In this paper we propose a virtualization layer to handle the program execution on reconfigurable computers in order to address one of their biggest problems which is the management of the reconfigurable hardware in a multitasking environment. The virtualization layer is responsible for allocating the hardware at run-time based on the status of the system. Furthermore, it provides a consistent and low overhead interface to decouple the process of software development from hardware design which will result in the software to be independent of the underlying reconfigurable hardware. This paper discusses the virtual layer's specification and components. Our preliminary results for a prototype simulated on Molen hardware organization show a competitive performance comparing with an optimal hardware allocation.

Multitasking reconfigurable computers with one or more reconfigurable processors are being used increasingly during the past few years. One of the major challenges in such systems is the scheduling and allocation of the tasks on the reconfigurable fabric. In this paper we present a two level scheduling mechanism for tightly coupled reconfigurable architecture machines. To overcome the complexity of identifying kernels at runtime, we use the compiler support. The compiler provides the runtime system with a configuration call graph which will be used as a viable source of information for the scheduling algorithm. We combine the configuration call graphs from all running applications and extract the distance to the next call and frequency of calls in future for each kernel from this graph. We base our scheduling decisions on these two parameters. Evaluation results show that the proposed method is very promising and it has the potential to be considered for future research.

In this paper we have carefully examined two variants of the Round Data Mailer protocol. It is shown that the version, which is designed to be implemented for the MAC layer, has better performance in comparison with the one which is implemented as multi layer protocol.

Many scheduling algorithms have been studied to guarantee the time constraints of real-time processes. Scheduling decision of these algorithms is usually based on parameters which are assumed to be crisp. However, in many circumstances the values of these parameters are vague. The vagueness of parameters suggests that we make use of fuzzy logic to decide in what order the requests should be executed to better utilize the system and as a result reduce the chance of a request being missed. We have proposed a new fuzzy algorithm called highest fuzzy priority first. The performance of this algorithm is compared with the well-known earliest deadline first algorithm through simulation. For both algorithms, tasks are considered to be non-preemptable. Simulation results show that this fuzzy approach outperforms the earliest deadline first has algorithm in that it decreases the number of missed deadlines and serves more important tasks better