DOCSLIB.ORG

Operating System

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Operating System OPERATING SYSTEM For COMPUTER SCIENCE OPERATING SYSTEM . SYLLABUS Processes, threads, interprocess communication, concurrency and synchronization. Deadlock. CPU scheduling. Memory management and virtual memory. File systems. ANALYSIS OF GATE PAPERS Exam Year 1 Mark Ques. 2 Mark Ques. Total 2003 2 5 12 2004 3 4 11 2005 - 2 4 2006 1 8 17 2007 2 6 14 2008 2 5 12 2009 2 5 12 2010 3 2 7 2011 4 2 8 2012 1 4 9 2013 2 4 10 2014 Set-1 2 3 8 2014 Set-2 1 3 7 2014 Set-3 1 3 7 2015 Set-1 2 4 10 2015 Set-2 2 3 8 2015 Set-3 2 2 6 2016 Set-1 1 4 9 2016 Set-2 1 3 7 2017 Set-1 2 2 6 2017 Set-2 2 2 6 2018 4 6 10 © Copyright Reserved by Gateflix.in No part of this material should be copied or reproduced without permission CONTENTS Topics Page No 1. PROCESS AND DEADLOCK 1.1 Process Concept 1 1.2 Process States 1 1.3 Degree of Multiprogramming 1 1.4 Process Control Block 1 1.5 Threads 1 1.6 CPU Scheduling 2 1.7 Scheduling Algorithms 3 1.8 Deadlock 8 1.9 Three Types of Problems 12 1.10 Procedure Consumer Problem 12 1.11 Printer And Spooler Problem 13 1.12 Solution to IPC/ Synchronization 13 1.13 Solution to Producer Consumer Problem using Semaphores 15 1.14 Solution to Reader & Writer Problem 15 Gate Questions 17 2. MEMORY MANAGEMENT 2.1 Introduction 53 2.2 Single Partition Allocation 55 2.3 External & Internal Fragmentation 56 2.4 Segmentation 58 2.5 Fragmentation 59 2.6 Virtual Memory 59 2.7 Page Replacement 60 2.8 Demand Paging 61 2.9 Page-Replacement 61 2.10 Counting Algorithms 63 2.11 Allocation of Frames 63 2.12 Thrashing 64 3. INTERRUPTS Gate Questions 65 3.1 Introduction 78 © Copyright Reserved by Gateflix.in No part of this material should be copied or reproduced without permission 3.2 Interrupts 78 3.3 Applications I/O Interface 79 3.4 Block and Character Devices 79 3.5 Kernel I/O subsystems 79 3.6 Performance 81 3.7 Stable-Storage Implementation 83 4. FILE-MANAGEMENTGate Questions 85 4.1 Introduction 88 4.2 File Concept 88 4.3 Access Methods 89 4.4 Single-Level Directory 91 4.5 Types of Access 91 4.6 Allocation Methods 92 4.7 Free-Space Management 94 4.8 Directory Implementation 94 Gate Questions 96 5. ASSIGNMENT QUESTIONS 99 © Copyright Reserved by Gateflix.in No part of this material should be copied or reproduced without permission 1 PROCESS & DEADLOCK 1.1 PROCESS suspended wait state (i.e. secondary storage).MTS reduces Process is just an executing program, degree of multiprogramming. including the current values of the program counter, registers, and variables. (c) STS (Short Term Scheduler): It is responsible to pick one process 1.2 PROCESS STATES from ready state and allocate it to Figure shows all process states. CPU.STS saves and loads context of a process in its PCB while switching. LTS: Job Scheduler MTS: Swapping STS: CPU Scheduler/Dispatcher STS is faster than LTS. Process with respect to their execution time are divided into two types: (a) CPU Bound Process: - Processes State 2, 3, and 4: Process in these states which require more CPU time are reside in RAM. called CPU Bound Process. The State 5, 6: Process is shifted to secondary process will spend more time in storage deliberately for some time. ready state. (b) IO Bound Process: - Processes 1.2.1 Three types of scheduler: which require more IO time are (a) LTS (Long Term Scheduler): It is the called IO Bound Process. responsibility of LTS to create a process and bring it in ready state. 1.3 Degree of Multiprogramming LTS decides which programs are The number of processes in the memory at admitted to system for execution. any point of time is called degree of multiprogramming. LTS should select good (b) MTS (Medium Term Scheduler): Its combination of CPU bound and IO bound responsibility is in two cases. When processes. LTS controls degree of ready stated becomes crowded so multiprogramming. that OS doesn’t have resources (RAM) to accommodate large 1.4 PROCESS CONTROL BLOCK number of processes in ready state, Every process has its own PCB. PCB is they can be moved by MTS to stored in RAM. suspended_ready state. Attributes: pid, process state, PC (program Also, when resources (RAM) gets counter),GPR(general purpose exhausted in wait state due to registers),Priority, List of open files, crowding, MTS shifts them to Protection & security. © Copyright Reserved by Gateflix.in No part of this material should be copied or reproduced without permission The set of these attributes is called context. Program Counter. Thread share data, code, Context is stored in PCB. memory, files, address space, File descriptor table, so on. 1.5 THREADS Threads are light weight processes. Each thread has its own Stack, Registers and User Level Threads Kernel Level Threads User level threads are dependent. Kernel level threads are independent. They are faster. They are comparatively slower but faster than a process. They are scheduled by thread library. They are scheduled by OS. They have less context. They have more context. Blocking IO calls: If one thread Non-Blocking IO calls: If one thread other thread of that process can run. blocks for IO, OS schedules another for execution. 