Doctoral Thesis / Dissertation from the year 2017 in the subject Computer Science - Internet, New Technologies, grade: 1,3, PAF Karachi Institute of Economics and Technology, language: English, abstract: The work presented in this book focuses on the issue of task scheduling and resource allocation in desktop grid systems and presents concrete contributions. Desktop grid systems are one of the largest paradigms of distributed computing in the world. The idea is to use the idle and underutilized processing cycles and memory of the desktop machines to support large scale computation. The design issues in desktop grid systems are much more complex as compared to traditional grid environment because the hosts (desktop machines) participating in the computation do not work under one administrative control and can become unavailable at any point in time. The heterogeneity and volatility of computing resources, for example, diversity of memory, processors, and hardware architectures also play its role. To get fruitful results from such hostile environment, scheduling tasks to better hosts become one of the most important issues. The main contribution of this work is about minimizing the applications turnaround time on desktop grid systems that can only be achieved through knowledgeable task scheduling mechanism. A Group based Fault Tolerant Scheduling and Replication Mechanism (labeled as GFTSRM) is proposed that uses collective impact of CPU and RAM, task completion history and spot checking to populate available hosts in relevant groups to perform group based task scheduling. It is shown that grouping the hosts on the basis of computing strength and behavior is necessary for better performance. Relevant replication strategies are appended to each group in order to reduce the wastage of processing cycles. Simulations are performed by using GFTSRM, FCFS (First Come First Serve) and PRI-CR-Excl (host exclusion based on the fixed threshold of clock rate). GFTSRM is compa
