...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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...Chapter 5: CPU Scheduling Operating System Concepts – 8th Edition Silberschatz, Galvin and Gagne ©2009 Chapter 5: CPU Scheduling Basic Concepts Scheduling Criteria Scheduling Algorithms Thread Scheduling Multiple-Processor Scheduling Operating Systems Examples Algorithm Evaluation Operating System Concepts – 8th Edition 5.2 Silberschatz, Galvin and Gagne ©2009 Objectives To introduce CPU scheduling, which is the basis for multiprogrammed operating systems To describe various CPU-scheduling algorithms To discuss evaluation criteria for selecting a CPU-scheduling algorithm for a 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...
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...Case Studies 1. SOLUTION TO STARTING RIGHT CASE, CH. 3, PAGE 110 This is a decision-making-under-uncertainty case. There are two events: a favorable market (event 1) and an unfavorable market (event 2). There are four alternatives, which include do nothing (alternative 1), invest in corporate bonds (alternative 2), invest in preferred stock (alternative 3), and invest in common stock (alternative 4). The decision table is presented. Note that for alternative 2, the return in a good market is $30,000 (1 + 0.13)5 = $55,273. The return in a good market is $120,000, (4 x $30,000) for alternative 3, and $240,000, (8 x $30,000) for alternative 4. Payoff table Laplace Event 1 Alternativ e1 Alternativ e2 Alternativ e3 Alternativ e4 0 55,273 Event 2 0 – 10,00 0 – 15,00 0 – 30,00 0 Average Value 0.0 22,636.5 Minimu m 0 – 10,000 – 15,000 – 30,000 Maximu m 0 55,273 Hurwicz Value 0.00 – 2,819.9 7 –150.00 120,00 0 240,00 0 52,500.0 120,000 105,000. 0 240,000 –300.00 Regret table Maximum Alternative Alternative 1 Alternative 2 Alternative 3 Alternative 4 Event 1 240,000 184,727 120,000 0 Event 2 0 10,000 15,000 30,000 Regret 240,000 184,727 120,000 30,000 a. Sue Pansky is a risk avoider and should use the maximin decision approach. She should do nothing and not make an investment in Starting Right. b. Ray Cahn should use a coefficient of realism of 0.11. The best decision is to do nothing. c. Lila Battle should eliminate alternative 1 of doing nothing and apply the maximin...
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...Case Studies 1. SOLUTION TO STARTING RIGHT CASE, CH. 3, PAGE 110 This is a decision-making-under-uncertainty case. There are two events: a favorable market (event 1) and an unfavorable market (event 2). There are four alternatives, which include do nothing (alternative 1), invest in corporate bonds (alternative 2), invest in preferred stock (alternative 3), and invest in common stock (alternative 4). The decision table is presented. Note that for alternative 2, the return in a good market is $30,000 (1 + 0.13)5 = $55,273. The return in a good market is $120,000, (4 x $30,000) for alternative 3, and $240,000, (8 x $30,000) for alternative 4. Payoff table Laplace Hurwicz Event 1 Event 2 Average Value Minimu m Maximu m Value Alternativ e1 0 0 0.0 0 0 0.00 Alternativ e2 55,273 – 10,00 0 22,636.5 – 10,000 55,273 – 2,819.9 7 Alternativ e3 120,00 0 – 15,00 0 52,500.0 – 15,000 120,000 –150.00 Alternativ e4 240,00 0 – 30,00 0 105,000. 0 – 30,000 240,000 –300.00 Regret table Maximum Alternative Event 1 Event 2 Regret Alternative 1 240,000 0 240,000 Alternative 2 184,727 10,000 184,727 Alternative 3 120,000 15,000 120,000 Alternative 4 0 30,000 30,000 a. Sue Pansky is a risk avoider and should use the maximin decision approach. She should do nothing and not make an investment in Starting...