1.6 CPU SCHEDULING (b) Burst Time SCHEDULING CRITERIA The time required for the process to complete its execution is called Burst The scheduling criteria that are used Time. includes (c) Completion Time The time when the process has i) CPU utilization completed its execution is called The CPU should be kept as busy as completion time. possible. CPU utilization may range (d) Turnaround time from 0 to 100 per cent. In a real system, The interval from the time of it should range from 40 per cent (for a submission of a process to the time of lightly loaded system) to 90 per cent completion is the turnaround time. TAT (for a heavily used system). = CT – WT. (e) Waiting time ii) Throughput The amount of time a process spends If the CPU is busy executing processes, waiting in the ready queue. then work is being done. One measure WT = TAT-BT. of work is the number of processes that (f) Response time are completed per time unit, called Response time, is the amount of time it throughput. For long processes, this takes to start responding, but not the rate may be one. time that it takes to output that response. The turnaround time is Various Time Measures related to generally limited by the speed of the CPU Scheduling: output device. The goal is to maximize CPU (a) Arrival Time Utilization, minimize average Turn The time when the process arrived into ready state is called arrival time. © Copyright Reserved by Gateflix.in No part of this material should be copied or reproduced without permission around Time, and minimize Waiting This reduction is substantial. Thus, the Time of processes. average waiting time under a FCFS policy is generally not minimal. 1.7 SCHEDULING ALGORITHMS The FCFS scheduling algorithm is non- preemptive. Once, the CPU has been 1.7.1 First-Come, First-Served allocated to a process, that process keeps Scheduling (FCFS) the CPU until it releases the CPU, either by Criteria: Arrival Time terminating or by requesting I/O. Mode : Non Preemptive Data Structure: Queue 1.7.2 Shortest –Job-First Scheduling Tie Breaker : Process Number (SJF) The average waiting time under the FCFS Criteria: Burst Time policy, however, is often quite long. Mode : Non Preemptive Consider the following set of processes Data Structure: Min Heap that arrive at time 0, with the length of the Tie Breaker : Arrival Time CPU- burst time given in milliseconds: Shortest Job First has minimum average waiting time among all CPU scheduling PROC ARRIVA BURS CT TA W algorithms. ESS L TIME T T T Consider the following set of process, with TIME the length of the CPU burst time given in P1 0 24 24 24 0 milliseconds: P2 0 3 27 27 24 PROCESS BURST TIME P3 0 3 30 30 27 P1 6 P2 8 P3 7 GANTT CHART: P4 3 Using SJF scheduling, we would schedule P1 P2 P3 these processes according the following 0 24 25 27 28 30 Gantt chart: Now, the waiting time is 0 milliseconds for P4 P1 P3 P2 process P1, 24 milliseconds for process P2, 0 3 9 16 24 and 27 milliseconds for process P3. Thus, 0+24+27 The waiting time is 3 milliseconds for the average waiting time = = 3 process P1, 16 milliseconds for process P2, 17milliseconds. 9 milliseconds for process P3, and 0 This example also shows Convoy effect. milliseconds for process P4. FCFS suffers from convoy effect. Thus, the average waiting time = If the processes arrive in the order P2, P3, 3 16 9 0 P1, however, the results will be as shown in 4 = 7 milliseconds. the following Gantt chart: If we were using the FCFS scheduling P2 P3 P1 scheme, then the average waiting time 0 3 6 30 would be 10.25 milliseconds. The SJF scheduling algorithm is provably 6+0+3 Now, the average waiting time = = 3 optimal, in that it gives the minimum 3milliseconds. average waiting time for a given set of © Copyright Reserved by Gateflix.in No part of this material should be copied or reproduced without permission processes.
