April 1999 - Vol. 42 No. 4

April 1999 issue cover image

Features

Opinion

Editorial Pointers

This month, we look at the evolutions unfolding in the worlds of hardware and software, both surely representing milestones in their respective spheres. We begin with a discussion of the value of free software, a controversial topic that has recently achieved new dimensions and spawned powerful and influential alliances—and foes. Our focus is the open-source […]
News

News Track

The speed of light, which travels through empty space at about 186,171 miles per second—the highest speed anything can attain—has been slowed to 38 miles an hour by Danish physicists, reports Nature. The medium used in slowing light by a factor of 20 million was a cluster of atoms called a “Bose-Einstein condensate” chilled to […]
Opinion

Forum

In the January 1999 Communications (p. 27), ACM President Barbara Simons says we should insist that leaders "spend less time worrying about how to censor the Net and more time on how to use it to provide timely and easy-to-access information about the workings of government." I’m not convinced that these two efforts are in […]
News

ACM Digital Library Enhancements

As the new Executive Director and CEO of ACM, I am delighted to have this opportunity to share with you my excitement regarding some of the new initiatives and services ACM is launching this year. The organization has made major investments and taken significant strides in the area of electronic publishing and services—the ACM Digital Library is the cornerstone of this initiative.
Research and Advances

Lessons from Open-Source Software Development

Open source is a term that has recently gained currency as a way to describe the tradition of open standards, shared source code, and collaborative development behind software such as the Linux and FreeBSD operating systems, the Apache Web server, the Perl, Tcl, and Python languages, and much of the Internet infrastructure, including Bind (the Berkeley Internet Name Daemon servers that run the Domain Name System), the Sendmail mail server, and many other programs. The Open Source campaign became international news in 1998 when Netscape decided to make the next version of its Web browser (Mozilla) an open-source product, and when IBM adopted the Apache Web server as the core of its WebSphere product line.
Research and Advances

The Linux Edge

Linux today has millions of users, thousands of developers, and a growing market. It is used in embedded systems; it is used to control robotic devices; it has flown on the space shuttle. I'd like to say that I knew this would happen, that it's all part of the plan for world domination. But honestly this has all taken me a bit by surprise—I was much more aware of the transition from one Linux user to one hundred Linux users than the transition from one hundred to one million users.
Research and Advances

The Origin of the Camel Lot in the Breakdown of the Bilingual -Unix

Approximately 12 years ago, the Unix programming universe consisted of two linguistic cultures. You either programmed in C, or you programmed in the shell (for some value of shell). The two systems were good for different things, so their capabilities were widely viewed as complementary. The revelation that came to me one day was simply that these capabilities were not, in fact, opposite ends of a single dimension, but rather the axes of a two-dimensional graph.
Research and Advances

Shared Leadership in the Apache Project

The Apache Project [1] is a collaborative software development effort aimed at creating and maintaining a robust, secure, efficient, extensible, and open-source implementation of an HTTP (Web) server. The project is managed by the Apache Group, a geographically distributed set of volunteers who use the Internet and Web to communicate, develop, and distribute the server and its related documentation. In addition, hundreds of users have contributed ideas, code, and documentation to the project. According to the Netcraft survey of November 1998 [4], the Apache server and its derivatives are used by over 57% of publicly accessible Web sites, more than double its nearest competitor.
Research and Advances

Free Software Needs Profit

Sooner or later, every successful open-source software package will have one or more profitable businesses associated with it. For example, the Linux operating system is supported by several companies including Red Hat and Caldera; the GNU tools are supported by Cygnus; the Sendmail email delivery system is supported by Sendmail, Inc.; and the Tcl scripting language is supported by my company, Scriptics. This association between open-source software and business is not just a historical artifact, but a necessity. On its own, open-source software lacks essential ingredients for mainstream adoption. Commercial businesses tied to open-source packages provide these ingredients and help drive open-source packages into the mainstream. At the same time, they provide additional resources for developing the free components of the software.
Research and Advances

Following the Path of Evolvable Hardware

Evolvable hardware (EHW) refers to one particular type of hardware whose architecture, structure, and functions change dynamically and autonomously in order to improve its performance in performing certain tasks [1]. The emergence of this new field has been influenced profoundly by the progress in reconfigurable hardware and evolutionary computation. Traditional hardware is notorious for its inflexibility. It is impossible to change the hardware's structure and functions once it is made. However, most real-world problems are not fixed. They change with time. In order to deal with these problems efficiently and effectively, different hardware structures are necessary. EHW provides an ideal approach—making hardware "soft" by adapting the hardware structure to a problem dynamically.
Research and Advances

Field-Programmable Gate Arrays

Field-programmable gate arrays (FPGAs) are integrated circuits, which constitute the “new kid in town” where digital hardware technology is concerned. An FPGA is an array of logic blocks (cells) placed in an infrastructure of interconnections, which can be programmed at three distinct levels (see Figure 1): (1) the function of the logic cells, (2) the […]
Research and Advances

Experiments on Evolving Software Models of Analog Circuits

Analog circuits are of great importance in electronic system design since the world is fundamentally analog in nature. While the amount of digital design activity far outpaces that of analog design, most digital systems require analog modules for interfacing with the external world. It was recently estimated that approximately 60% of digital application-specific integrated circuit […]
Research and Advances

OO Distributed Programming Is Not Distributed OO Programming

Object-oriented distributed programming is fundamentally different from building mechanisms that hide remote invocations behind traditional, centralized abstractions. The metaphor of a community of independent objects communicating by passing messages is misleading and dangerous when thinking in terms of a distributed system. That metaphor should not hide the significant difference between distributed interaction and local interaction. […]
Opinion

Inside Risks: Just a Matter of Bandwidth

The previously incomprehensible increases in communication capacities now appearing almost daily may be enabling a quantum leap in one of the ultimately most promising, yet underfunded, areas of scientific research—teleportation. But to an extent even greater than with many other facets of technology, funding shortfalls in this area can carry with them serious risks to […]

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