현재이이미지를표시할수없습니다. Chapter 9: Virtual Memory
|
|
- Ashley Park
- 5 years ago
- Views:
Transcription
1 현재이이미지를표시할수없습니다. Chapter 9: Virtual Memory
2 Objectives To describe the benefits of a virtual memory system To explain the concepts of demand paging, page-replacement algorithms, and allocation of page frames To discuss the principle of the working-set model 9.2 Silberschatz, Galvin and Gagne 2009
3 Evolution of Memory System 9.3 Silberschatz, Galvin and Gagne 2009
4 Background : Virtual Memory Virtual memory The separation of user logical memory from physical memory. There is no static 1:1 match between physical memory address vs. logical memory address. Then, how can we find proper memory location? Page Table! Through the page table, each logical address can be mapped into different physical address Only some parts of the program are needed to be in memory for execution. Logical address space can therefore be much larger than physical address space. Helps to allows address spaces to be shared by several processes. E.g., page sharing or segment sharing 9.4 Silberschatz, Galvin and Gagne 2009
5 Background : Virtual Memory Virtual memory can be implemented via: Demand paging Demand segmentation 9.5 Silberschatz, Galvin and Gagne 2009
6 Virtual Address Space Virtual address space of process refers to logical view of how process is stored in memory. A process is assumed to address between 0 to MAX A (logical) process begins at a certain logical address, say address 0, and exists in continuous memory. The space between stack and heap is a part of a virtual address space, but it will only require actual physical pages only if stack or heap grows. 9.6 Silberschatz, Galvin and Gagne 2009
7 Virtual Memory that is Larger than Physical Memory Continuou s address non-continuous address Some parts are resided in disk 9.7 Silberschatz, Galvin and Gagne 2009
8 Virtual Memory that is Larger than Physical Memory 9.8 Silberschatz, Galvin and Gagne 2009
9 Need for Block Mapping 9.9 Silberschatz, Galvin and Gagne 2009
10 Demand Paging Page is needed Page is referenced by a process In-memory but invalid reference abort Due to page replacement, page protection (such as readonly), etc. Not-in-memory bring to memory (miss penalty) Demanding paging Similar to paging system with swapping where processes can reside in secondary storage (usually disk). Swap partition can be treated as the extension of main memory. Can be non continuous in physical memory AND can be resided in disk 9.10 Silberschatz, Galvin and Gagne 2009
11 Demand Paging Bring a page into memory only when it is needed Less I/O needed Less memory needed Faster response More users More concurrent programs 9.11 Silberschatz, Galvin and Gagne 2009
12 Swapper vs. Pager In virtual memory system, we usually use Lazy Swapper, which never swaps a page into memory unless that page will be needed. Swapper vs. Pager Swapper : Since we are now viewing a process as a sequence of pages, rather than as one continuous address space, swapper is technically incorrect. Swapper manipulates an entire process. Pager is concerned with the individual pages of a process. In virtual systems, we thus use pager, rather than swapper Silberschatz, Galvin and Gagne 2009
13 Transfer of a Paged Memory to Disk Space 9.13 Silberschatz, Galvin and Gagne 2009
14 Valid-Invalid Bit With each page table entry, a valid invalid bit is associated (1 in-memory, 0 not-in-memory) Initially, valid invalid bit is set to 0 on all entries Example of a page table snapshot: Frame # M page table valid-invalid bit During address translation, if valid invalid bit in page table entry is 0 page fault 9.14 Silberschatz, Galvin and Gagne 2009
15 Page Table When Some Pages Are Not in Main Memory In chapter 8, we use valid bit to decide whether the referenced address is legal process space or not. In virtual memory, valid bit is used to decide Valid=1; associated page is both legal and in memory. Valid=0; illegal or (legal but not in memory) page fault Silberschatz, Galvin and Gagne 2009