Load more

Recommended publications
  • Definition Process Scheduling Queues
    Dear Students Due to the unprecedented situation, Knowledgeplus Training center is mobilized and will keep accompanying and supporting our students through this difficult time. Our Staff will be continuously, sending notes and exercises on a weekly basis through what’s app and email. Students are requested to copy the notes and do the exercises on their copybooks. The answers to the questions below will be made available on our website on knowledgeplus.mu/support.php. Please note that these are extra work and notes that we are providing our students and all classes will be replaced during the winter vacation. We thank you for your trust and are convinced that, together, we will overcome these troubled times Operating System - Process Scheduling Definition The process scheduling is the activity of the process manager that handles the removal of the running process from the CPU and the selection of another process on the basis of a particular strategy. Process scheduling is an essential part of a Multiprogramming operating systems. Such operating systems allow more than one process to be loaded into the executable memory at a time and the loaded process shares the CPU using time multiplexing. Process Scheduling Queues The OS maintains all PCBs in Process Scheduling Queues. The OS maintains a separate queue for each of the process states and PCBs of all processes in the same execution state are placed in the same queue. When the state of a process is changed, its PCB is unlinked from its current queue and moved to its new state queue. The Operating System maintains the following important process scheduling queues − • Job queue − This queue keeps all the processes in the system.
    [Show full text]
  • This Item Is the Archived Peer-Reviewed Author-Version Of
    This item is the archived peer-reviewed author-version of: Analyzing queues with customer differentiation using matrix analytic methods Reference: van Velthoven Jeroen.- Analyzing queues with customer differentiation using matrix analytic methods Antwerpen, Universiteit Antwerpen. Faculteit Wetenschappen. Departement Wiskunde & Informatica, 2008, 179 p. Handle: http://hdl.handle.net/10067/1109350151162165141 Institutional repository IRUA Faculteit Wetenschappen Departement Wiskunde & Informatica Analyzing Queues with Customer Differentiation using Matrix Analytic Methods Een analyse van wachtrijsystemen met differentiatie in klanten gebruikmakend van matrix analytische methodes Proefschrift voorgelegd tot het behalen van de graad van doctor in de Wetenschappen aan de Universiteit Antwerpen, te verdedigen door Jeroen VAN VELTHOVEN Promotor: Prof. dr. Benny Van Houdt Copromotor: Prof. dr. Chris Blondia Antwerpen, 2008 Contents Preface xi Acknowledgements xiii Notations and Acronyms xv Summary and Organization xvii I Introduction1 1 Queueing Theory and Markov Chains3 1.1 Markov Chains...................................4 1.2 Queueing Theory..................................6 1.2.1 Arrival Process...............................6 1.2.2 Scheduling Discipline............................7 1.2.3 Service Process...............................8 1.2.4 Some Basic Queueing Systems......................9 1.2.5 Customer Differentiation..........................9 2 Matrix Analytic Methods 11 2.1 Structured Processes................................ 12 2.1.1 M/G/1 and GI/M/1 Type Markov Chains................ 12 2.1.2 Quasi-Birth-Death Markov Chains.................... 12 2.1.3 Tree-Like Processes............................. 14 2.2 The D-MAP/PH/1 Queue............................. 16 2.2.1 The Discrete-Time Markovian Arrival Process.............. 16 2.2.2 Phase-Type Service Time......................... 17 2.2.3 Modeling the D-MAP/PH/1 Queue................... 18 II Steady State Analysis 19 3 Impatient Customers 21 3.1 Related Work...................................
