Previous work in real-time database management systems (RT-DBMS) has primarily focused on simulation. This paper discusses how current real-time technology has been applied to architect an actual RTDBMS on a real-time microkernel operating system. A real RT-DBMS must confront many practical issues which simulations typically ignore: race conditions, concurrency, and asynchrony. The challenge of...

This thesis is concerned with the computation of buffer capacities that guarantee satisfaction of timing and resource constraints for task graphs with aperiodic task execution rates that are executed on run-time scheduled resources. Stream processing applications such as digital radio baseband processing and audio or video decoders are often firm real-time embedded systems. For a real-time embe...

ÐIn a hard real-time system, it is assumed that no deadline is missed, whereas, in a soft or firm real-time system, deadlines can be missed, although this usually happens in a nonpredictable way. However, most hard real-time systems could miss some deadlines provided that it happens in a known and predictable way. Also, adding predictability on the pattern of missed deadlines for soft and firm ...

Time-utility functions (TUFs) as means for scheduling allow to build flexible real-time systems. TUFs yield utility values for single job executions. We extend this concept to history-cognisant utility functions (HCUFs) that assign an overall utility value to a whole task. We aim to use such HCUFs to improve the single-task performance in control systems. We present two extensions of the EDF po...

than traditional real-time scheduling in the sense that certain aspects of transactions may not integrate well with real-time scheduling. This paper introduces a dynamic admission control and parametrable priority based scheduling algorithm called H/M/L. It is based on the transaction importance, an attribute given by the programmer. We consider a multi-class transaction workload consisting of ...

In conventional database systems, performance is primarily measured by the number of transactions completed within a unit time. In real-time applications, timing and criticality characteristics of transactions must be taken into account. In this paper, we examine the performance of StarBase, a firm real-time database system. The deadline guarantee ratio and average response times are the primar...