Today’s business enterprises must deal with global competition, reduce the cost of doing business, and rapidly develop new services and products. To address these requirements enterprises must constantly reconsider and optimize the way they do business and change their information systems and applications to support evolving business processes. Workflow technology facilitates these by providing methodologies and software to support (i) business process modeling to capture business processes as workflow specifications, (ii) business process reengineering to optimize specified processes, and (iii) workflow automation to generate workflow implementations from workflow specifications. This paper provides a high-level overview of the current workflow management methodologies and software products. In addition, we discuss the infrastructure technologies that can address the limitations of current commercial workflow technology and extend the scope and mission of workflow management systems to support increased workflow automation in complex real-world environments involving heterogeneous, autonomous, and distributed information systems. In particular, we discuss how distributed object management and customized transaction management can support further advances in the commercial state of the art in this area.

The basic transaction model has evolved over time to incorporate more complex transaction structures and to selectively modify the atomicity and isolation properties. In this chapter we discuss the application of transaction concepts to activities that involve coordinated execution of multiple tasks (possibly of different types) over different processing entities. Such applications are referred to as transactional workflows. In this chapter we discuss the specification of such workflows and the issues involved in their execution. 1 What is a Workflow? Workflows are activities involving the coordinated execution of multiple tasks performed by different processing entities. A task defines some work to be done and can be specified in a number of ways, including a textual description in a file or an email, a form, a message, or a computer program. A processing entity that performs the tasks may be a person or a software system (e.g., a mailer, an application program, a database mana...

A Transaction Specification and Management Environment (TSME) is a programmable system that supports: (i) implementation-independent specification of application-specific extended transaction models (ETMs), and (ii) configuration of transaction management mechanisms (TMMs) to enforce specified ETMs. The TSME can ensure correctness and reliability while allowing the functionality required by workflows and other advanced applications that require access to multiple heterogeneous, autonomous, and/or distributed (HAD) systems. To support ETM specification, the TSME provides a transaction specification language that describes dependencies between transactions. Unlike other transaction specification languages, TSME's dependency descriptors use a common set of primitives, and are enforceable, i.e., can be evaluated at any time during transaction execution to determine whether operations issued violate ETM specifications. To determine whether an ETM can be enforced in a specific HAD system env...

A variety of extensions to the traditional (ACID) transaction model have resulted in a plethora of extended transaction models (ETMs). Many of these ETMs are application-specific, i.e., they are designed to provide correctness guarantees adequate for a particular application, but not others. Similarly, an application-specific ETM may impose restrictions that are unacceptable in one application, yet required in another. To define new ETMs, to determine whether an ETM is appropriate for an application, and to integrate ETMs to produce new ETMs, we need a framework for ETM specification and reasoning. In this paper, we describe such a framework. Our framework supports implementation-independent specification of ETMs described in terms of dependencies between transactions. Dependencies are specified using dependency descriptors. Unlike other transaction specification frameworks, dependency descriptors use a common set of primitives, and are enforceable, i.e., can be evaluated at...

Introduction Distributed object computing is evolving as a new paradigm for solving complex distributed systems problems. It is supported by Distributed Object Management Systems (DOMSs) [MHGH+92], which are object-oriented environments in which distributed, autonomous, and heterogeneous systems (such as database and legacy systems) can be integrated, and complex, non-traditional applications can be developed. A DOMS integrates local systems by representing their data and functionality as objects, and allowing client applications to access them without knowing their location, access language, or data representation. It must ensure correct and reliable execution across multiple objects. The scope of a DOMS ranges from small centralized systems to massive world-wide information systems. There is increasing interest in specifying applications in a DOMS environment as workflows involving distributed objects. A workflow is a collection of tasks organized to accompli