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...The John Warner School Faculty of Professional Studies BTEC Assignment Brief Qualification | Edexcel BTEC National Level 3 Subsidiary Diploma | Unit number and title | Unit 2 – Computer Systems | Assignment number and title | 1 – Components of a computer system | Start date | 21/9/15 | Hand in date | 1/11/15 | Assessor | WMG | Scenario You are a junior technician in a small business and you are responsible for the IT. The business has 10 computers in all comprised of desktop computers and a server. There are six employees based in the Head Office and your company have taken on a junior employee called Jamil who will be expected to help you out perform basic administrative tasks in the office as well as maintain the ICT systems. Task 1 – Computer hardware components You need to make sure Jamil has a reference guide for the machines in the business to help him understand the environment he will be working in and in case any components fail. You need to put together a presentation slideshow on internal computer components. a) You need to explain the function of internal hardware components of a computer b) Discuss how the components communicate with one another The components are: * Processor * RAM * Hard drive * Power supply unit * Fan * Heatsink * Motherboard * Graphic card and sound cards * CD/DVD drive This task will allow you to provide evidence for: P1 - Explain the function of computer...
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...Budgeting and management control systems Individual assignment #1 – Matteo Ambrogini CASE: Cafè Xaragua Questions 1) Prepare a forecast for the first year of operations using the information provided in the case. Clearly identify your assumptions. See the frame used to analyze the case in Exhibit 1, the forecast in Exhibit 2, a breakdown of costs calculations in Exhibit 3, a breakdown of “Equipment & Fixture” costs and time allocation of all fixed costs in Exhibit 4. ASSUMPTIONS MADE (refer to the framework shown in exhibit 1 to identify each element: Price, Quantity, Fixed costs, Variable costs): General Assumptions: I assumed the cafè to stay opened 50 weeks, 350 days per year. Price: All data available from the case. No assumptions needed. Quantity: 200-300 drinks per day, assumed 250 Assumed 1 drink per customer, so 250 customers per day 50% of customers purchasing a baked good, so 125 baked goods per day 10% of customers purchasing a bag of coffee, so 25 bags of coffee per day Fixed Costs: Assumptions on useful life of fixed assets and on allocation periods are reported in exhibit 4. The useful life of fixed assets and equipment has been estimated by research and personal experience. I assumed legal fees, permits etc. to be renewed every 10 years, the property to be improved and maintained every 10 years, the roaster installation cost to be allocated over time coherently to its assumed useful life of 5 years. Variable Costs: All data available from the case...
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...Programme Area of Computing BTEC Level 3 90-credit Diploma In Information Technology (QCF) Unit no: 2 | Learner group: C2250, C0183, C0177, C0186, C0184, C0185, | Unit title: Computer Systems | Learner name: | Date issued: W/C 26th January 2016 | Assessor name: Mark Dollan | Completion date: W/E 1st Feb 2016 | Written by: M Dollan | Submitted on: | Verified by: Karl Indans | Assignment title: System Software & Configuration (ref: L3-CS02) | In this assessment you will have opportunities to provide evidence against the following criteria. Indicate the page numbers where the evidence can be found also PPD (Personal and Professional Development) and EE | Grading Criteria | Criteria ref | To achieve the criteria the evidence must show that the student is able to: | Task | Evidence | Page | P2 | Explain the purpose of operating systems | 1 | Written | | P3 | Explain the purpose of different software utilities | 3 | Written | | P6 | Configure a computer system to meet user needs | 5 | Practical | | P7 | Test a configured computer system for functionality | 6 | Practical | | M1 | Compare the features and functions of different operating systems | 2 | Written | | M3 | Evaluate the performance of a computer system | 7 | Written | | D1 | Explain how software utilities can improve the performance of computer systems | 4 | Written | | This is an official course assessment and you must make a good attempt at all criteria available, you...
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...understanding of how gas turbines operates, and the parameters which influence their efficiency. Theory Apparatus The Gunt ET972 Small Gas Turbine Demonstration Unit is an educational instrument, designed with ergonomics in mind, and is equipped with a number of displays to convey performance information. Propane is used as the fuel. As small size and a range of options are required in an educational setting, efficiency is not a priority and hence suffers as the unit is optimised for practicality rather than power output. Gas turbines are effectively vibration free as there is no reciprocal motion as in a piston engine, have a very high power to weight ratio, and when coupled to an electrical generator, are used to account for unexpected rises in power electricity demand. Schematic diagram on the front side of the Gunt ET972 Small Gas Turbine Demonstration Unit, outlining the main controls and information displays to the user. Table of Results | | | | | | | Experiment No. | 1 | 2 | 3 | 4 | 5 | | Gas TG °C | 22.8 | 25.3 | 26.8 | 27.6 | 27.7 | | Gas Nozzle Pressure, PD [Barrel] | 0.64 | 0.78 | 0.89 | 0.98 | 1.1 | | Compressor Inlet, T1 [°C] | 32.3 | 33.4 | 32.8 | 33.2 | 34 | | Compressor Inlet, T2 [°C] | 79.2 | 88.4 | 97.7 | 103.2 | 111.1 | | Comb. Chamber Differential Pressure, ΔP [P2-P3] | 0.012 | 0.0136 | 0.0146 | 0.0154 | 0.0166 | | Turbine Inlet, T3 [°C] | 769 | 793 | 808 | 820 | 840 | | Turbine Inlet, P3 [Bar] | 0.56 | 0.63 | 0.73...
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...1. Deadlock (“deadly embrace”) is a system-wide tangle of resource requests that begins when 2 or more jobs are put on hold. • Each job is waiting for a vital resource to become available. • Needed resources are held by other jobs also waiting to run but can’t because they’re waiting for other unavailable resources. • The jobs come to a standstill. • The deadlock is complete if remainder of system comes to a standstill as well. • The resources can be categorized into physical and logical resources. The physical resources are printer, disk drive, cpu, memory, scanner etc. The logical resources are files. • Deadlock is more serious than indefinite postponement or starvation because it affects more than one job. • Because resources are being tied up, the entire system (not just a few programs) is affected. • Requires outside intervention (e.g., operators or users terminate a job) to resolved the deadlock. 2. Seven Cases of Deadlocks Case 1 Deadlocks on file requests Case 2 Deadlocks in databases Case 3 Deadlocks in dedicated device allocation Case 4 Deadlocks in multiple device allocation Case 5 Deadlocks in spooling Case 7 Deadlocks in disk sharing Case 8 Deadlocks in a network Case 1: Deadlocks on File Requests | |If jobs can request and hold files for duration of their...
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...|Qualification |Edexcel BTEC National Level 3 Extended Diploma in Business | |Unit number and title |Unit 39: International Business | |Learner Name | | |Assessor Name | | |Date issued |31/10/13 | Assessment criteria to be assessed in this assignment |Criteria Reference|To achieve the criteria the evidence must show that the learner is able to: |Task No. |Page No. | |P1 |Explain the international business environment in which a selected organisation operates |1.1 | | |P2 |Describe the mechanisms that regulate international trade |1.2 | | |P3 |Describe how the environment and culture of another country affects |1.5 | | | |a business operating internationally ...
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...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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...Cambridge TECHNICALS OCR LEVEL 3 CAMBRIDGE TECHNICAL CERTIFICATE/DIPLOMA IN IT COMPUTER NETWORKS R/601/7320 LEVEL 3 UNIT 7 GUIDED LEARNING HOURS: 60 UNIT CREDIT VALUE: 10 COMPUTER NETWORKS R/601/7320 LEVEL 3 UNIT 7 AIM OF THE UNIT This unit aims to give the learners an understanding of the key components, the network protocols and the services provided by network systems. Learners will develop skills required to ensure network security, gain an understanding to the functions of hardware and software components, the purpose, connections and connection devices and why network security is important. Networks are used not only in large organisations but in small businesses and homes. Learners will understand the types of network and the principles across LAN and WANs. They will understand the options for wired and wireless networks and the and appreciate the benefits and risks to businesses of a network. www.ocr.org.uk 2 Computer Networks Level 3 Unit 7 ASSESSMENT AND GRADING CRITERIA Learning Outcome (LO) Pass The assessment criteria are the pass requirements for this unit. Merit To achieve a merit the evidence must show that, in addition to the pass criteria, the learner is able to: Distinction To achieve a distinction the evidence must show that, in addition to the pass and merit criteria, the learner is able to: The learner will: 1 Know types of network systems and protocols The learner can: P1 describe the types of networks...
