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A security kernel is a software and hardware mechanism that enforces access controls within a computer system. The correctness of a security kernel on a PDP-11/45 is being proved. This paper describes the technique used to carry out the first step of the proof: validating a formal specification of the program with respect to axioms for a secure system. [ABSTRACT FROM AUTHOR]

This paper investigates mechanisms that guarantee secure information flow in a computer system. These mechanisms are examined within a mathematical framework suitable for formulating the requirements of secure information flow among security classes. The central component of the model is a lattice structure derived from the security classes and justified by the semantics of information flow. The lattice properties permit concise formulations of the security requirements of different existing systems and facilitate the construction of mechanisms that enforce security. The model provides a unifying view of all systems that restrict information flow, enables a classification of them according to security objectives, and suggests some new approaches. It also leads to the construction of automatic program certification mechanisms for verifying the secure flow of information through a program. [ABSTRACT FROM AUTHOR]

This article discusses developments in the field of computer application. The personal computer industry has designed computer power into smaller, mobile, consumer products. Sharp, Casio, and Nintendo have built major businesses around personal electronic organizers and hand-held games. A new set of players has just entered the race with new ideas about small computers. New devices promise to reach beyond calendars, telephone books and games. Soon personal digital assistants will provide consumers with a form of "smart paper." Not only will these devices recognize handwritten characters, but also it will interpret and perform the operations symbolized by handwritten mathematical formulas. Such small general purpose devices will deliver computer power to new situations anytime, anywhere. To support an extension from desktop to ubiquitous computing, pens and associated writing recognition software will allow non computer users to access computing power in situations that do not accommodate keyboards.

This article introduces papers discussed in the August 1991 issue of the periodical "Communications of the ACM." The ability to communicate across disciplinary borders has become both a skill and a necessity for many computer professionals in the 1990s. The idea for August 1991 special section, "Real-Time Knowledge-Based Control Systems" originated in an AAAI workshop motivated by the recognition that constructing robotic systems capable of autonomous, flexible, intelligent behavior is an inherently interdisciplinary activity. As part of their technical discussions, the authors detail how this technology can be applied to such diverse areas as nuclear power plants, robotic vehicles, and chemical processing. In addition to the special section, August issue includes two computing practices articles. In "Impacts of Life Cycle Models on Software Configuration Management," authors survey the current state of the practice of software configuration management. The authors contend that some evolving software engineering practices will soon replace the waterfall model as the de facto standard in the field. In "A Storage and Access Manager for Ill-Structured Data," authors discuss the James system, which was designed to provide flexible storage and access for a wide variety of ill-structured data such as text, graphics, computer models, semantic networks, and production rules.

The article reports on how content-addressed storage (CAS) systems can help information technology managers bring their organizations into compliance with regulatory mandates. CAS is an intelligent repository used to store and preserve compliance-sensitive documents such as medical records, blueprints, invoices and e-mail messages. Each piece of data that is fed into CAS are being stored using identifiers, which ensures that sensitive business content is not altered and that the paper trail is preserved within the context of a paperless environment. It also has the ability to perform high-speed searches through the repository.

This article focuses on the use of tablet PCs (personal computers) in higher education. Slow to catch on, tablet PCs have yet to break annual global sales of 500,000; by comparison, 189 million PCs sold in 2004, according to Gartner Research. Many people are impressed by the tablet PC's ability to function like a pen and paper, but they've been less impressed with what tablet PCs have lacked: keyboard, onboard disk drive and affordable price points. This could change in 2005 as computer makers like Gateway, HP, and Toshiba are launching next generation tablets with keyboard and disk drives onboard.

The article highlights the 31st annual conference of the Special Interest Group on Graphics (SIGGRAPH) of the Association for Computing Machinery held at the Los Angeles Convention Center in Los Angeles, California from August 8 to 12, 2004. A couple of decades ago, conference attendees could count on seeing a couple things at SIGGRAPH that had literally never been seen before in human history, such as textured 3D objects or hierarchical human animation. SIGGRAPH 2004's total exhibition area was smaller than the hallowed days of yore, composed mostly of software companies, some boutique specialty hardware outfits, schools, and graphics board manufacturers. Walking the show's exhibit floor provides ample evidence that the industry's major players have changed in recent years. One reason the show floor's smaller is that there's been considerable consolidation in both the hardware and software graphics industries over the last few years. There were several indications this trend is still in full swing. One class of hardware that wasn't in evidence at the show was tablet computers. There's exactly one attendee using a tablet, compared to hundreds of laptops of every size and description. If the SIGGRAPH community's resisted adopting tablets as mobile work devices, one wonders if there's any hope for them in the wider community, at least until they become as thin and light as paper.

This article reports on the 31st annual conference of the Special Interest group on Graphics (SIGGRAPH) of the Association for Computing Machinery held at the Los Angeles Convention Center from August 8-12, 2004. The show drew 27,825 attendees, down from its high of nearly 50,000 seven years ago, but up from 17,000 two years ago. SIGGRAPH remains the Mother of All Imaging Conferences, featuring a unique mix of science, art, commerce, and education. With a wide selection of panels, papers, films, and innovative exhibits, SIGGRAPH rarely disappoints. SIGGRAPH 2004's total exhibition area was smaller than the hallowed days of yore, composed mostly of software companies, some boutique specialty hardware outfits, schools, and graphics board manufacturers. Walking the show's exhibit floor provides ample evidence that the industry's major players have changed in recent years. Where once SGI's purple, blue, and fuchsia workstations were literally ubiquitous on a vast show floor, this year they occupied only a small booth. Graphics card makers NVIDIA and ATI have replaced SGI as the 800 pound gorillas of the industry. One reason the show floor's smaller is that there has been considerable consolidation in both the hardware and software graphics industries over the last few years. There were several indications this trend is still in full swing.

This article discusses the innovative applications created over the years by great designers. One example is Agenda from Lotus. This personal information manager offered a dazzling array of flexible features and views. Lotus also created Improv, a next-generation spreadsheet. Introduced as a showcase piece of software for NeXT platform, it was as different from anything that had come before it as spreadsheets were from paper ledgers. The author then relates how today's programs are either too simplistic in functionality or too arcane for people. He relates his boredom for the complex hardware and software and emphasizes the need for innovation.

The article reports that Bea Systems Inc. has launched the AquaLogic Interaction Process computer software in the U.S. The updated tool allows multiple people to use and manage documents and project information through portals. Red Bank vice president of software development Andrew Reid plans to use the updated Bea tool to automate the paper-based-processes for granting user access to restricted applications and data. The new tool will create the company electronic records. It also allows business analysts to model and design a business process and to designate the roles for participants.