scholarly journals Virtual-CPU Scheduling in the Quest Operating System

Author(s):  
Matthew Danish ◽  
Ye Li ◽  
Richard West
2021 ◽  
Vol 1 (2) ◽  
pp. 1-16
Author(s):  
Mohammed Y. Shakor ◽  

An operating system is software that is designed to manage computer hardware and software resources. However, this management requires applying an ample number of techniques and algorithms which are called synchronization and scheduling. The scheduling algorithms are used to arrange the way that the CPU is assigned to the processes, while synchronization is utilized to indicate how to work with multi-processes at the same time. Therefore, they are related to each other. CPU scheduling is a vital phenomenon of an operating system. At present, numerous CPU scheduling algorithms exist as First Come First Serve) FCFS(, Shortest Job First (SJF), Shortest Remaining Time First (SRTF), Priority Scheduling, and Round Robin (RR). In this paper, a survey of the current synchronization and scheduling algorithms have been presented. An overview of each technique with the main algorithms have been described in detail with the advantages and the issues of each algorithm. Furthermore, this paper has dug deep into the real-time operating system scheduling issues, which is the current trend in operating system researches.


Author(s):  
Sonia Zouaoui ◽  
Lotfi Boussaid ◽  
Abdellatif Mtibaa

<p>This paper introduce a new approach for scheduling algorithms which aim to improve real time operating system CPU performance. This new approach of CPU Scheduling algorithm is based on the combination of round-robin (RR) and Priority based (PB) scheduling algorithms. This solution maintains the advantage of simple round robin scheduling algorithm, which is reducing starvation and integrates the advantage of priority scheduling. The proposed algorithm implements the concept of time quantum and assigning as well priority index to the processes. Existing round robin CPU scheduling algorithm cannot be dedicated to real time operating system due to their large waiting time, large response time, large turnaround time and less throughput. This new algorithm improves all the drawbacks of round robin CPU scheduling algorithm. In addition, this paper presents analysis comparing proposed algorithm with existing round robin scheduling algorithm focusing on average waiting time and average turnaround time.</p>


2020 ◽  
Vol 1 (2) ◽  
pp. 48-55
Author(s):  
Naji Harki ◽  
Abdulraheem Ahmed ◽  
Lailan Haji

The operating system (OS) is now being widely used in many of the various modern applications in recent years, ranging from diabetic monitoring to other strategic planning. The main function of any OS is to control and coordinate all hardware resources among the commands of the same/different user, which increases the efficiency of advanced comprehensive applications. In an autonomous computer system, the CPU is one of the important resources to manage and process all activities which require scheduling techniques on a processor. Since the early days of computing and other multi-programming OS, various studies have been assigned to CPU scheduling techniques based on processes management and performance evaluation. Thus, outlining the many issues related to scheduling methodologies and the weaknesses that need to be addressed. This review paper is organized based on two distinct perspectives: the implement strategies of CPU scheduling technique and criteria-based measures used, which assess how the strategies are analyzed and used under performance evaluation.


2019 ◽  
Vol 17 (1) ◽  
pp. 90-98 ◽  
Author(s):  
Uferah Shafi ◽  
Munam Shah ◽  
Abdul Wahid ◽  
Kamran Abbasi ◽  
Qaisar Javaid ◽  
...  

Central Processing Unit (CPU) is the most significant resource and its scheduling is one of the main functions of an operating system. In timeshared systems, Round Robin (RR) is most widely used scheduling algorithm. The efficiency of RR algorithm is influenced by the quantum time, if quantum is small, there will be overheads of more context switches and if quantum time is large, then given algorithm will perform as First Come First Served (FCFS) in which there is more risk of starvation. In this paper, a new CPU scheduling algorithm is proposed named as Amended Dynamic Round Robin (ADRR) based on CPU burst time. The primary goal of ADRR is to improve the conventional RR scheduling algorithm using the active quantum time notion. Quantum time is cyclically adjusted based on CPU burst time. We evaluate and compare the performance of our proposed ADRR algorithm based on certain parameters such as, waiting time, turnaround time etc. and compare the performance of our proposed algorithm. Our numerical analysis and simulation results in MATLAB reveals that ADRR outperforms other well-known algorithms such as conventional Round Robin, Improved Round Robin (IRR), Optimum Multilevel Dynamic Round Robin (OMDRR) and Priority Based Round Robin (PRR)