    [Show full text]
  • CPU Scheduling
    Chapter 5: CPU Scheduling Operating System Concepts – 10th Edition Silberschatz, Galvin and Gagne ©2018 Chapter 5: CPU Scheduling Basic Concepts Scheduling Criteria Scheduling Algorithms Thread Scheduling Multi-Processor Scheduling Real-Time CPU Scheduling Operating Systems Examples Algorithm Evaluation Operating System Concepts – 10th Edition 5.2 Silberschatz, Galvin and Gagne ©2018 Objectives Describe various CPU scheduling algorithms Assess CPU scheduling algorithms based on scheduling criteria Explain the issues related to multiprocessor and multicore scheduling Describe various real-time scheduling algorithms Describe the scheduling algorithms used in the Windows, Linux, and Solaris operating systems Apply modeling and simulations to evaluate CPU scheduling algorithms Operating System Concepts – 10th Edition 5.3 Silberschatz, Galvin and Gagne ©2018 Basic Concepts Maximum CPU utilization obtained with multiprogramming CPU–I/O Burst Cycle – Process execution consists of a cycle of CPU execution and I/O wait CPU burst followed by I/O burst CPU burst distribution is of main concern Operating System Concepts – 10th Edition 5.4 Silberschatz, Galvin and Gagne ©2018 Histogram of CPU-burst Times Large number of short bursts Small number of longer bursts Operating System Concepts – 10th Edition 5.5 Silberschatz, Galvin and Gagne ©2018 CPU Scheduler The CPU scheduler selects from among the processes in ready queue, and allocates the a CPU core to one of them Queue may be ordered in various ways CPU scheduling decisions may take place when a
    [Show full text]
  • Scheduling Algorithm for Grid Computing Using Shortest Job First with Time Quantum
    Sudan University of Science and Technology Collage of Graduate Studies College of Engineering Scheduling Algorithm for Grid Computing using Shortest Job First with Time Quantum خوارزمية الجدولة للحوسبة الشبكية بإستخدام العمليات اﻷقصر أوﻻ مع الزمن الكمي A thesis submitted in partial fulfillment of the requirements for the degree of M.SC.in computer and networks engineering By: Raham Hashim Yosuf Supervised by: Dr. Rania A. Mokhtar August 2017 Initiation اﻷية قال هللا تعالى: {أَ َّم ْن ُه َو َقانِ ٌت آنَا َء اللَّ ْي ِل َسا ِجدًا َو َقائِ ًما َي ْحذَ ُر ا ْْل ِخ َرةَ َويَ ْر ُجو َر ْح َمةَ َربِ ِه قُ ْل َه ْل يَ ْستَ ِوي الَّ ِذي َن يَ ْع َل ُمو َن َوالَّ ِذي َن َﻻ َي ْع َل ُمو َن إِنَّ َما يَتَذَ َّك ُر أُولُو ا ْﻷَْلبَا ِب } صدق هللا العظيم سورة الزمر اْلية )9( I Dedication Dedicated to My parents, my sisters And to my friends To everyone who tried to guide me to A better life….. With my love II Acknowledgement My thanks for Allah After that I would like to thanks my university Sudan University of science and Technology and my college of Graduate Studies Electronics Engineering Department. And my teachers for inspiring me this project. I owe my profound gratitude to my thesis supervisor Dr. Rania A.Mokhtar for her valuable guidance, supervision and persistent encouragement. Due to the approach adopted by her in handling my thesis and the way she gave me freedom to think about different things, I was able to do the constructive thesis.
    [Show full text]
  • Comprehensive Examinations in Computer Science 1872 - 1878
    COMPREHENSIVE EXAMINATIONS IN COMPUTER SCIENCE 1872 - 1878 edited by Frank M. Liang STAN-CS-78-677 NOVEMBER 1078 (second Printing, August 1979) COMPUTER SCIENCE DEPARTMENT School of Humanities and Sciences STANFORD UNIVERSITY COMPUTER SC l ENCE COMPREHENSIVE EXAMINATIONS 1972 - 1978 b Y the faculty and students of the Stanford University Computer Science Department edited by Frank M. Liang Abstract Since Spring 1972, the Stanford Computer Science Department has periodically given a "comprehensive examination" as one of the qualifying exams for graduate students. Such exams generally have consisted of a six-hour written test followed by a several-day programming problem. Their intent is to make it possible to assess whether a student is sufficiently prepared in all the important aspects of computer science. This report presents the examination questions from thirteen comprehensive examinations, along with their solutions. The preparation of this report has been supported in part by NSF grant MCS 77-23738 and in part by IBM Corporation. Foreword This report probably contains as much concentrated computer science per page as any document In existence - it is the result of thousands of person-hours of creative work by the entire staff of Stanford's Computer Science Department, together with dozens of h~ghly-talented students who also helped to compose the questions. Many of these questions have never before been published. Thus I think every person interested in computer science will find it stimulating and helpful to study these pages. Of course, the material is so concentrated it is best not taken in one gulp; perhaps the wisest policy would be to keep a copy on hand in the bathroom at all times, for those occasional moments when inspirational reading is desirable.
