Page 19 - Accounting Information Systems

xviii Preface

providing the organization with unquestioned benefit, a potential consequence of such
integration is a loss of control due to the blurring of the lines that traditionally separate
AIS from non-AIS functions. The conceptual framework presented in this book dis-
tinguishes AIS applications that are legally subject to specific internal control
standards.

EVOLUTIONARY APPROACH
Over the years, accounting information systems have been represented by a number of
different approaches or models. Each new model evolved because of the shortcomings
and limitations of its predecessor. An interesting feature in this evolution is that older
models are not immediately replaced by the newest technique. Thus, at any point in
time, various generations of legacy systems exist across different organizations and of-
ten coexist within a single enterprise. Modern accountants need to be familiar with the
operational characteristics of all AIS approaches that they are likely to encounter.
Therefore, this book presents the salient aspects of five models that relate to both
legacy and state-of-the-art systems:
1. manual processes
2. flat-file systems
3. the database approach
4. the resources, events, and agents (REA) model
5. enterprise resource planning (ERP) systems

EMPHASIS ON INTERNAL CONTROLS
The book presents a conceptual model for internal control based on Statement on
Auditing Standards no. 78 (SAS 78) and the Committee of Sponsoring Organizations
of the Treadway Commission (COSO) frameworks. This SAS 78/COSO model is used
to discuss control issues for both manual processes and computer-based information
systems (CBIS). Three chapters (Chapters 15, 16 and 17) are devoted to the control of
CBIS. Special emphasis is given to the following areas:
• computer operating systems
• database management systems
• electronic data interchange (EDI)
• electronic commerce systems
• ERP systems
• systems development and program change processes
• the organization of the computer function
• the security of data processing centers
• verifying computer application integrity

EXPOSURE TO SYSTEMS DESIGN AND
DOCUMENTATION TOOLS
This book examines various approaches and methodologies used in systems analysis
and design, including:
• structured design
• object-oriented design
• computer-aided software engineering (CASE)
• prototyping