...Chapter 6: CPU Scheduling • • • Basic Concepts Scheduling Criteria Scheduling Algorithms Operating System Concepts 6.1 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. – Example: Alternating Sequence of CPU And I/O Bursts – In an I/O – bound program would have many very short CPU bursts. – In a CPU – bound program would have a few very long CPU bursts. Operating System Concepts 6.2 1 CPU Scheduler • The CPU scheduler (short-term scheduler) selects from among the processes in memory that are ready to execute, and allocates the CPU to one of them. • A ready queue may be implemented as a FIFO queue, priority queue, a tree, or an unordered linked list. • CPU scheduling decisions may take place when a process: 1. Switches from running to waiting state (ex., I/O request). 2. Switches from running to ready state (ex., Interrupts occur). 3. Switches from waiting to ready state (ex., Completion of I/O). 4. Terminates. • Scheduling under 1 and 4 is nonpreemptive; otherwise is called preemptive. • Under nonpreemptive scheduling, once the CPU has been allocated to a process, the process keeps the CPU until it releases the CPU either by terminating or by switching to the waiting state. Operating System Concepts 6.3 Dispatcher • Dispatcher module gives control of the CPU to the process selected by the short-term scheduler;...
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...CPU SCHEDULINGCPU scheduling in UNIX is designed to benefit interactive processes. Processes are given small CPU time slices by a priority algorithm that reduces to round-robin scheduling for CPU-bound jobs.The scheduler on UNIX system belongs to the general class of operating system schedulers known as round robin with multilevel feedback which means that the kernel allocates the CPU time to a process for small time slice, preempts a process that exceeds its time slice and feed it back into one of several priority queues. A process may need much iteration through the "feedback loop" before it finishes. When kernel does a context switch and restores the context of a process. The process resumes execution from the point where it had been suspended.Each process table entry contains a priority field. There is a process table for each process which contains a priority field for process scheduling. The priority of a process is lower if they have recently used the CPU and vice versa.The more CPU time a process accumulates, the lower (more positive) its priority becomes, and vice versa, so there is negative feedback in CPU scheduling and it is difficult for a single process to take all the CPU time. Process aging is employed to prevent starvation.Older UNIX systems used a 1-second quantum for the round- robin scheduling. 4.33SD reschedules processes every 0.1 second and recomputed priorities every second. The round-robin scheduling is accomplished by the -time-out mechanism, which tells...
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...system request to terminate the execution. * The CPU burst durations vary from process to process and computer to computer. * An I/O bound program has many very short CPU bursts. * A CPU bound program might have a few very long CPU bursts. Histogram of CPU-burst Times Types of Scheduling * The key to the multiprogramming is scheduling. There are four types of scheduling that an OS has to perform. These are: * Long Term scheduling * The long term scheduling determines which programs are admitted to the system for processing. Thus, it controls the level of multiprogramming. * Once admitted, a job or a user program becomes a process and is added to the queue for the short term scheduling (in some cases added to a queue for medium term scheduling). * Long term scheduling is performed when a new process is created. * The criteria used for long-term scheduling may include first-come-first serve, priority, expected execution time, and I/O requirements. * Medium-Term Scheduling * The medium-term scheduling is a part of swapping function. This is a decision to add a process to those that are at least partially in main memory and therefore available for execution. * The swapping-in decision is made on the need to manage the degree of multiprogramming and the memory requirements of the swapped-out process. * Short-Term Scheduling * A decision of which ready process to...
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...particular system Operating System Concepts – 8th Edition 5.3 Silberschatz, Galvin and Gagne ©2009 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 distribution Operating System Concepts – 8th Edition 5.4 Silberschatz, Galvin and Gagne ©2009 Alternating Sequence of CPU and I/O Bursts Operating System Concepts – 8th Edition 5.5 Silberschatz, Galvin and Gagne ©2009 Histogram of CPU-burst Times Operating System Concepts – 8th Edition 5.6 Silberschatz, Galvin and Gagne ©2009 CPU Scheduler Selects from among the processes in ready queue, and allocates the CPU to one of them Queue may be ordered in various ways Switches from running to waiting state Switches from running to ready state Switches from waiting to ready Terminates CPU scheduling decisions may take place when a process: 1. 2. 3. 4. Scheduling under 1 and 4 is nonpreemptive All other scheduling is preemptive Consider access to shared data Consider preemption while in kernel mode Consider interrupts occurring during crucial OS activities Operating System Concepts – 8th...
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...Study Guide to Accompany Operating Systems Concepts 8th Ed by Silberschatz, Galvin and Gagne By Andrew DeNicola, BU ECE Class of 2012 Figures Copyright © John Wiley & Sons 2012 Ch.1 - Introduction • • • • • • • • • • • • • • • • • • • • An OS is a program that acts as an intermediary between a user of a computer and the computer hardware Goals: Execute user programs, make the comp. system easy to use, utilize hardware efficiently Computer system: Hardware ↔ OS ↔ Applications ↔ Users (↔ = 'uses') OS is: ◦ Resource allocator: decides between conflicting requests for efficient and fair resource use ◦ Control program: controls execution of programs to prevent errors and improper use of computer Kernel: the one program running at all times on the computer Bootstrap program: loaded at power-up or reboot ◦ Stored in ROM or EPROM (known as firmware), Initializes all aspects of system, loads OS kernel and starts execution I/O and CPU can execute concurrently Device controllers inform CPU that it is finished w/ operation by causing an interrupt ◦ Interrupt transfers control to the interrupt service routine generally, through the interrupt vector, which contains the addresses of all the service routines ◦ Incoming interrupts are disabled while another interrupt is being processed ◦ Trap is a software generated interrupt caused by error or user request ◦ OS determines which...
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...US006785889B1 (12) United States Patent Williams (10) Patent N0.: US 6 9 785 9 889 B1 (45) Date of Patent: Aug. 31, 2004 (54) SYSTEM AND METHOD FOR SCHEDULING BANDWIDTH RESOURCES USINGA KALMAN ESTIMATOR WITH ACTIVE FEEDBACK 6,003,062 A * 12/1999 Greenberg et a1. ........ .. 709/104 6,105,053 A * 6,189,022 B1 * 6,263,358 B1 * 8/2000 Kimmel et a1. ..... .. 2/2001 Binns ............. .. 7/2001 Lee et a1. .... .. 709/105 709/100 .. 709/100 Inventor: Peter Williams, * Cited examiner (73) Assignee: Aurema, Inc., Cupertino, CA (US) _ _ _ _ Primary Examiner—Jack B. Harvey ( * ) Notice: SubJect to any disclaimer,~ the term of this Patent 15 extended or adlusted under 35 U'S'C' 154(k)) by 816 days‘ Assistant Examiner_Hai V_ Nguyen (74) Attorney, Agent, or Firm—Michael Hetherington; Nick Ulman; Woodside IP Group (21) Appl. N0.: 09/596,026 (22) Filed: (51) Int C17 (52) U ' ' (57) G06F 9/00 709040 ’ ’ 718/106’ ABSTRACT Jun. 15, 2000 A community of collaborative software agents Works together in a domain to provide functionality such as pro vision of communications services or control of a chemical process. A scheduler is built into each collaborative agent Ci """""""""""" ' """"""""""" " (58) (56) Field of Search """"""""" ’ 709/104 229 718/104; 106’ ’ Which schedules tasks allocated to that particular agent and tasks sub-allocated by the agent. The scheduler has a mecha nism for over-booking...
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...Teradata Database Release Summary Release 12.0 B035-1098-067A March 2008 The product or products described in this book are licensed products of Teradata Corporation or its affiliates. Teradata, BYNET, DBC/1012, DecisionCast, DecisionFlow, DecisionPoint, Eye logo design, InfoWise, Meta Warehouse, MyCommerce, SeeChain, SeeCommerce, SeeRisk, Teradata Decision Experts, Teradata Source Experts, WebAnalyst, and You’ve Never Seen Your Business Like This Before are trademarks or registered trademarks of Teradata Corporation or its affiliates. Adaptec and SCSISelect are trademarks or registered trademarks of Adaptec, Inc. AMD Opteron and Opteron are trademarks of Advanced Micro Devices, Inc. BakBone and NetVault are trademarks or registered trademarks of BakBone Software, Inc. EMC, PowerPath, SRDF, and Symmetrix are registered trademarks of EMC Corporation. GoldenGate is a trademark of GoldenGate Software, Inc. Hewlett-Packard and HP are registered trademarks of Hewlett-Packard Company. Intel, Pentium, and XEON are registered trademarks of Intel Corporation. IBM, CICS, RACF, Tivoli, z/OS, and z/VM are registered trademarks of International Business Machines Corporation. Linux is a registered trademark of Linus Torvalds. LSI and Engenio are registered trademarks of LSI Corporation. Microsoft, Active Directory, Windows, Windows NT, and Windows Server are registered trademarks of Microsoft Corporation in the United States and other countries. Novell and SUSE are registered trademarks...