    [Show full text]
  • Organisasi Komputer
    STMIK JAKARTA STI&K ORGANISASI KOMPUTER BUKU AJAR Aqwam Rosadi Kardian. 2009 ORGANISASI KOMPUTER 2009 BUKU AJAR ORGANISASI KOMPUTER STMIK JAKARTA STI&K 2009 Organisasi Komputer - Aqwam Rosadi Kardian. Hal- 2 ORGANISASI KOMPUTER 2009 EVOLUSI ABAD INFORMASI DAN SEJARAH KOMPUTER I. EVOLUSI ABAD INFORMASI A. ASPEK ABAD PERTANIAN Periode < 1800 Pekerja Petani Perpaduan Manusia & tanah Peralatan Tangan B. ASPEK ABAD INDUSTRI Periode 1800 – 1957 Pekerja Pegawai pabrik Perpaduan Manusia & mesin Peralatan Mesin C. ASPEK ABAD INFORMASI Periode 1957 – sekarang Pekerja Pekerja terdidik Perpaduan Manusia & manusia Peralatan Teknologi Informasi D. MASYARAKAT INFORMASI suatu masyarakat dimana lebih banyak orang bekerja dalam bidang penanganan informasi dari pada bidang pertanian dan industri. E. KARAKTERISTIK ABAD INFORMASI Munculnya masyarakat berbasis informasi Bisnis tergantung pada TI Adanya transformasi proses kerja Re-engineers proses bisnis yang konvensional Keberhasilannya bergantung pada efektivitas pemanfaatannya. TI melekat pada banyak produk & pelayanan Organisasi Komputer - Aqwam Rosadi Kardian. Hal- 3 ORGANISASI KOMPUTER 2009 F. DEFINISI TEKNOLOGI INFORMASI Teknologi Informasi suatu istilah yang menunjukkan berbagai macam hal dan kemampuan yang digunakan dalam pembentukan, penyimpanan, dan penyebaran informasi. TI mencakup : Komputer Jaringan Komunikasi Consumer Electronics ‘Know-How’ F.1. KOMPUTER Komputer suatu sistem elektronik yang dapat di-program (di-instruksi) untuk menerima, memproses, menyimpan dan menyajikan data dan informasi Sejarah Singkat Komputer A. Sejarah perkembangan komputer dari tahun sebelum masehi antara lain : Tahun 3000 SM, bilangan mulai dipakai. Tahun 2600 SM, dikembangakan suatu alat bantu untuk menghitung yaitu “ABACUS”. Tahun 1642 BLAISE PASCAL berhasil membuat alat hitung mekanik yang dapat melaksanakan penambahan dan pengurangan sampai bilangan terdiri dari 6 angka. Tahun 1694 GOTFRIED WILHELM LEIBITZ berhasil menemukan mesin yang dapat mengendalikan.
    [Show full text]
  • Scheduling Scheduling
    Scheduling Scheduling 1/51 Learning Objectives Scheduling I To understand the role of a scheduler in an operating system I To understand the scheduling mechanism I To understand scheduling strategies such as non-preemptive versus preemptive. I To be able to explain various scheduling algorithms like first-come first-served, round robin, priority-based etc I To examine commonly using schedulers on Linux and Microsoft Windows. 2/51 Scheduler Scheduling I Scheduler allocates CPU(s) to threads and processes. This action is known as scheduling. I The scheduler is a part of the process manager code that handles scheduling. 3/51 Scheduling Mechanisms Scheduling I The scheduling mechanism determines when it is time to multiplex the CPU. It handles the removal of a running process from the CPU and the selection of another process based on a particular scheduling policy. I The scheduling policy determines when it is time for a process to be removed from the CPU and which ready process should be allocated to the CPU next. I A scheduler has three components: the enqueuer, the dispatcher, and the context switcher. The context switcher is different for voluntary versus involuntary process switching styles. I The enqueuer places a pointer to a process descriptor of a process that just got ready into the ready list. I The context switcher saves the contents of all processor registers for the process being removed from the CPU in its process descriptor. Is invoked either by the process or by the interrupt handler. I The dispatcher selects one of the several ready processes enqueued in the ready list and then allocates the CPU to the process by performing another context switch from itself to the selected process.