2014 ◽  
Vol 7 (1) ◽  
pp. 16-29
Author(s):  
Taqwa Flayyih Hasan

Scheduling is a key concept in computer multitasking and multiprocessing operating system design, and in real-time operating system design. CPU scheduling is the basis of multiprogramming operating systems by switching the CPU among process; the operating system can make the computer more productive, scheduling algorithms are widely used in communications networks and in operating systems to allocate resources to competing tasks. In this paper, visual interfaces for CPU scheduling algorithms were designed by using Visual Basic6 language. They may use to learn users about this algorithms and how they work


2018 ◽  
Vol 7 (4.5) ◽  
pp. 238 ◽  
Author(s):  
Govind Prasad Arya ◽  
Kumar Nilay ◽  
Devendra Prasad

The most important and integral part of a computer system is its operating system. Scheduling various resources is one of the most critical tasks an operating system needs to perform. Process scheduling being one of those tasks, involves various techniques that define how more than one processes can be executed simultaneously. The primary aim here is to the system more efficient and faster. The fundamental scheduling algorithms are: First Come First Serve (FCFS), Round Robin, Priority Based Scheduling, and Shortest Job First (SJF). This paper focuses on Round Robin Scheduling algorithm and various issues related to it. One major issue in RR scheduling is determining the length of Time Quantum. If the Time Quantum is too large RR scheduling behaves as FCFS. On the other hand, if it is too small it forces considerable increase in the number of context switches. Our main objective is to overcome this limitation of traditional RR scheduling algorithm and maximize CPU utilization, further, leading to more efficient and faster system. Here we propose an algorithm that categorizes available processes into High Priority processes and Low Priority process. The proposed algorithm reduces the average waiting time of High Priority processes in all cases and of Low Priority processes in not all but some cases. The overall waiting time changes on the basis of set of processes considered. The simulation results justify that the proposed schemes reduces the overall average waiting time when compared to the existing schemes. 


1996 ◽  
Vol 05 (03) ◽  
pp. 323-345
Author(s):  
DU ZHANG ◽  
RAUL VELEZ

This paper presents the design and implementation of a knowledge-based tool for performance tuning of the UNIX operating system. The tool, called BMS, provides an intelligent support and maintenance for identifying performance bottlenecks in UNIX and recommending solutions to the problems. Currently, it handles problems in UNIX resource management, such as memory utilization, disk utilization, CPU scheduling and I/O devices. BMS has been implemented in the EXSYS environment and tested on UNIX V.3. Preliminary results have indicated that such a knowledge-based tool to operating system performance tuning (1) is viable; (2) increases the productivity of system maintenance personnel and reduces the cost of training; and (3) offers a better service to operating system users by providing prompt recommendations to solutions of their system performance problems.


2020 ◽  
Vol 10 (15) ◽  
pp. 5134
Author(s):  
Samih M. Mostafa ◽  
Hirofumi Amano

Minimizing time cost in time-shared operating system is the main aim of the researchers interested in CPU scheduling. CPU scheduling is the basic job within any operating system. Scheduling criteria (e.g., waiting time, turnaround time and number of context switches (NCS)) are used to compare CPU scheduling algorithms. Round robin (RR) is the most common preemptive scheduling policy used in time-shared operating systems. In this paper, a modified version of the RR algorithm is introduced to combine the advantageous of favor short process and low scheduling overhead of RR for the sake of minimizing average waiting time, turnaround time and NCS. The proposed work starts by clustering the processes into clusters where each cluster contains processes that are similar in attributes (e.g., CPU service period, weights and number of allocations to CPU). Every process in a cluster is assigned the same time slice depending on the weight of its cluster and its CPU service period. The authors performed comparative study of the proposed approach and popular scheduling algorithms on nine groups of processes vary in their attributes. The evaluation was measured in terms of waiting time, turnaround time, and NCS. The experiments showed that the proposed approach gives better results.


After studying various CPU scheduling algorithms in Operating System, Round Robin scheduling algorithm is found to be most optimal algorithm in timeshared systems because of the static time quantum that is designated for every process. The efficacy of Round Robin algorithm entirely depends on the static time quantum that is being selected. After studying and analyzing Round Robin algorithm, I have proposed a new modified Round Robin algorithm that is based on shortest remaining burst time which has resulted in dynamic time quantum in place of static time quantum. This improves the performance of existing algorithm by reducing average waiting time and turn-around time and minimizing the number of context switches.


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