DEVS OS (Discrete Even Visualization and Simulation Operating System)

Author(s):  
Adnan Hajar

The use of traditional approaches to teach Operating Systems usually lacks the visual aspect. The following research investigates the novel use of DEVS (Discrete Even Visualization and Simulation) in simulating the operation of an operating system. Cd boost++ was the framework of choice for this project. The simulation successfully mimicked the work of an operating system by simulating multiple cycles of program requests. This simulation is capable of further enhance the explanation of how an operating system works. The cases studied in this work include: 1- two processes running concurrently doing multiple IO’s, 2-four processes running concurrently based on a first come first serve scheduling algorithm, and 3- 20 processes running concurrently using highest priority scheduling algorithm. Output observation of the last case show promising results of successful use of DEVS and cd boost++ as a framework to build an operating system.

2021 ◽  
Vol 336 ◽  
pp. 05031
Author(s):  
Xiaochun Wang

Huawei LiteOS is a real-time operating system. Thread schedulability is an important thing to be considered first when we use the RTOS in an application. There are a lot of methods to value thread schedulability in practical application. Rate monotonic scheduling algorithm is a widely used static priority scheduling algorithm. We discussed the thread schedulability in Huawei LiteOS.


2011 ◽  
Vol 219-220 ◽  
pp. 40-44
Author(s):  
Kun Shang ◽  
Huan Ding

Real-Time operating systems not only request the logical correctness, but also request the correct computing results in a set time and the instant response to the real-time tasks. Therefore scheduling algorithms of real-time operating systems become an important measure to determine the real-time capability of a system. In this paper, we discuss the dynamic priority scheduling algorithm –Priority Inheritance Scheduling Algorithm. Then we analyze the algorithm from two aspects: description and schedulability.


2013 ◽  
Vol 694-697 ◽  
pp. 2540-2544
Author(s):  
Zi Guo Fan ◽  
Rong Liang Wang ◽  
Peng Hao Yang

Multi-core processor technology is getting more and more common for both business and private use. However, the operating systems and applications are not keeping the same pace with multi-core hardware. In the mean while, to get better performance, more factors need to be considered under multi-core platform, e.g. load balance, cache, task relationship, etc. This paper focuses on making full use of multi-core processor through scheduling the tasks to proper core with CPU priority Algorithm which calculates a priority of each core when scheduling a task. With CPU Priority, it is easier to take interesting factors into account and combine several factors together. We did our work based on a scheduler simulator implemented with Python and we observed that, with CPU priority scheduling algorithm, it does suggest a flexible way to schedule the CPU assignment and is able to gain some satisfactory improvement on the response performance according to our simulation.


Urolithiasis ◽  
2020 ◽  
Author(s):  
Martino Marangella ◽  
Michele Petrarulo ◽  
Corrado Vitale ◽  
Piergiuseppe Daniele ◽  
Silvio Sammartano

AbstractEstimation of state of saturation with stone-forming salt represents a reliable tool to assess the overall risk. The available methods are based on computer-assisted ab initio calculations. Our earlier method URSUS was subsequently substituted by Lithorisk®, a software including visualization of risk profiles. Unfortunately, Lithorisk does not adapt to new versions of Windows® and Macintosh® Apple, neither runs on smartphones or tablets. We propose a novel version of the software which can be directly used online on any device equipped by different operating systems. Upon online connection and after registration, the software is ready for unlimited accesses, in either Italian, English or French. After digiting input variables (urea and creatinine also included) in a fixed dashboard, state of saturation is promptly given. In addition to state of saturation (ß) with calcium oxalate, brushite and uric acid, ß struvite and cystine are available. Both input variables and ß results are graphically depicted as green or red horizontal bars to indicate recommended values. The software was implemented with equations allowing to omit sulphate and ammonium excretion for users with difficult access to these measurements. This simplified version, tested for ßCaOx and ßBsh on 100 urine samples showed close correlation with the full version. The software gives a list of total and free concentrations and soluble complex species distribution. Results can be printed or saved as PDF. So, we propose an easily accessible software to estimate state of saturation usable on any operating system and personal device.


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. 


Author(s):  
Bishwo Prakash Pokharel

In an operating system, disk scheduling is the process of managing the I/O request to the secondary storage devices such as hard disk. The speed of the processor and primary memory has increased in a rapid way than the secondary storage. Seek time is the important factor in an operating system to get the best access time. For the better performance, speedy servicing of I/O request for secondary memory is very important. The goal of the disk-scheduling algorithm is to minimize the response time and maximize throughput of the system. This work analyzed and compared various basic disk scheduling techniques like First Come First Serve (FCFS), Shortest Seek Time First (SSTF), SCAN, LOOK, Circular SCAN (C-SCAN) and Circular LOOK (C-LOOK) along with the corresponding seek time. From the comparative analysis, the result show that C-LOOK algorithm give the least head movement and seek time in different cases as compared to other algorithm. Therefore, it maximizes the throughput for the storage devices.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Roberto Rodriguez-Zurrunero ◽  
Ramiro Utrilla ◽  
Elena Romero ◽  
Alvaro Araujo

Wireless Sensor Networks (WSNs) are a growing research area as a large of number portable devices are being developed. This fact makes operating systems (OS) useful to homogenize the development of these devices, to reduce design times, and to provide tools for developing complex applications. This work presents an operating system scheduler for resource-constraint wireless devices, which adapts the tasks scheduling in changing environments. The proposed adaptive scheduler allows dynamically delaying the execution of low priority tasks while maintaining real-time capabilities on high priority ones. Therefore, the scheduler is useful in nodes with rechargeable batteries, as it reduces its energy consumption when battery level is low, by delaying the least critical tasks. The adaptive scheduler has been implemented and tested in real nodes, and the results show that the nodes lifetime could be increased up to 70% in some scenarios at the expense of increasing latency of low priority tasks.


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1400
Author(s):  
Muhammad Adnan ◽  
Jawaid Iqbal ◽  
Abdul Waheed ◽  
Noor Ul Amin ◽  
Mahdi Zareei ◽  
...  

Modern vehicles are equipped with various sensors, onboard units, and devices such as Application Unit (AU) that support routing and communication. In VANETs, traffic management and Quality of Service (QoS) are the main research dimensions to be considered while designing VANETs architectures. To cope with the issues of QoS faced by the VANETs, we design an efficient SDN-based architecture where we focus on the QoS of VANETs. In this paper, QoS is achieved by a priority-based scheduling algorithm in which we prioritize traffic flow messages in the safety queue and non-safety queue. In the safety queue, the messages are prioritized based on deadline and size using the New Deadline and Size of data method (NDS) with constrained location and deadline. In contrast, the non-safety queue is prioritized based on First Come First Serve (FCFS) method. For the simulation of our proposed scheduling algorithm, we use a well-known cloud computing framework CloudSim toolkit. The simulation results of safety messages show better performance than non-safety messages in terms of execution time.


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