    [Show full text]
  • Scheduling CS 111 Operating Systems Peter Reiher
    Scheduling CS 111 Operating Systems Peter Reiher CS 111 Lecture 6 Fall 2015 Page 1 Outline • What is scheduling? – What are our scheduling goals? • What resources should we schedule? • Example scheduling algorithms and their implications CS 111 Lecture 6 Fall 2015 Page 2 What Is Scheduling? • An operating system often has choices about what to do next • In particular: – For a resource that can serve one client at a time – When there are multiple potential clients – Who gets to use the resource next? – And for how long? • Making those decisions is scheduling CS 111 Lecture 6 Fall 2015 Page 3 OS Scheduling Examples • What job to run next on an idle core? – How long should we let it run? • In what order to handle a set of block requests for a disk drive? • If multiple messages are to be sent over the network, in what order should they be sent? CS 111 Lecture 6 Fall 2015 Page 4 How Do We Decide How To Schedule? • Generally, we choose goals we wish to achieve • And design a scheduling algorithm that is likely to achieve those goals • Different scheduling algorithms try to optimize different quantities • So changing our scheduling algorithm can drastically change system behavior CS 111 Lecture 6 Fall 2015 Page 5 The Process Queue • The OS typically keeps a queue of processes that are ready to run – Ordered by whichever one should run next – Which depends on the scheduling algorithm used • When time comes to schedule a new process, grab the first one on the process queue • Processes that are not ready to run either: – Aren’t in that queue –
    [Show full text]
  • COS 318: Operating Systems CPU Scheduling
    COS 318: Operating Systems CPU Scheduling Jaswinder Pal Singh Computer Science Department Princeton University (http://www.cs.princeton.edu/courses/cos318/) Today’s Topics u CPU scheduling basics u CPU scheduling algorithms 2 When to Schedule? u Process/thread creation u Process/thread exit u Process thread blocks (on I/O, synchronization) u Interrupt (I/O, clock) 3 Preemptive and Non-Preemptive Scheduling Terminate Exited (call scheduler) Scheduler dispatch Running Block for resource (call scheduler) Yield, Interrupt (call scheduler) Ready Blocked Create Resource free, I/O completion interrupt (move to ready queue) 4 Scheduling Criteria u Assumptions l One process per user and one thread per process l Processes are independent u Goals for batch and interactive systems l Provide fairness l Everyone makes some progress; no one starves l Maximize CPU utilization • Not including idle process l Maximize throughput • Operations/second (min overhead, max resource utilization) l Minimize turnaround time • Batch jobs: time to execute (from submission to completion) l Shorten response time • Interactive jobs: time response (e.g. typing on a keyboard) l Proportionality • Meets user’s expectations Scheduling Criteria u Questions: l What are the goals for PCs versus servers? l Average response time vs. throughput l Average response time vs. fairness Problem Cases u Completely blind about job types l Little overlap between CPU and I/O u Optimization involves favoring jobs of type “A” over “B” l Lots of A’s? B’s starve u Interactive process trapped
    [Show full text]
  • CPU Scheduling
    CPU Scheduling CSE 2431: Introduction to Operating Systems Instructor: Adam C. Champion, Ph.D. Reading: Chapter 5, [OSC] (except Sections 5.7.2, 5.8) 1 Contents • Why Scheduling? • Basic Concepts of Scheduling • Scheduling Criteria • A Basic Scheduling Algorithm (FCFS) • Scheduling Algorithms (SJF, RR, etc.) • Thread Scheduling 2 Why Scheduling? • Deciding which process/thread should occupy the resource (CPU, disk, etc.) (CPU (horsepower)) I want to ride it Whose turn is it? Process 1 Process 2 Process 3 3 Contents • Why Scheduling? • Basic Concepts of Scheduling • Scheduling Criteria • A Basic Scheduling Algorithm (FCFS) • Scheduling Algorithms (SJF, RR, etc.) • Thread Scheduling 4 When to Schedule? 