Quality of Service (QoS) in terms of end-to-end delay guarantees to real-time applications is an important issue in emerging broadband packet networks. Earliest Deadline First (EDF) scheduling, in conjunction with per-hop traffic shaping (jointly called Rate Controlled EDF or RC-EDF) has been recognised as an effective means of end-to-end deterministic delay provisioning. This paper addresses t...

We address the issue of reserving resources at packet switches along the path of connections requiring a deterministic end-to-end delay bound. The switches are assumed to schedule outgoing packets using either the Packet-by-Packet Generalized Processor Sharing (PGPS) or the Rate-Controlled Earliest-Deadline First (RC-EDF) scheduling disciplines. We propose a set of resource reservation policies...

The purpose of this paper is to present the density of a task as a heuristic to schedule real-time tasks. The density of a task is defined as the ratio between the computation time of the task and the minimum of its relative deadline and period. We propose the Highest Task Density First (HTDF) algorithm to schedule tasks in real-time systems. HTDF is a dynamic priority scheduling algorithm that...

In uniform multiprocessor platforms, the various processors comprising the multiprocessor platform may have different computing capacities. The focus of this paper is the design of efficient tests for determining whether the Earliest Deadline First Scheduling Algorithm (EDF) can successfully schedule a given real-time task system to meet all deadlines upon a specified uniform multiprocessor pla...

Earliest Deadline First (EDF) and Fixed Priority (FP) scheduling represent the two main dispatching policies within the research domain of real-time systems engineering. Both dispatching policies are now supported by Ada. In this paper the two approaches are combined to maximize the advantages of both schemes. From EDF comes efficiency, from FP predictability. A system model is presented in whi...

All real time tasks which are termed as critical tasks by nature have to complete its execution before its deadline, even in presence of faults. The most popularly used real time task assignment algorithms are First Fit (FF), Best Fit (BF), Bin Packing (BP).The common task scheduling algorithms are Rate Monotonic (RM), Earliest Deadline First (EDF) etc.All the current approaches deal with eithe...

In this paper, we propose a reasonably simple and near-optimal soft aperiodic task scheduling algorithm in dynamic priority systems. The proposed algorithm has extended the EDF-CTI (Earliest Deadline First-Critical Task Indicating) Algorithm [4] in such a way of modifying the slack calculation method which in turns resolves the unit scheduling and the critical task misindicating problems. The p...

In a previous research project [5], we found there are several disadvantages of the current Linux scheduler. So we employed a alternative scheduler, Resource-Based Earliest Deadline First scheduler(RB-EDF), to solve these problems. Though RB-EDF performs better than the Linux scheduler in handling soft realtime processes, it can not enforce resource usages smaller than 1 tick(10ms) using the re...

It is well known that the Earliest-Deadline-First (EDF) and the Least-Laxity-First (LLF) algorithms are optimal algorithms for the problem of preemptively scheduling jobs that arrive over time on a single machine to minimize maximum lateness. It was not previously known what other online algorithms are optimal for this problem. A complete characterization of all optimal online algorithms for th...

A VOD server handles various types of media such as continuous media (CM) and non-continuous media (NM). Conventional VOD server buffer scheduling algorithms like Round Robin (RR) and Earliest Deadline First (EDF) have tradeoffs between guaranteeing the deadline of CM and getting a fast response time of NM. The former performs well in a NM environment while the latter is suitable for CM. In thi...