Chapter 7: Deadlocks!
|
|
|
- Lauren Owen
- 8 years ago
- Views:
Transcription
1 The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. Chapter 7: Deadlocks!
2 Chapter 7: Deadlocks! The Deadlock Problem System Model Deadlock Characterization Methods for Handling Deadlocks Deadlock Prevention Deadlock Avoidance Deadlock Detection Recovery from Deadlock 7.2! Silberschatz, Galvin and Gagne 2005!
3 Chapter Objectives! To develop a description of deadlocks, which prevent sets of concurrent processes from completing their tasks To present a number of different methods for preventing or avoiding deadlocks in a computer system. 7.3! Silberschatz, Galvin and Gagne 2005!
4 The Deadlock Problem! A set of blocked processes each holding a resource and waiting to acquire a resource held by another process in the set. Example System has 2 tape drives. P 0 and P 1 each hold one tape drive and each needs another one. Example semaphores A and B, initialized to 1 P 0 P 1 wait (A);!!wait(B)! wait (B);!!wait(A)! 7.4! Silberschatz, Galvin and Gagne 2005!
5 Bridge Crossing Example! Traffic only in one direction. Each section of a bridge can be viewed as a resource. If a deadlock occurs, it can be resolved if one car backs up (preempt resources and rollback). Several cars may have to be backed up if a deadlock occurs. Starvation is possible. 7.5! Silberschatz, Galvin and Gagne 2005!
6 System Model! Resource types R 1, R 2,..., R m CPU cycles, memory space, I/O devices! Each resource type R i has W i instances. Each process utilizes a resource as follows: request use release 7.6! Silberschatz, Galvin and Gagne 2005!
7 Deadlock Characterization! Deadlock can arise if four conditions hold simultaneously. Mutual exclusion: only one process at a time can use a resource. Hold and wait: a process holding at least one resource is waiting to acquire additional resources held by other processes. No preemption: a resource can be released only voluntarily by the process holding it, after that process has completed its task. Circular wait: there exists a set {P 0, P 1,, P 0 } of waiting processes such that P 0 is waiting for a resource that is held by P 1, P 1 is waiting for a resource that is held by!p 2,, P n 1 is waiting for a resource that is held by P n, and P 0 is waiting for a resource that is held by P ! Silberschatz, Galvin and Gagne 2005!
8 Resource-Allocation Graph! A set of vertices V and a set of edges E. V is partitioned into two types: P = {P 1, P 2,, P n }, the set consisting of all the processes in the system. R = {R 1, R 2,, R m }, the set consisting of all resource types in the system. request edge directed edge P 1 R j! assignment edge directed edge R j P i 7.8! Silberschatz, Galvin and Gagne 2005!
9 Resource-Allocation Graph (Cont.)! Process Resource Type with 4 instances P i requests instance of R j P i! P i is holding an instance of R j! R j! P i R j! 7.9! Silberschatz, Galvin and Gagne 2005!
10 Example of a Resource Allocation Graph! 7.10! Silberschatz, Galvin and Gagne 2005!
11 Will there be a deadlock here?! 7.11! Silberschatz, Galvin and Gagne 2005!
12 Resource Allocation Graph With A Cycle But No Deadlock! 7.12! Silberschatz, Galvin and Gagne 2005!
13 Basic Facts! If graph contains no cycles no deadlock. If graph contains a cycle if only one instance per resource type, then deadlock. if several instances per resource type, possibility of deadlock. 7.13! Silberschatz, Galvin and Gagne 2005!
14 Methods for Handling Deadlocks! Ensure that the system will never enter a deadlock state. Allow the system to enter a deadlock state and then recover. Ignore the problem and pretend that deadlocks never occur in the system; used by most operating systems, including UNIX. 7.14! Silberschatz, Galvin and Gagne 2005!
15 The Methods (continued)! Deadlock Prevention Deadlock Avoidance Deadlock Detection 7.15! Silberschatz, Galvin and Gagne 2005!
16 Deadlock Prevention! Restrain the ways request can be made. Mutual Exclusion not required for sharable resources; must hold for nonsharable resources. Hold and Wait must guarantee that whenever a process requests a resource, it does not hold any other resources. Require process to request and be allocated all its resources before it begins execution, or allow process to request resources only when the process has none. Low resource utilization; starvation possible. 7.16! Silberschatz, Galvin and Gagne 2005!
17 Deadlock Prevention (Cont.)! No Preemption If a process that is holding some resources requests another resource that cannot be immediately allocated to it, then all resources currently being held are released. Preempted resources are added to the list of resources for which the process is waiting. Process will be restarted only when it can regain its old resources, as well as the new ones that it is requesting. Circular Wait impose a total ordering of all resource types, and require that each process requests resources in an increasing order of enumeration. 7.17! Silberschatz, Galvin and Gagne 2005!
18 Deadlock Avoidance! Requires that the system has some additional a priori information available. Simplest and most useful model requires that each process declare the maximum number of resources of each type that it may need. The deadlock-avoidance algorithm dynamically examines the resource-allocation state to ensure that there can never be a circular-wait condition. Resource-allocation state is defined by the number of available and allocated resources, and the maximum demands of the processes. 7.18! Silberschatz, Galvin and Gagne 2005!
19 Deadlock Detection! Allow system to enter deadlock state Detection algorithm Recovery scheme 7.19! Silberschatz, Galvin and Gagne 2005!
20 Safe State! When a process requests an available resource, system must decide if immediate allocation leaves the system in a safe state. System is in safe state if there exists a safe sequence of all processes. Sequence <P 1, P 2,, P n > is safe if for each P i, the resources that P i can still request can be satisfied by currently available resources + resources held by all the P j, with j<i. If P i resource needs are not immediately available, then P i can wait until all P j have finished. When P j is finished, P i can obtain needed resources, execute, return allocated resources, and terminate. When P i terminates, P i+1 can obtain its needed resources, and so on. 7.20! Silberschatz, Galvin and Gagne 2005!
21 Basic Facts! If a system is in safe state no deadlocks. If a system is in unsafe state possibility of deadlock. Avoidance ensure that a system will never enter an unsafe state. 7.21! Silberschatz, Galvin and Gagne 2005!
22 Safe, Unsafe, Deadlock State! 7.22! Silberschatz, Galvin and Gagne 2005!
23 Resource-Allocation Graph Algorithm! Claim edge P i R j indicated that process P j may request resource R j ; represented by a dashed line. Claim edge converts to request edge when a process requests a resource. When a resource is released by a process, assignment edge reconverts to a claim edge. Resources must be claimed a priori in the system. 7.23! Silberschatz, Galvin and Gagne 2005!
24 Resource-Allocation Graph For Deadlock Avoidance! 7.24! Silberschatz, Galvin and Gagne 2005!
25 Unsafe State In Resource-Allocation Graph! 7.25! Silberschatz, Galvin and Gagne 2005!
26 Example formal algorithms! Banker s Algorithm Resource-Request Algorithm Safety Algorithm 7.26! Silberschatz, Galvin and Gagne 2005!
27 Stop Here! 7.27! Silberschatz, Galvin and Gagne 2005!
28 Banker s Algorithm! Multiple instances. Each process must a priori claim maximum use. When a process requests a resource it may have to wait. When a process gets all its resources it must return them in a finite amount of time. 7.28! Silberschatz, Galvin and Gagne 2005!
29 Data Structures for the Banker s Algorithm! Let n = number of processes, and m = number of resources types. Available: Vector of length m. If available [j] = k, there are k instances of resource type R j available. Max: n x m matrix. If Max [i,j] = k, then process P i may request at most k instances of resource type R j. Allocation: n x m matrix. If Allocation[i,j] = k then P i is currently allocated k instances of R j. Need: n x m matrix. If Need[i,j] = k, then P i may need k more instances of R j to complete its task. Need [i,j] = Max[i,j] Allocation [i,j]. 7.29! Silberschatz, Galvin and Gagne 2005!
30 Safety Algorithm! 1. Let Work and Finish be vectors of length m and n, respectively. Initialize: Work = Available! Finish [i] = false for i - 1,3,, n. 2. Find and i such that both: (a) Finish [i] = false (b) Need i Work! If no such i exists, go to step Work = Work + Allocation i Finish[i] = true go to step If Finish [i] == true for all i, then the system is in a safe state. 7.30! Silberschatz, Galvin and Gagne 2005!
31 Resource-Request Algorithm for Process P i! Request = request vector for process P i. If Request i [j] = k then process P i wants k instances of resource type R j. 1. If Request i Need i go to step 2. Otherwise, raise error condition, since process has exceeded its maximum claim. 2. If Request i Available, go to step 3. Otherwise P i must wait, since resources are not available. 3. Pretend to allocate requested resources to P i by modifying the state as follows: Available = Available = Request i ;! Allocation i = Allocation i + Request i ; Need i = Need i Request i ;! If safe the resources are allocated to Pi.! If unsafe Pi must wait, and the old resource-allocation state is restored! 7.31! Silberschatz, Galvin and Gagne 2005!
32 Example of Banker s Algorithm! 5 processes P 0 through P 4 ; 3 resource types A (10 instances), B (5instances, and C (7 instances). Snapshot at time T 0 : Allocation!Max!Available!!!!A B C!A B C!A B C! P P P P P ! Silberschatz, Galvin and Gagne 2005!
33 Example (Cont.)! The content of the matrix. Need is defined to be Max Allocation. Need A B C! P P P P P The system is in a safe state since the sequence < P 1, P 3, P 4, P 2, P 0 > satisfies safety criteria. 7.33! Silberschatz, Galvin and Gagne 2005!
34 Example P 1 Request (1,0,2) (Cont.)! Check that Request Available (that is, (1,0,2) (3,3,2) true.!!!!allocation!need!available!!!!a B C!A B C!A B C! P P P P P Executing safety algorithm shows that sequence <P1, P3, P4, P0, P2> satisfies safety requirement. Can request for (3,3,0) by P4 be granted? Can request for (0,2,0) by P0 be granted? 7.34! Silberschatz, Galvin and Gagne 2005!
35 Deadlock Detection! Allow system to enter deadlock state Detection algorithm Recovery scheme 7.35! Silberschatz, Galvin and Gagne 2005!
36 Single Instance of Each Resource Type! Maintain wait-for graph Nodes are processes. P i P j if P i is waiting for P j.! Periodically invoke an algorithm that searches for a cycle in the graph. An algorithm to detect a cycle in a graph requires an order of n 2 operations, where n is the number of vertices in the graph. 7.36! Silberschatz, Galvin and Gagne 2005!
37 Resource-Allocation Graph and Wait-for Graph! Resource-Allocation Graph Corresponding wait-for graph 7.37! Silberschatz, Galvin and Gagne 2005!
38 Several Instances of a Resource Type! Available: A vector of length m indicates the number of available resources of each type. Allocation: An n x m matrix defines the number of resources of each type currently allocated to each process. Request: An n x m matrix indicates the current request of each process. If Request [i j ] = k, then process P i is requesting k more instances of resource type. R j. 7.38! Silberschatz, Galvin and Gagne 2005!
39 Detection Algorithm! 1. Let Work and Finish be vectors of length m and n, respectively Initialize: (a) Work = Available (b) For i = 1,2,, n, if Allocation i 0, then Finish[i] = false;otherwise, Finish[i] = true. 2. Find an index i such that both: (a) Finish[i] == false (b) Request i Work If no such i exists, go to step ! Silberschatz, Galvin and Gagne 2005!
40 Detection Algorithm (Cont.)! 3. Work = Work + Allocation i Finish[i] = true go to step If Finish[i] == false, for some i, 1 i n, then the system is in deadlock state. Moreover, if Finish[i] == false, then P i is deadlocked. Algorithm requires an order of O(m x n 2) operations to detect whether the system is in deadlocked state. 7.40! Silberschatz, Galvin and Gagne 2005!
41 Example of Detection Algorithm! Five processes P 0 through P 4 ; three resource types A (7 instances), B (2 instances), and C (6 instances). Snapshot at time T 0 : Allocation!Request!Available! A B C!A B C!A B C! P P P P P Sequence <P 0, P 2, P 3, P 1, P 4 > will result in Finish[i] = true for all i. 7.41! Silberschatz, Galvin and Gagne 2005!
42 Example (Cont.)! P 2 requests an additional instance of type C. Request!!!!A B C! P P P P P State of system? Can reclaim resources held by process P 0, but insufficient resources to fulfill other processes; requests. Deadlock exists, consisting of processes P 1, P 2, P 3, and P ! Silberschatz, Galvin and Gagne 2005!
43 Detection-Algorithm Usage! When, and how often, to invoke depends on: How often a deadlock is likely to occur? How many processes will need to be rolled back?! one for each disjoint cycle If detection algorithm is invoked arbitrarily, there may be many cycles in the resource graph and so we would not be able to tell which of the many deadlocked processes caused the deadlock. 7.43! Silberschatz, Galvin and Gagne 2005!
44 Recovery from Deadlock: Process Termination! Abort all deadlocked processes. Abort one process at a time until the deadlock cycle is eliminated. In which order should we choose to abort? Priority of the process. How long process has computed, and how much longer to completion. Resources the process has used. Resources process needs to complete. How many processes will need to be terminated. Is process interactive or batch? 7.44! Silberschatz, Galvin and Gagne 2005!
45 Recovery from Deadlock: Resource Preemption! Selecting a victim minimize cost. Rollback return to some safe state, restart process for that state. Starvation same process may always be picked as victim, include number of rollback in cost factor. 7.45! Silberschatz, Galvin and Gagne 2005!
46 The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. End of Chapter 7!
The Deadlock Problem. Deadlocks. Deadlocks. Bridge Crossing Example
The Deadlock Problem Deadlocks A set of blocked processes each holding a resource and waiting to acquire a resource held by another process in the set. Example System has 2 tape drives. P 1 and P 2 each
System model. Section 7.1. Operating Systems: Deadlock p. 1/15
System model Section 7.1 Resources: CPU, memory, files, devices, semaphores, etc. divided into several types each type has one or more identical instances Processes: 1. Request resource. (If resource cannot
Resource Allocation and Deadlock Resource Allocation and Handling
Resource Allocation and Deadlock Resource Allocation and Deadlock Handling Conditions for Deadlock [Coffman-etal 1971] 4 conditions must hold simultaneously for a deadlock to occur: Mutual exclusion: only
OPERATING SYSTEMS DEADLOCKS
OPERATING SYSTEMS DEADLOCKS Jerry Breecher 7: Deadlocks OPERATING SYSTEM Deadlocks What is a deadlock? What Is In This Chapter? Staying Safe: Preventing and Avoiding Deadlocks Living Dangerously: Let the
Shrimad Rajchandra Institute of Management & Computer Application
IntegratedMCA-3 rd Semester Course: 060060304-Fundamentals of Operating System LESSON PLAN Objective: To provide a comprehensive knowledge of Operating System and its services. Course Outcomes: Upon the
Chapter 15: Recovery System
Chapter 15: Recovery System Failure Classification Storage Structure Recovery and Atomicity Log-Based Recovery Shadow Paging Recovery With Concurrent Transactions Buffer Management Failure with Loss of
Operating Systems OBJECTIVES 7.1 DEFINITION. Chapter 7. Note:
Chapter 7 OBJECTIVES Operating Systems Define the purpose and functions of an operating system. Understand the components of an operating system. Understand the concept of virtual memory. Understand the
Devices and Device Controllers
I/O 1 Devices and Device Controllers network interface graphics adapter secondary storage (disks, tape) and storage controllers serial (e.g., mouse, keyboard) sound co-processors... I/O 2 Bus Architecture
Distributed Databases
C H A P T E R19 Distributed Databases Practice Exercises 19.1 How might a distributed database designed for a local-area network differ from one designed for a wide-area network? Data transfer on a local-area
Chapter 14: Recovery System
Chapter 14: Recovery System Chapter 14: Recovery System Failure Classification Storage Structure Recovery and Atomicity Log-Based Recovery Remote Backup Systems Failure Classification Transaction failure
Concepts of Database Management Seventh Edition. Chapter 7 DBMS Functions
Concepts of Database Management Seventh Edition Chapter 7 DBMS Functions Objectives Introduce the functions, or services, provided by a DBMS Describe how a DBMS handles updating and retrieving data Examine
Textbook and References
Transactions Qin Xu 4-323A Life Science Building, Shanghai Jiao Tong University Email: xuqin523@sjtu.edu.cn Tel: 34204573(O) Webpage: http://cbb.sjtu.edu.cn/~qinxu/ Webpage for DBMS Textbook and References
Lecture 7: Concurrency control. Rasmus Pagh
Lecture 7: Concurrency control Rasmus Pagh 1 Today s lecture Concurrency control basics Conflicts and serializability Locking Isolation levels in SQL Optimistic concurrency control Transaction tuning Transaction
CPU Scheduling. Basic Concepts. Basic Concepts (2) Basic Concepts Scheduling Criteria Scheduling Algorithms Batch systems Interactive systems
Basic Concepts Scheduling Criteria Scheduling Algorithms Batch systems Interactive systems Based on original slides by Silberschatz, Galvin and Gagne 1 Basic Concepts CPU I/O Burst Cycle Process execution
CS420: Operating Systems OS Services & System Calls
NK YORK COLLEGE OF PENNSYLVANIA HG OK 2 YORK COLLEGE OF PENNSYLVAN OS Services & System Calls James Moscola Department of Physical Sciences York College of Pennsylvania Based on Operating System Concepts,
Far-western University Central Office, Mahendranagar Operating System
Far-western University Central Office, Mahendranagar Operating System Course Title: Operating Systems Credit: 3+1 Course No: B.Sc. CS OS 231 hour 45+15 Nature of the Course: Theory + Lab Year: 2 nd, Semester:
OS OBJECTIVE QUESTIONS
OS OBJECTIVE QUESTIONS Which one of the following is Little s formula Where n is the average queue length, W is the time that a process waits 1)n=Lambda*W 2)n=Lambda/W 3)n=Lambda^W 4)n=Lambda*(W-n) Answer:1
Objectives. Chapter 5: Process Scheduling. Chapter 5: Process Scheduling. 5.1 Basic Concepts. To introduce CPU scheduling
Objectives To introduce CPU scheduling To describe various CPU-scheduling algorithms Chapter 5: Process Scheduling To discuss evaluation criteria for selecting the CPUscheduling algorithm for a particular
2 nd Semester 2008/2009
Chapter 17: System Departamento de Engenharia Informática Instituto Superior Técnico 2 nd Semester 2008/2009 Slides baseados nos slides oficiais do livro Database System c Silberschatz, Korth and Sudarshan.