16 Page Table When Some Pages Are Not in Main Memory In virtual memory, the number of page table entries is just the number of required pages for each process. different page table length is possible (PTLR is required) c.f., in slide 8.58, In real memory, page table should cover all address space of main memory Silberschatz, Galvin and Gagne 2009
17 Implementation of Page Table Depending on the existence of PTLR If no existence There is no ways to distinguish that valid = 0 means Illegal address access or legal but not in memory Additional information bit is required. If existence There is no illegal access, so valid = 0 means that the page is not in memory Page Fault routine starts. Except the page table, Page Frame Table (i.e., Memory Table) is required, to trace whole memory usage. compare with slide Silberschatz, Galvin and Gagne 2009
18 Page Fault If there is ever a reference to a page, first reference will trap to OS Page Fault OS looks at another table field, such as protection bit or valid bit to decide: By protection bit, Invalid reference trap (i.e., address space violation or read/write violation) By valid bit, Not in memory page fault Get empty frame. Swap page into frame. Restart table access with validation bit = Silberschatz, Galvin and Gagne 2009
19 Steps in Handling a Page Fault 9.19 Silberschatz, Galvin and Gagne 2009
20 What happens if there is no free frame? Page replacement find some pages in memory, but not really in use, swap it out Which Algorithm? Performance want an algorithm which will result in minimum number of page faults Same page may be brought into memory several times 9.20 Silberschatz, Galvin and Gagne 2009
21 Performance of Demand Paging Page Fault Rate 0 p 1.0 if p = 0 no page faults if p = 1, every reference is a fault Effective Access Time (EAT) EAT = (1 p) x memory access + p x {(page fault overhead) + (swap page out) + (swap page in) + (restart overhead)} 9.21 Silberschatz, Galvin and Gagne 2009
22 Demand Paging Example Suppose Memory access time = 200 nanoseconds Average page-fault service time = 8 milliseconds EAT = (1 p) x (200 nanoseconds) + p x (8 milliseconds) = (1 p ) x p x 8,000,000 = p x 7,999,800 If one access out of 1,000 causes a page fault, x 7,999,800 = (i.e., EAT = 8.2 microseconds) This is a slowdown by a factor of about 40!! (why? 200 nano memory access time vs nano page fault service time) 9.22 Silberschatz, Galvin and Gagne 2009
23 Demand Paging Example So what? Page fault is a critical factor in virtual memory systems. So, we must reduce page faults In other words, we must use a good page replacement algorithm 9.23 Silberschatz, Galvin and Gagne 2009
24 Some Benefits of Virtual Memory Virtual memory allows other benefits during process creation: - Page Sharing - Copy-on-Write - Memory-Mapped Files (later, slide 9.66) 9.24 Silberschatz, Galvin and Gagne 2009
25 Page Sharing Shared Library Using Virtual Memory Virtual memory also allows files and memory to be shared by two or more processes through page sharing Silberschatz, Galvin and Gagne 2009
26 Copy-on-Write Copy-on-Write (COW) allows both parent and child processes to initially share the same pages in memory If either process modifies a shared page, only then the page is copied therefore, it is called as Copy-on-Write. COW allows more efficient process creation because only modified pages are copied (forked) Free pages are allocated from a pool of zeroed-out pages (i.e., no need to write back into disk) Silence replacement 9.26 Silberschatz, Galvin and Gagne 2009
27 Copy-on-Write Before process 1 modifies page C 9.27 Silberschatz, Galvin and Gagne 2009
28 Copy-on-Write After process 1 modifies page C 9.28 Silberschatz, Galvin and Gagne 2009
29 Page Replacement Need for Page Replacement Physical memory full how can we treat the page B and M? Memory full 9.29 Silberschatz, Galvin and Gagne 2009
CSE 4/521 Introduction to Operating Systems. Lecture 15 Virtual Memory I (Background, Demand Paging) Summer 2018
CSE 4/521 Introduction to Operating Systems Lecture 15 Virtual Memory I (Background, Demand Paging) