Adjustment of sporadic server parameters in multimedia application

Since general purpose operating systems cannot satisfy all the demands of real-time applications, they have been extended. A Windows NT extension for the operation in application of moving picture transmission on a local network is presented. In contrast to commercial extensions, an application-and scheduling-based extension has been developed. It is targeted to the network and display card. The tool developed for the evaluation of scheduling algorithms has enabled an off-line selection of a combination of scheduling algorithms. RMS and sporadic server algorithms improve functioning of the described multimedia application. The increasing of aperiodic tasks schedulability can cause a decrease of periodic tasks schedulability. By adjusting the sporadic server parameter values we determine minimal server capacity and maximal server period in order to ensure necessary aperiodic tasks schedulability, whereby periodic tasks schedulability should be disturbed as little as possible. The described adjustment procedure enables a faster and safer determination of sporadic server parameters. Carefully selected parameters have enabled further improvement concerning moving picture transmission on a local network.