Chapter 12 File Management. Roadmap
Operating Systems: Internals and Design Principles, 6/E William Stallings Chapter 12 File Management Dave Bremer Otago Polytechnic, N.Z. 2008, Prentice Hall Overview Roadmap File organisation and Access
Chapter 12 File Management
Operating Systems: Internals and Design Principles, 6/E William Stallings Chapter 12 File Management Dave Bremer Otago Polytechnic, N.Z. 2008, Prentice Hall Roadmap Overview File organisation and Access
Operating System: Scheduling
Process Management Operating System: Scheduling OS maintains a data structure for each process called Process Control Block (PCB) Information associated with each PCB: Process state: e.g. ready, or waiting
Objectives. Chapter 5: CPU Scheduling. CPU Scheduler. Non-preemptive and preemptive. Dispatcher. Alternating Sequence of CPU And I/O Bursts
Objectives Chapter 5: CPU Scheduling Introduce CPU scheduling, which is the basis for multiprogrammed operating systems Describe various CPU-scheduling algorithms Discuss evaluation criteria for selecting
Transactions. SET08104 Database Systems. Copyright @ Napier University
Transactions SET08104 Database Systems Copyright @ Napier University Concurrency using Transactions The goal in a concurrent DBMS is to allow multiple users to access the database simultaneously without
Recovery System C H A P T E R16. Practice Exercises
C H A P T E R16 Recovery System Practice Exercises 16.1 Explain why log records for transactions on the undo-list must be processed in reverse order, whereas redo is performed in a forward direction. Answer:
Outline. Failure Types
Outline Database Management and Tuning Johann Gamper Free University of Bozen-Bolzano Faculty of Computer Science IDSE Unit 11 1 2 Conclusion Acknowledgements: The slides are provided by Nikolaus Augsten
An Overview of Distributed Databases
International Journal of Information and Computation Technology. ISSN 0974-2239 Volume 4, Number 2 (2014), pp. 207-214 International Research Publications House http://www. irphouse.com /ijict.htm An Overview
CS4410 - Fall 2008 Homework 2 Solution Due September 23, 11:59PM
CS4410 - Fall 2008 Homework 2 Solution Due September 23, 11:59PM Q1. Explain what goes wrong in the following version of Dekker s Algorithm: CSEnter(int i) inside[i] = true; while(inside[j]) inside[i]
Chapter 16: Recovery System
Chapter 16: Recovery System Failure Classification Failure Classification Transaction failure : Logical errors: transaction cannot complete due to some internal error condition System errors: the database
In This Lecture. More Concurrency. Deadlocks. Precedence/Wait-For Graphs. Example. Example
In This Lecture More Concurrency Database Systems Lecture 17 Natasha Alechina Deadlock detection Deadlock prevention Timestamping For more information Connolly and Begg chapter 0 Deadlocks Precedence/ait-For
Unit 12 Database Recovery
Unit 12 Database Recovery 12-1 Contents 12.1 Introduction 12.2 Transactions 12.3 Transaction Failures and Recovery 12.4 System Failures and Recovery 12.5 Media Failures and Recovery Wei-Pang Yang, Information
Computer Science 4302 Operating Systems. Student Learning Outcomes
Computer Science 4302 Operating Systems Student Learning Outcomes 1. The student will learn what operating systems are, what they do, and how they are designed and constructed. The student will be introduced
Chapter 11 I/O Management and Disk Scheduling
Operating Systems: Internals and Design Principles, 6/E William Stallings Chapter 11 I/O Management and Disk Scheduling Dave Bremer Otago Polytechnic, NZ 2008, Prentice Hall I/O Devices Roadmap Organization
W4118 Operating Systems. Instructor: Junfeng Yang
W4118 Operating Systems Instructor: Junfeng Yang Outline Introduction to scheduling Scheduling algorithms 1 Direction within course Until now: interrupts, processes, threads, synchronization Mostly mechanisms
! Volatile storage: ! Nonvolatile storage:
Chapter 17: Recovery System Failure Classification! Failure Classification! Storage Structure! Recovery and Atomicity! Log-Based Recovery! Shadow Paging! Recovery With Concurrent Transactions! Buffer Management!
Comp 204: Computer Systems and Their Implementation. Lecture 12: Scheduling Algorithms cont d
Comp 204: Computer Systems and Their Implementation Lecture 12: Scheduling Algorithms cont d 1 Today Scheduling continued Multilevel queues Examples Thread scheduling 2 Question A starvation-free job-scheduling
Scheduling. Yücel Saygın. These slides are based on your text book and on the slides prepared by Andrew S. Tanenbaum
Scheduling Yücel Saygın These slides are based on your text book and on the slides prepared by Andrew S. Tanenbaum 1 Scheduling Introduction to Scheduling (1) Bursts of CPU usage alternate with periods
Deciding which process to run. (Deciding which thread to run) Deciding how long the chosen process can run
SFWR ENG 3BB4 Software Design 3 Concurrent System Design 2 SFWR ENG 3BB4 Software Design 3 Concurrent System Design 11.8 10 CPU Scheduling Chapter 11 CPU Scheduling Policies Deciding which process to run
Chapter 14: Distributed Operating Systems
Chapter 14: Distributed Operating Systems Chapter 14: Distributed Operating Systems Motivation Types of Distributed Operating Systems Network Structure Network Topology Communication Structure Communication
Chapter 14: Protection. Chapter 14: Protection. Objectives. Goals of Protection. Domain Structure. Principles of Protection
Chapter 14: Protection Chapter 14: Protection Goals of Protection Principles of Protection Domain of Protection Access Matrix Implementation of Access Matrix Access Control Revocation of Access Rights
Scheduling Sporadic Tasks with Shared Resources in Hard-Real-Time Systems
Scheduling Sporadic Tasks with Shared Resources in Hard-Real- Systems Kevin Jeffay * University of North Carolina at Chapel Hill Department of Computer Science Chapel Hill, NC 27599-3175 jeffay@cs.unc.edu
Chapter 1 8 Essay Question Review
Chapter 1 8 Essay Question Review 1. Explain why an operating system can be viewed as a resource allocator. Ans: A computer system has many resources that may be required to solve a problem: CPU time,
Oracle Architecture. Overview
Oracle Architecture Overview The Oracle Server Oracle ser ver Instance Architecture Instance SGA Shared pool Database Cache Redo Log Library Cache Data Dictionary Cache DBWR LGWR SMON PMON ARCn RECO CKPT
Introduction. What is an Operating System?
