The phenomenal growth and complexity of computer networks has created a wealth of opportunities for communication and resource sharing and a multitude of concerns about privacy and security. The Open Software Foundation's Distributed Computing Environment (DCE) was developed to fill the need for a standardized approach to creating and executing secure client/server applications in complex, highly networked environments. Applications developed using the DCE software system are portable and interoperable over a wide range of computers and networks. Applications running in DCE are also able to share data and services efficiently and securely regardless of the number of computers used or where they are located. HP, like some other companies in the computer industry, has contributed technologies to DCE and released several versions of DCE as a product for the HP-UX* operating system. The first eight articles in this issue describe the fundamental elements of DCE and the enhancements made to DCE by HP in the areas of application development and security.

DCE is based on the client/server model in which an application's functionality is divided between clients, which represent users, and servers, which provide the services requested by users. In a DCE environment, there might be several thousand host systems, some of which might be from different vendors, and many different categories of users and applications. To deal with this heterogeneous and diverse environment, DCE defines a basic unit of operation and administration called a cell, which allows users, systems, and resources to be grouped together according to their needs and common interests. The client/server paradigm and the concept of cells are introduced in the article on page 6 . This article also introduces features in DCE that facilitate concurrent programming, DCE client/server remote communication, time synchronization between distributed hosts, and handling a distributed file system.

Encouraging others to adopt a new technology is made a lot easier if you have examples of its use. HP's information technology group has adopted DCE and has begun to move HP's legacy information technology system to the DCE architecture. The article on page 16 describes the issues and rationale that led HP to adopt DCE for information technology, and the administration and planning issues associated with this transition.

A typical DCE cell can span several systems and networks. To find users, files, devices, and resources inside and outside these cells requires a naming system that allows each cell and the objects contained inside it to have unique names, and a directory service that can cope with different naming systems. The article on page 23 describes the DCE directory services and the article on page 28 describes the X/Open) Federated Naming specification, which defines a uniform naming interface for accessing a variety of naming systems.

One of the biggest issues surrounding networked systems today is security. How do we protect an open, distributed system from unauthorized access and abuse? DCE provides a collection of services for developing security mechanisms to protect against unauthorized access. The user's password is the primary key for getting into a system, and in some situations users may be required to enter several passwords during a session to gain access to different applications or other parts of the system. Each time the user is required to enter another password, the system is made vulnerable to an opportunity for hostile invasion. The article on page 34 describes the HP Integrated Login product, which is a single-step login facility in which the user enters a password once at login time, and this password is used to grant access to the HP-UX machine as well to verify access to other secured parts of the system. The security protocol that takes over after the password is entered is described in the DCE security service article on page 41. The DCE security service authenticates a legitimate user and then checks to make sure that the user is authorized to have access to the requested services. The article on page 49 describes one of these authorization mechanisms called access control lists (ACLs). ACLs are lists of permissions that belong to certain users or groups of users.

DCE provides several very powerful facilities for creating DCE client/server applications. However, the interfaces to some of these facilities are quite complex. The article on page 55 describes the HP Object-Oriented DCE (OODCE) product, which is an object-oriented library of C++ classes that hide the programmatic complexity of DCE from developers to ease the development of distributed applications.

Transaction processing systems are used in large enterprises to store, retrieve, and manipulate data reliably in the face of concurrent access. The HP Encina/9000 transaction processing monitor described on page 61 provides an environment for developing distributed OLTP (online transaction processing) applications. Encina/9000 uses many of the features of DCE to create its distributed, client/server capabilities.

One of the biggest challenges in software development is still testing the product. This challenge is even more daunting in distributed client/server environments. In the article on page 75 the authors describe how the testing environment for nondistributed, procedural software is not applicable to a distributed environment. The article describes the evolution of a reusable, object-oriented testing environment called the object testing framework (OTF). Although OTF was designed for a non-DCE-based product, the concepts and tools developed for OTF are applicable to products that might be based on DCE.

Bar code readers and magnetic strips are so commonplace today that their usefulness in areas such as banking, manufacturing, and retail is taken for granted. However, these technologies do have their limitations in that they require a direct line of sight and a relatively clean, benign environment. Another technology called RF/ID (radio frequency identification), which is a combination of two components-a transmitter and a receiver-overcomes the limitations of these other technologies. The article on page 94 describes the HP HSMS-285x silicon detector diodes designed for use in RF/ID applications.

In today's modern hospitals patients who have to be monitored are connected to an array of high-tech patient monitoring equipment. Aware of the intimidating look of all this equipment, many hospitals are trying to create a more friendly environment in their labor and delivery departments by reducing the amount of technology at the patient's bedside. The HP Series 50 T fetal telemetry system, which is described in the article on page 82 is a step in this direction. The HP Series 50 T combines external and internal fetal monitoring in a lightweight, portable transmitter.

C.L. Leath
Managing Editor