widespread use of transaction pro-
cessing in today’s economy, it is of interest to a much broader engineering audience. Despite this interest, there is
little written for a system professional to get a readable, technically solid introduction to this complex technology.
This book fills the gap.
The software environment of most large-scale transaction processing systems is based on transactional mid-
dleware, which helps knit together many software components. These components include front-end applications
to drive web browsers and other devices, middle-tier applications to route requests to the server that can run
them, and server applications that execute business logic. Examples of transactional middleware include IBM’s
CICS; Microsoft’s .NET Enterprise Services; and Java Enterprise Edition products, such as IBM WebSphere
Application Server, Oracle’s WebLogic Server, and Red Hat’s JBoss Application Server. The first half of this
book focuses on transactional middleware technology.
For many software engineers, transactional middleware is obscure technology—strange software glue that
seems to be needed beyond operating systems, database systems, communication systems, and application pro-
gramming languages. This book demystifies transactional middleware by explaining how it contributes to the
performance, security, scalability, availability, manageability, and ease-of-use of transaction processing systems.
The first half of the book explains transactional middleware outside and in—the features it offers to application
programmers and how it is constructed to offer these features.
The transaction abstraction itself is largely implemented by database systems. They ensure that each trans-
action executes in its entirety, is isolated from interference by other transactions, and generates results that will
survive hardware and software failures. This behavior is implemented by locking, logging, communication
protocols, and replication. These technologies are the subject of the second half of this book.
This book is an introduction to transaction processing, intended to meet the needs of a broad audience,
including:
n Application programmers with an interest in building transaction processing applications
n Database administrators who manage database systems used for transaction processing
n Application analysts who design applications for deployment on transaction processing systems
n Product developers in related areas, such as database systems, operating systems, and communications
Preface