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...Notes CIMA Paper P2 Management Performance For exams in 2013 theexpgroup.com CIMA P2 Performance Management ExPress Notes Contents About ExPress Notes 1. 2. 3. 4. Pricing and Product Decisions Cost planning and analysis Budgeting and Management Control Control/Performance Measurement of Responsibility Centres 3 7 22 31 37 Page | 2 © 2013 The ExP Group. Individuals may reproduce this material if it is for their own private study use only. Reproduction by any means for any other purpose is prohibited. These course materials are for educational purposes only and so are necessarily simplified and summarised. Always obtain expert advice on any specific issue. Refer to our full terms and conditions of use. No liability for damage arising from use of these notes will be accepted by the ExP Group. theexpgroup.com CIMA P2 Performance Management ExPress Notes START About ExPress Notes We are very pleased that you have downloaded a copy of our ExPress notes for this paper. We expect that you are keen to get on with the job in hand, so we will keep the introduction brief. First, we would like to draw your attention to the terms and conditions of usage. It’s a condition of printing these notes that you agree to the terms and conditions of usage. These are available to view at www.theexpgroup.com. Essentially, we want to help people get through their exams. If you are a student for the CIMA exams and you are using these notes for yourself only, you...
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...LEVEL 3 - QCF BTEC ASSIGNMENT BRIEF Assignment Front Sheet | Qualification | Unit number and title | BTEC Level 3 90 Credit Diploma in Business | Unit 2: Business Resources | Learner name | Assessor name | | Sarah Price | Internal Verifier | Date Verified | | | Date issued | Hand in deadline | Submitted on | | | | | | Assignment title | Managing Human, Physical and Technical Resources (LO1&2) | In this assessment you will have opportunities to provide evidence against the following criteria. Indicate the page numbers where the evidence can be found. | Criteria reference | To achieve the criteria the evidence must show that the learner is able to: | | Task no. | | Evidence | P1 | Describe the recruitment documentation used in a selected organisation. | | 1 | | | P2 | Describe the main employability, personal and communication skills required when applying for a specific job role. | | 2 | | | P3 | Describe the main physical and technological resources required in the operation of a selected organisation. | | 3 | | | M1 | Explain how the management of human, physical and technological resources can improve the performance of a selected organisation | | 2&3 | | | M2 | Assess the importance of employability and personal skills in the recruitment and retention of staff in a selected organisation. | | 2 | | | D1 | Evaluate how managing resources and controlling budget costs can improve the performance...
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...LEVEL 3 - QCF BTEC ASSIGNMENT BRIEF Assignment Front Sheet | Qualification | Unit number and title | BTEC Level 3 90 Credit Diploma in Business | Unit 2: Business Resources | Learner name | Assessor name | | Sarah Price | Internal Verifier | Date Verified | | | Date issued | Hand in deadline | Submitted on | | | | | | Assignment title | Managing Human, Physical and Technical Resources (LO1&2) | In this assessment you will have opportunities to provide evidence against the following criteria. Indicate the page numbers where the evidence can be found. | Criteria reference | To achieve the criteria the evidence must show that the learner is able to: | | Task no. | | Evidence | P1 | Describe the recruitment documentation used in a selected organisation. | | 1 | | | P2 | Describe the main employability, personal and communication skills required when applying for a specific job role. | | 2 | | | P3 | Describe the main physical and technological resources required in the operation of a selected organisation. | | 3 | | | M1 | Explain how the management of human, physical and technological resources can improve the performance of a selected organisation | | 2&3 | | | M2 | Assess the importance of employability and personal skills in the recruitment and retention of staff in a selected organisation. | | 2 | | | D1 | Evaluate how managing resources and controlling budget costs can improve the performance...
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