Introduction What is an Operating System? 1 What is an Operating System? 2 Why is an Operating System Needed? 3 How Did They Develop? Historical Approach Affect of Architecture 4 Efficient Utilization
Chapter 16: Distributed Operating Systems
Module 16: Distributed ib System Structure, Silberschatz, Galvin and Gagne 2009 Chapter 16: Distributed Operating Systems Motivation Types of Network-Based Operating Systems Network Structure Network Topology
(Pessimistic) Timestamp Ordering. Rules for read and write Operations. Pessimistic Timestamp Ordering. Write Operations and Timestamps
(Pessimistic) stamp Ordering Another approach to concurrency control: Assign a timestamp ts(t) to transaction T at the moment it starts Using Lamport's timestamps: total order is given. In distributed
DB2 Backup and Recovery
Information Management Technology Ecosystem DB2 Backup and Recovery Information Management Agenda Why back up data Basic backup and recovery concept Logging Log file states Logging types Infinite logging
Redo Recovery after System Crashes
Redo Recovery after System Crashes David Lomet Microsoft Corporation One Microsoft Way Redmond, WA 98052 lomet@microsoft.com Mark R. Tuttle Digital Equipment Corporation One Kendall Square Cambridge, MA
Chapter 12 File Management
Operating Systems: Internals and Design Principles, 6/E William Stallings Chapter 12 File Management Patricia Roy Manatee Community College, Venice, FL 2008, Prentice Hall File Management File management
How To Understand The History Of An Operating System
7 Operating Systems 7.1 Source: Foundations of Computer Science Cengage Learning Objectives After studying this chapter, the student should be able to: 7.2 Understand the role of the operating system.
Fair Scheduler. Table of contents
Table of contents 1 Purpose... 2 2 Introduction... 2 3 Installation... 3 4 Configuration...3 4.1 Scheduler Parameters in mapred-site.xml...4 4.2 Allocation File (fair-scheduler.xml)... 6 4.3 Access Control
Announcements. Basic Concepts. Histogram of Typical CPU- Burst Times. Dispatcher. CPU Scheduler. Burst Cycle. Reading
Announcements Reading Chapter 5 Chapter 7 (Monday or Wednesday) Basic Concepts CPU I/O burst cycle Process execution consists of a cycle of CPU execution and I/O wait. CPU burst distribution What are the
Operating Systems Concepts: Chapter 7: Scheduling Strategies
Operating Systems Concepts: Chapter 7: Scheduling Strategies Olav Beckmann Huxley 449 http://www.doc.ic.ac.uk/~ob3 Acknowledgements: There are lots. See end of Chapter 1. Home Page for the course: http://www.doc.ic.ac.uk/~ob3/teaching/operatingsystemsconcepts/
CPU Scheduling. CPU Scheduling
CPU Scheduling Electrical and Computer Engineering Stephen Kim (dskim@iupui.edu) ECE/IUPUI RTOS & APPS 1 CPU Scheduling Basic Concepts Scheduling Criteria Scheduling Algorithms Multiple-Processor Scheduling
4003-440/4003-713 Operating Systems I. Process Scheduling. Warren R. Carithers (wrc@cs.rit.edu) Rob Duncan (rwd@cs.rit.edu)
4003-440/4003-713 Operating Systems I Process Scheduling Warren R. Carithers (wrc@cs.rit.edu) Rob Duncan (rwd@cs.rit.edu) Review: Scheduling Policy Ideally, a scheduling policy should: Be: fair, predictable
OPERATING SYSTEMS SCHEDULING
OPERATING SYSTEMS SCHEDULING Jerry Breecher 5: CPU- 1 CPU What Is In This Chapter? This chapter is about how to get a process attached to a processor. It centers around efficient algorithms that perform
Chapter 5: CPU Scheduling. Operating System Concepts 8 th Edition
Chapter 5: CPU Scheduling Silberschatz, Galvin and Gagne 2009 Chapter 5: CPU Scheduling Basic Concepts Scheduling Criteria Scheduling Algorithms Thread Scheduling Multiple-Processor Scheduling Operating
Why Threads Are A Bad Idea (for most purposes)
Why Threads Are A Bad Idea (for most purposes) John Ousterhout Sun Microsystems Laboratories john.ousterhout@eng.sun.com http://www.sunlabs.com/~ouster Introduction Threads: Grew up in OS world (processes).
