The modern personal computer is capable of executing many millions of instructions per second. Some of these instructions may cause the computer to slow down, expose security vulnerabilities to the outside world, or cause other undesirable behavior. It is impractical and unwieldy to regularly probe the operating system’s kernel and analyze enormous text files for detecting anomalous behavior. Y...

The rapid growth of networking, data sharing, and the Internet has made computer security an important part of computer research and development. A number of highly secure operating systems have been developed to handle the increasing need for security. These operating systems, typically called Trusted Operating Systems, offer a number of security mechanisms that can help protect information, m...

Public and private organizations maintain large systems of files to be accessed by many users. Clearly, access to information in these files must be regulated so that specific items are made available to specific users, in accordance with rules and limitations deemed appropriate by management. The totality of these rules and limitations constitute the (information) security policy of the organi...

A process is an instance of a computer program that is being sequentially executed by a computer system that has the ability to run several computer programs concurrently. A computer program itself is just a passive collection of instructions, while a process is the actual execution of those instructions. Several processes may be associated with the same program; for example, opening up several...

In this paper, we aren’t talking about primitive operating systems. We will discuss what is required of the computer hardware for a robust multiprogramming operating system. Let’s examine that description for a minute. A multiprogramming operating system is one that can run two or more programs at the same time, possibly for two or more users. A robust operating system is one where each user ap...

Competencies related to operating systems and computer security are usually taught systematically. In this paper we present a different approach, in which students have to remove virus-like behaviour on their respective computers, which has been induced by software developed for this purpose. They have to develop appropriate problem-solving strategies and thereby explore essential elements of t...

Local networks often consist of a cable snaking through a building with sockets in each room into which users can plug their personal computers. Using such a network for building a coherent distributed or network operating system is difficult because the system administrators have no control over the users' machines-not the applications programs, not the system kernel, not even the choice of ha...

Vol. 10 No. 1 1998 The computer architecture research community commonly uses trace-driven simulation in pursuing answers to a variety of design issues. Architects spend a significant amount of time studying the characteristics of benchmark programs by examining traces, i.e., samples taken from program execution. Popular benchmark programs include the SPEC and the BYTEmark benchmark test suites...

Trace-driven simulation is commonly used by the computer architecture research community to pursue answers to a wide variety of architectural design issues. Traces taken from benchmark execution have been extensively studied to optimize the design of pipelines, branch predictors, and especially cache memories. Today's computer designs have been optimized based on the characteristics of these be...

The XtreemOS operating system provides for Grids what a traditional operating system offers for a single computer: abstraction from the hardware and secure resource sharing between different users. It thus simplifies the work of users belonging to virtual organizations by giving them the illusion of using a traditional computer while removing the burden of complex resource management issues of ...