5 Contents • Why Scheduling? • Basic Concepts of Scheduling • Scheduling Criteria • Basic Scheduling Algorithm (FCFS) • Scheduling Algorithms (SJF, RR, etc.) • Thread Scheduling 6 Scheduling Objectives • Fairness (nobody cries) • Priority (ladies first) • Efficiency (make best use of equipment) • Encourage good behavior (good boy/girl) • Support heavy loads (degrade gracefully) • Adapt to different environments (interactive, real-time, multimedia) 7 Performance Criteria • Fairness: No starvation • Efficiency: keep resources as busy as possible • Throughput: # of processes completed in unit time • Turnaround time (also called elapsed time): Amount of time to complete a certainprocess from its beginning • Waiting Time: Amount of time process has been waiting in ready queue • Response Time: Amount of time from when a request was first submitted until first response is produced. • Policy Enforcement: Enforcing that stated policy is carried out • Proportionality: Meet users' expectations 8 • Meeting Deadlines: Avoid losing data Different Systems, Different Foci • For all – Fairness, policy enforcement, resource balance • Batch Systems – Max throughput, min turnaround time, max CPU utilization • Interactive Systems – Min Response time, best proportionality • Real-Time Systems – predictability, meeting deadlines 9 Preemptive vs.
    [Show full text]
  • A Survey on Several Job Scheduling Techniques in Cloud Computing
    Journal of Network Communications and Emerging Technologies (JNCET) www.jncet.org Volume 8, Issue 4, April (2018) A Survey on Several Job Scheduling Techniques in Cloud Computing Dr. Karambir Faculty of Computer Science and Engineering, Department of Computer Science and Engineering, University Institute of Engineering and Technology, Kurukshetra University, 136119, Kurukshetra, Haryana, India. Charul Chugh M. Tech. (Computer Engineering), University Institute of Engineering and Technology, Kurukshetra University, 136119, Kurukshetra, Haryana, India. Abstract – Cloud computing is one of the upcoming latest new business presentations [2]. computing paradigm where applications and data services are provided over the Internet. Cloud computing is attractive to A. Advantages of Cloud Computing business owners as it eliminates the requirement for users to plan Cloud computing makes it easier for enterprises to scale ahead for provisioning, and allows enterprises to start from the small and increase resources only when there is a rise in service their services – which are increasingly reliant on accurate demand. While dealing with cloud computing, a number of issues information – according to client demand. Since the are confronted like heavy load or traffic while computation. Job computing resources are managed through software, they scheduling is one of the answers to these issues. The main can be deployed very fast as new requirements arise [3] advantage of job scheduling algorithm is to achieve a high [23]. performance computing and the best system throughput. Job scheduling is most important task in cloud computing It dramatically lowers the cost of entry for smaller firms environment because user have to pay for resources used based trying to benefit from compute-intensive business analytics upon time.
    [Show full text]
  • Attendance Using Palm Print Technology
    International Conference On Emanations in Modern Engineering Science and Management (ICEMESM-2017) ISSN: 2321-8169 Volume: 5 Issue: 3 01 - 04 ____________________________________________________________________________________________________________________ Attendance Using Palm Print Technology Upasana Ghosh Dastidar, Nikhita Jogi, Milan Bansod, Payal Madamwar Guided By: Prof Priyanka Jalan. Department of Computer Engineering, Bapurao Deshmukh Collage of Engineering, Sewagram, Wardha, Maharashtra, India Abstract: Today students’ (class) attendance became more important part for any organizations/institutions. The conventional method of taking attendance by calling names or signing on paper is very time consuming and insecure, hence inefficient. This paper presents the manual students’ attendance management into computerized system for convenience or data reliability. So, the system is developed by the integration of ubiquitous computing systems into classroom for managing the students’ attendance using palm print scanner. The system is designed to implement an attendance management system based on palm print scanner which students need to use their palm to success the attendance where only authentic student can be recorded the attendance during the class. This system takes attendance electronically with the help of the webcam, and the records the attendance in a database. Students’ roll call percentages and their details are easily seen via Graphical User Interface (GUI).This system will have the required databases for students’ attendance,
    [Show full text]