Acronis Backup & Recovery: Events in Application Event Log of Windows http://kb.acronis.com/content/38327
Acronis Backup & Recovery: Events in Application Event Log of Windows http://kb.acronis.com/content/38327 Mod ule_i D Error _Cod e Error Description 1 1 PROCESSOR_NULLREF_ERROR 1 100 ERROR_PARSE_PAIR Failed
Information Systems. Computer Science Department ETH Zurich Spring 2012
Information Systems Computer Science Department ETH Zurich Spring 2012 Lecture VI: Transaction Management (Recovery Manager) Recovery Manager ETH Zurich, Spring 2012 Information Systems 3 Failure Recovery
5 INTEGER LINEAR PROGRAMMING (ILP) E. Amaldi Fondamenti di R.O. Politecnico di Milano 1
5 INTEGER LINEAR PROGRAMMING (ILP) E. Amaldi Fondamenti di R.O. Politecnico di Milano 1 General Integer Linear Program: (ILP) min c T x Ax b x 0 integer Assumption: A, b integer The integrality condition
Two Parts. Filesystem Interface. Filesystem design. Interface the user sees. Implementing the interface
File Management Two Parts Filesystem Interface Interface the user sees Organization of the files as seen by the user Operations defined on files Properties that can be read/modified Filesystem design Implementing
How To Recover From Failure In A Relational Database System
Chapter 17: Recovery System Database System Concepts See www.db-book.com for conditions on re-use Chapter 17: Recovery System Failure Classification Storage Structure Recovery and Atomicity Log-Based Recovery
Chapter 11: File System Implementation. Operating System Concepts with Java 8 th Edition
Chapter 11: File System Implementation 11.1 Silberschatz, Galvin and Gagne 2009 Chapter 11: File System Implementation File-System Structure File-System Implementation Directory Implementation Allocation
Overview of Presentation. (Greek to English dictionary) Different systems have different goals. What should CPU scheduling optimize?
Overview of Presentation (Greek to English dictionary) introduction to : elements, purpose, goals, metrics lambda request arrival rate (e.g. 200/second) non-preemptive first-come-first-served, shortest-job-next
Data Recovery and High Availability Guide and Reference
IBM DB2 Universal Database Data Recovery and High Availability Guide and Reference Version 8 SC09-4831-00 IBM DB2 Universal Database Data Recovery and High Availability Guide and Reference Version 8 SC09-4831-00
Maintaining a Microsoft Windows Server 2003 Environment
Maintaining a Microsoft Windows Server 2003 Environment Course number: 2275C Course lenght: 3 days Course Outline Module 1: Preparing to Administer a Server This module explains how to administer a server.
Scheduling Shop Scheduling. Tim Nieberg
Scheduling Shop Scheduling Tim Nieberg Shop models: General Introduction Remark: Consider non preemptive problems with regular objectives Notation Shop Problems: m machines, n jobs 1,..., n operations
Chapter 10: Distributed DBMS Reliability
Chapter 10: Distributed DBMS Reliability Definitions and Basic Concepts Local Recovery Management In-place update, out-of-place update Distributed Reliability Protocols Two phase commit protocol Three
The Trip Scheduling Problem
The Trip Scheduling Problem Claudia Archetti Department of Quantitative Methods, University of Brescia Contrada Santa Chiara 50, 25122 Brescia, Italy Martin Savelsbergh School of Industrial and Systems
The Oracle Universal Server Buffer Manager
The Oracle Universal Server Buffer Manager W. Bridge, A. Joshi, M. Keihl, T. Lahiri, J. Loaiza, N. Macnaughton Oracle Corporation, 500 Oracle Parkway, Box 4OP13, Redwood Shores, CA 94065 { wbridge, ajoshi,
Operating Systems 4 th Class
Operating Systems 4 th Class Lecture 1 Operating Systems Operating systems are essential part of any computer system. Therefore, a course in operating systems is an essential part of any computer science
Operating Systems, 6 th ed. Test Bank Chapter 7
True / False Questions: Chapter 7 Memory Management 1. T / F In a multiprogramming system, main memory is divided into multiple sections: one for the operating system (resident monitor, kernel) and one
Network Attached Storage. Jinfeng Yang Oct/19/2015
Network Attached Storage Jinfeng Yang Oct/19/2015 Outline Part A 1. What is the Network Attached Storage (NAS)? 2. What are the applications of NAS? 3. The benefits of NAS. 4. NAS s performance (Reliability
Review: The ACID properties
Recovery Review: The ACID properties A tomicity: All actions in the Xaction happen, or none happen. C onsistency: If each Xaction is consistent, and the DB starts consistent, it ends up consistent. I solation:
High-Performance Concurrency Control Mechanisms for Main-Memory Databases
High-Performance Concurrency Control Mechanisms for Main-Memory Databases Per-Åke Larson 1, Spyros Blanas 2, Cristian Diaconu 1, Craig Freedman 1, Jignesh M. Patel 2, Mike Zwilling 1 Microsoft 1, University
CIS 700: algorithms for Big Data
CIS 700: algorithms for Big Data Lecture 6: Graph Sketching Slides at http://grigory.us/big-data-class.html Grigory Yaroslavtsev http://grigory.us Sketching Graphs? We know how to sketch vectors: v Mv
Contributions to Gang Scheduling
CHAPTER 7 Contributions to Gang Scheduling In this Chapter, we present two techniques to improve Gang Scheduling policies by adopting the ideas of this Thesis. The first one, Performance- Driven Gang Scheduling,
CPU SCHEDULING (CONT D) NESTED SCHEDULING FUNCTIONS
CPU SCHEDULING CPU SCHEDULING (CONT D) Aims to assign processes to be executed by the CPU in a way that meets system objectives such as response time, throughput, and processor efficiency Broken down into
PostgreSQL Concurrency Issues
PostgreSQL Concurrency Issues 1 PostgreSQL Concurrency Issues Tom Lane Red Hat Database Group Red Hat, Inc. PostgreSQL Concurrency Issues 2 Introduction What I want to tell you about today: How PostgreSQL
File Management. Chapter 12
File Management Chapter 12 File Management File management system is considered part of the operating system Input to applications is by means of a file Output is saved in a file for long-term storage
Chapter 11: File System Implementation. Chapter 11: File System Implementation. Objectives. File-System Structure
Chapter 11: File System Implementation Chapter 11: File System Implementation File-System Structure File-System Implementation Directory Implementation Allocation Methods Free-Space Management Efficiency
Job Scheduling for MapReduce
UC Berkeley Job Scheduling for MapReduce Matei Zaharia, Dhruba Borthakur *, Joydeep Sen Sarma *, Scott Shenker, Ion Stoica RAD Lab, * Facebook Inc 1 Motivation Hadoop was designed for large batch jobs
Introduction to Distributed Systems
Introduction to Distributed Systems CSE 380 Computer Operating Systems Instructor: Insup Lee University of Pennsylvania Fall 2003 Lecture Note: Distributed Systems Why do we develop distributed systems?