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...University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University T.Y. PuneSemester V & VI of Pune of B.C.A. University University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune University of Pune Pattern 2008, w.e.f. 2010-11 Semester – V Course No. 501 502 503 504 505 506 Subject Name VB.NET or VB.NET Programming Internet Programming and Cyber Law Principals of Marketing Core Java Project work ( VB ) Computer Laboratory and Practical Work (.NET + Core Java ) Semester – VI Course No. 601 602 603 604 605 606 Subject Names E-Commerce Multimedia Systems Introduction to Syspro And Operating Systems Advance Java Project Work (Banking & Finance, Cost Analysis, Financial Analysis, Payroll, EDP, ERP etc.) Computer Laboratory and Practical Work (Multimedia + Advanced Java) University of Pune, T.Y. B.C.A., Semester V & VI 2 T.Y. B.C.A. Semester V Subject Name -: VB.NET or VB.NET Programming. Course Code -: 501 Sr. No. 1. TOPICS .NET Framework (Introduction to .NET Framework) 1.1 Introduction 1...
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...Chapter 1 Study Guide True/False Indicate whether the statement is true or false. ____ ____ ____ 1. End-user computing refers to the use of computers for both business and personal use. 2. The first computers used widely in businesses were available during the 1940s. 3. The goal of transaction processing on early computers was to replace as much manual processing of business information as possible with automated processing. 4. Among the reasons for the growth in decentralized computing was the availability of inexpensive personal computer hardware and productivity software. 5. The applications development backlog was due to the inability of computer professionals to design and write programs fast enough to keep up with the demand for new applications. 6. All knowledge workers are computer professionals. 7. A knowledge worker is another name for a computer user. 8. Use of a computer’s graphical user interface means that users no longer have to remember which command to enter to perform a task. 9. To operate a graphical user interface, a user types keyboard commands to tell a computer which tasks to perform. ____ ____ ____ ____ ____ ____ ____ 10. The Information Technology department is a modern name for the Data Processing department. ____ 11. Distributed computing links large-scale systems and personal computers to meet both organizational and individual worker needs. ____ 12. Computer departments in most organizations today are called data processing departments...
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...RESEARCH 2015 R E S E A R C H , 2 015 The Doctoral Programs at Harvard Business School educate scholars who make a difference in the world through rigorous academic research that influences practice. More than 140 strong, HBS doctoral students represent diverse backgrounds, degrees, undergraduate schools, and disciplines includ— ing economics, engineering, mathematics, physics, psychology, and sociology. They examine the most critical issues in business management through rigorous research, creating and disseminating new knowledge as the next generation of thought leaders. By the time they graduate, students will have authored and co-authored publications with faculty members, who often become important mentors, colleagues, and collaborators. ACCOUNTING AND MANAGEMENT Chattopadhyay, Akash , Matthew R. Lyle, and Charles C.Y. Wang. “Accounting Data, Market Values and the Cross-Section of Expected Returns Worldwide.” Working Paper, April 2015. (Revise and resubmit to Journal of Accounting and Economics.) Gow, Ian D., Sa-Pyung Sean Shin, and Suraj Srinivasan. “Activist Directors: Determinants and Consequences.” HBS Working Paper 14-120, June 2014. Gow, Ian D., Sa-Pyung Sean Shin, and Suraj Srinivasan. “Consequences to Directors of Shareholder Activism.” HBS Working Paper 14-071, February 2014. Ioannou, Ioannis, Shelley Xin Li, and George Serafeim. “The Effect of Target Difficulty and Incentives on Target Completion: The Case of Reducing Carbon Emissions.”...
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...Task 1 Element 1 Describe computer network types and standards. 1.1 The description distinguishes types of networks. Homogeneous Networks Homogeneous means similar, it is easy to administer and protect the homogeneous network configuration in networking. In a homogeneous network configuration, the similar operating environment is used to run the all systems. Same protocols are used to run the same operating environment and with the similar security attributes. A homogeneous network used a NIS+ master, is shown in the following figure. Figure (a) Homogeneous Network Heterogeneous Networks Heterogeneous means different, to run different network protocol a Trusted Solaris networks can be used. Different protocols are used to run the same operating environment and with the different security attributes and uses the different NIS (network information service). The following figure shows a typical heterogeneous network and some different protocols. There is a good example of heterogeneous network in networking term, computers with MS windows XP / windows 7 & UNIX, Linux, can communicate to each other by using different network protocols. Figure (b) Heterogeneous Network (Oracle, 2010) Wide Area Network Wide Area Network (WAN) is any network that crosses different far places like national boundaries. In WAN we can shares software and resources with connecting workstations and can Share information/files over a larger area A centralised WAN consist of a central...
