This paper presents a simulator that uses graphical animation to convey the concepts of various scheduling algorithms for a single CPU. The simulator is unique in a number of respects. First, it uses a more realistic process model that can be configured easily by the user. Second, it graphically depicts each process in terms of what the process is currently doing against time. Using this representation, it becomes much easier to understand what is going on inside the system and why a different set of processes is a candidate for the allocation of the CPU at different time. A third unique feature of the simulator is that it allows the user to test and increase his understanding of the concepts studied by making his own scheduling decisions, through the very easy-to-use graphical user interface of the simulator. The simulator can be used by students in operating system courses or by anyone interested in learning CPU scheduling algorithms in an easier and a more effective way.

Abstract-Today, an organization's biggest asset is its data. Knowledge of relational databases and SQL (Structured Query Language) is one of the most valued technical skills and in high demand in most organizations. Students of any major can benefit in their careers from learning these fundamental database concepts. At our school, database classes for both CS (Computer Science) and non-CS students are offered by our computer science faculty members. Teaching database concepts can be challenging especially to non-CS students. In this paper, we discuss the technical difficulties our non-CS students experience in their database class and an approach to solving these problems.

Traditional operating systems control the execution of programs regardless of how often they are run. This raises the question: can't the often run or the often used programs provide better performance if an operating system had an ability to optimize their execution behavior based on a knowledge the operating system had obtained from their previous execution(s)? In this paper, we integrate this ability into a part of an operating system called a process scheduler and examine its cost and benefit. Our initial evaluations show that the cost involved in our scheduler is small and the processing time can be reduced by using this scheduler.

Traditional operating systems control the sharing of the processor resources among processes using a jixed scheduling policy based on the Utilization of a computer system such as real-time or timesharing systems. Since the control over the processor allocation is based on a fixed policy, not based on processes' execution behavior, this can hinder an effective use of a processor or can extend the processing time of a process unnecessarily. Thus, we proposed a couple of process scheduling policies which respond to processes' execution behavior. One of these policies is the policy f o r improving a Web server's response time. This policy controls multiple processes of a Web server by adjusting the execution of these processes according to their predicted behavior. And we evaluated the performance of a Web server using this policy in simple cases.In this paper, we evaluate the performance of a Web server when it is busy which is likely to be a realistic case. This could be the case in which it is most desirable to improve the response time of a Web server. Our experimental results show that the mean response times are improved greatly (up to 33.8% in the best case). They also show that the scheduling pornmeter is effectively predicted and updated by our mechanism based on the Web server's execution behavior.

CPU scheduling is one of the most important topics in operating systems courses. However, the main problem in learning CPU scheduling from textbooks is that textbooks usually simplify the illustration of CPU scheduling algorithms by using an unrealistic process execution model. They also do not give concrete examples when discussing complex algorithms. As a result, students are not able to gain insight into exactly how the algorithms work in real-world operating systems. To address this problem, the author developed an interactive Java-based software tool that uses graphical animation to convey the concepts of various CPU scheduling algorithms for a single CPU. While many existing animation tools were designed to be closely aligned with the content in traditional operating systems textbooks, this tool is uniquely designed and different in a number of respects. In this paper, the impact of the tool on student learning is measured , analyzed and discussed in detail. The tool has been used in two sections of the operating systems course at the author's institute, and has demonstrated effectiveness in assisting student learning of CPU scheduling algorithms.