Approximation Algorithms
Approximation Algorithms or: How I Learned to Stop Worrying and Deal with NP-Completeness Ong Jit Sheng, Jonathan (A0073924B) March, 2012 Overview Key Results (I) General techniques: Greedy algorithms
SAN Conceptual and Design Basics
TECHNICAL NOTE VMware Infrastructure 3 SAN Conceptual and Design Basics VMware ESX Server can be used in conjunction with a SAN (storage area network), a specialized high speed network that connects computer
Common Approaches to Real-Time Scheduling
Common Approaches to Real-Time Scheduling Clock-driven time-driven schedulers Priority-driven schedulers Examples of priority driven schedulers Effective timing constraints The Earliest-Deadline-First
CSE 326, Data Structures. Sample Final Exam. Problem Max Points Score 1 14 (2x7) 2 18 (3x6) 3 4 4 7 5 9 6 16 7 8 8 4 9 8 10 4 Total 92.
Name: Email ID: CSE 326, Data Structures Section: Sample Final Exam Instructions: The exam is closed book, closed notes. Unless otherwise stated, N denotes the number of elements in the data structure
The ConTract Model. Helmut Wächter, Andreas Reuter. November 9, 1999
The ConTract Model Helmut Wächter, Andreas Reuter November 9, 1999 Overview In Ahmed K. Elmagarmid: Database Transaction Models for Advanced Applications First in Andreas Reuter: ConTracts: A Means for
Backup Strategies for Integrity Virtual Machines
Backup Strategies for Integrity Virtual Machines Introduction...2 Basic Aspects of Data Protection for Virtual Environments...2 Backup and Recovery from the VM Host System...3 Backup and Recovery of Individual
Sybase Adaptive Server Enterprise
technical white paper Sybase Adaptive Server Enterprise Data Transfer Utility www.sybase.com Contents 1. Executive Summary..........................................................................................................
The Complete Performance Solution for Microsoft SQL Server
The Complete Performance Solution for Microsoft SQL Server Powerful SSAS Performance Dashboard Innovative Workload and Bottleneck Profiling Capture of all Heavy MDX, XMLA and DMX Aggregation, Partition,
Convenience: An OS makes a computer more convenient to use. Efficiency: An OS allows the computer system resources to be used in an efficient manner.
Introduction to Operating System PCSC-301 (For UG students) (Class notes and reference books are required to complete this study) Release Date: 27.12.2014 Operating System Objectives and Functions An OS
Lecture Outline Overview of real-time scheduling algorithms Outline relative strengths, weaknesses
Overview of Real-Time Scheduling Embedded Real-Time Software Lecture 3 Lecture Outline Overview of real-time scheduling algorithms Clock-driven Weighted round-robin Priority-driven Dynamic vs. static Deadline
Objectives. Distributed Databases and Client/Server Architecture. Distributed Database. Data Fragmentation
Objectives Distributed Databases and Client/Server Architecture IT354 @ Peter Lo 2005 1 Understand the advantages and disadvantages of distributed databases Know the design issues involved in distributed
Design of LDPC codes
Design of LDPC codes Codes from finite geometries Random codes: Determine the connections of the bipartite Tanner graph by using a (pseudo)random algorithm observing the degree distribution of the code
Backup and Recovery...
7 Backup and Recovery... Fourteen percent (14%) of the DB2 UDB V8.1 for Linux, UNIX, and Windows Database Administration certification exam (Exam 701) and seventeen percent (17%) of the DB2 UDB V8.1 for
Operating Systems. III. Scheduling. http://soc.eurecom.fr/os/
Operating Systems Institut Mines-Telecom III. Scheduling Ludovic Apvrille ludovic.apvrille@telecom-paristech.fr Eurecom, office 470 http://soc.eurecom.fr/os/ Outline Basics of Scheduling Definitions Switching
Have both hardware and software. Want to hide the details from the programmer (user).
Input/Output Devices Chapter 5 of Tanenbaum. Have both hardware and software. Want to hide the details from the programmer (user). Ideally have the same interface to all devices (device independence).