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In This Issue - April 1996 Volume 47 Issue 2

CURRENT ISSUE - April 1996 Volume 47 Issue 2 A standard, easy-to-use, intuitive user interface for computer systems has been a goal of system developers since the days of the ENIAC* computer. The UNIX) operating system, which began life as a system for engineers only, has been a consistent target for various user-interface schemes.

Before graphical user interfaces (GUIs) became commonplace, users interacted with computer systems via a character mode command-line interface. For UNIX systems, this command-line interface mode continued until the 1980s with the arrival of proprietary window systems. By 1988 the X Window System had been adopted as the standard window system for UNIX systems. Toolkits were created that allowed UNIX vendors to create as many different proprietary user interface environments as there were vendors. Article 1 introduces eight articles that describe how four UNIX vendors, who normally compete in the marketplace, collaborated on a user interface environment for UNIX platforms called the Common Desktop Environment, or CDE. This article explains how this environment is seen from three different viewpoints: developers who write applications to run in CDE, system administrators who must install and maintain these applications, and finally, end users who use these applications.

Since UNIX systems are highly networked, it is desirable that a desktop environment allow network transparency - the ability to launch applications and access data without worrying about where in the network these items are located. Thus, when the user selects an application (by double-clicking an icon) that happens to be on a remote system, the user environment automatically establishes links to the remote application server, allowing the user to run the application as if it were located on the local workstation. Article 2 describes the underlying mechanisms that link icons to applications, and the tools that enable system administrators to integrate applications into the desktop environment.

In most cases today the icons on a graphical desktop are fairly intuitive. For example, if you drop a document on a printer icon very likely the document will be sent to a printer of your choice. Article 3 describes the APIs (application programming interfaces) and databases responsible for defining the look and behavior of icons in the Common Desktop Environment.

The world of online help has evolved from simple out-of-context cryptic messages to media-rich, context-sensitive help messages. As Article 5 explains, the CDE help system is based on the easy-to-use HP VUE 3.0 help system. Like HP VUE 3.0, the CDE help system provides a language (HelpTag) for authors to develop help messages and tools for programmers to integrate customized help messages into their applications. The main difference between CDE help and HP VUE 3.0 help is the delivery format for help files. CDE help uses the semantic delivery language (SDL) as a delivery format for help files. SDL focuses on the semantics of a document.

Many users are content with the special menu and icon customizations they have in their current HP VUE interface. Therefore, to allow users to keep their menu and icon customizations in CDE, a collection of utilities are provided to translate HP VUE customizations into CDE equivalents. These utilities are described in Article 4 .

As mentioned above, the CDE project was a joint engineering effort between four companies that typically compete in the marketplace. The companies are HP, IBM, Sun Microsystems, and Novell. All four of these companies produce computer systems that use the UNIX operating system as their system platform. Because of different cultures and development strategies, the joint effort presented some interesting and unique challenges. In Article 6, the author describes the mechanisms and procedures that had to be put in place to manage the CDE project. Because of the different development strategies, test tools, and verification methods, the test team had the greatest challenge in this multicompany project. As Article 7 states, to ensure quality in the final product, strict guidelines were established at the beginning of the project. For example, rules were established for test coverage and assigning reponsibility when defects were found.

One of the tools that made testing the graphical user interface of CDE much easier is a test tool called Synlib. Typically, an image capture and compare technique is used to verifiy the various windows (screen states) of a GUI. However, this technique is sometimes prone to inaccuracies. Although the image capture technique was used for CDE testing, the majority of GUI testing used Synlib. Synlib reduces the need to use image capture for checking screen states because it employs a combination of position independent and position dependent data to manipulate and verify desktop items. Synlib is introduced in Article 7 and described in Article 8 .

For a mobile telephone to be competitive today it must supply full output power at a supply voltage of 5.4 volts (five NiCad cells ) with 40% efficiency and 0-dBm input power. It should also be inexpensive, small, have a long talk time, and be able to be manufactured in volume. These characteristics determine the specifications for the power module in a mobile telephone. The power module in a mobile telephone is the output stage of the RF (radio frequency) amplification chain of the telephone. Article 9 describes the design of a 3.5-watt power module for a GSM (Global System for Mobile Communications) mobile telephone, which satisfies all the specifications mentioned above.

Article 10 is a good example of the wide range of products offered by HP. The HP G1009A C-terminal protein sequencing system is a complete, automated system for the carboxy-terminal amino acid sequence analysis of protein samples. Using adsorptive sample loading and a patented sequencing chemistry, the HP G1009A is capable of detecting and sequencing through any of the 20 common amino acids.

Time-domain reflectometry (TDR) is commonly used for determining the characteristic impedance of a transmission line or quantifying reflections caused by discontinuities along or at the termination of a transmission line. However, as Article 11 explains, TDR can also be used to measure the capacitance or inductance of devices or structures while they reside in the circuit. The typical inductance-capacitance-resistance (LCR) meter cannot make these measurements accurately. The article shows how the HP 54750A oscilloscope and the HP 54754A TDR plug-in card can be used to make these measurements.

C.L. Leath
Managing Editor

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