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...Customer Satisfaction towards Retailers ICA, ICA NÄRA and COOP FORUM Author: Phuc Hong Lu Ian Grace.B. Lukoma Subject: Master Thesis in Business Administration 15 ECTS Program: Master of International Management Gotland University Spring semester 2011 Supervisor: Ph.D Bo Lennstrand ABSTRACT In the midst of stiff and fierce competition and increased number of grocery retail outlets providing a variety of products, customers have become accustomed to patronizing multiple outlets. Retailers have recognized this trend and are of the view that customer satisfaction plays a role in the success of business strategies. Therefore it has become important for grocery retail stores to try and manage customer satisfaction. This paper was thus developed to investigate the satisfaction levels of customers in supermarkets. Data was collected from three supermarkets in Visby, Gotland. The study examined the importance of overall dimensions and specific elements of customer satisfaction towards the measurement of satisfaction levels. In addition, comparative analysis was conducted between the three relative grocery stores. Customer satisfaction levels were measured. The highest percentage of customers of the whole sample belonged to medium level of satisfaction. The statistical result concluded that customers of ICA Nära and customers of ICA were higher satisfied than those of Coop Forum. The results showed that customers felt satisfied with Location, Staff courtesy and Reliability of supermarkets...
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...THE FOUR MOBILE TRAPS The Most Common Mistakes Made by Mobile Apps and Websites SUMMARY SUMMARY: FOUR COMMON MISTAKES PLAGUE MOBILE APPS AND WEBSITES Companies creating mobile apps and websites often underestimate how different the mobile world is. They assume incorrectly that they can create for mobile using the same design and business practices they learned in the computing world. As a result, they frequently struggle to succeed in mobile. These companies can waste large amounts of time and money as they try to understand why their mobile apps and websites don’t meet expectations. What’s worse, their awkward transition to mobile leaves them vulnerable to upstart competitors who design first for mobile and don’t have the same computing baggage holding them back. From giants like Facebook to the smallest web startup, companies are learning that the transition to mobile isn’t just difficult, it’s also risky. This whitepaper describes the four most common mistakes that companies make in mobile apps and websites. The traps were identified through thousands of mobile user tests run by UserTesting.com. The mistakes are common because they grow out of some of the best practices that make a company successful in the traditional computing world. The more successful you’ve been in traditional computing, the more likely you are to make these mistakes in mobile. In the pages that follow, we’ll describe the traps, how to recognize them, and what you can do...
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...UNIVERSITY OF MUMBAI Bachelor of Engineering Information Technology (Third Year – Sem. V & VI) Revised course (REV- 2012) from Academic Year 2014 -15 Under FACULTY OF TECHNOLOGY (As per Semester Based Credit and Grading System) University of Mumbai, Information Technology (semester V and VI) (Rev-2012) Page 1 Preamble To meet the challenge of ensuring excellence in engineering education, the issue of quality needs to be addressed, debated and taken forward in a systematic manner. Accreditation is the principal means of quality assurance in higher education. The major emphasis of accreditation process is to measure the outcomes of the program that is being accredited. In line with this Faculty of Technology of University of Mumbai has taken a lead in incorporating philosophy of outcome based education in the process of curriculum development. Faculty of Technology, University of Mumbai, in one of its meeting unanimously resolved that, each Board of Studies shall prepare some Program Educational Objectives (PEO‟s) and give freedom to affiliated Institutes to add few (PEO‟s) and course objectives and course outcomes to be clearly defined for each course, so that all faculty members in affiliated institutes understand the depth and approach of course to be taught, which will enhance learner‟s learning process. It was also resolved that, maximum senior faculty from colleges and experts from industry to be involved while revising the curriculum. I am happy to state...
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...International Journal of Electrical & Computer Sciences IJECS-IJENS Vol:12 No:04 25 Studying Main Differences Between Linux & Windows Operating Systems Lecturer/ Hadeel Tariq Al-Rayes Abstract—Comparisons between the Microsoft Windows and Linux computer operating systems are a long-running discussion topic within the personal computer industry. Throughout the entire period of the Windows 9x systems through the introduction of Windows 7, Windows has retained an extremely large retail sales majority among operating systems for personal desktop use, while Linux has sustained its status as the most prominent Free Software and Open Source operating system. After their initial clash, both operating systems moved beyond the user base of the personal computer market and share a rivalry on a variety of other devices, with offerings for the server and embedded systems markets, and mobile internet access. Linux and Microsoft Windows differ in philosophy, cost, versatility and stability, with each seeking to improve in their perceived weaker areas. Comparisons of the two operating systems tend to reflect their origins, historic user bases and distribution models. Index Term— Kernel, Linux, Operating Systems, Windows II. THE ESSENTIAL DIFFERENCES BETWEEN LINUX & WINDOWS (BEGINNERS LEVEL) 1- Drives don’t have letters, they have mountpoints The first thing that usually trips up people who come from Windows to Linux is that filesystems aren’t assigned letters the way they...
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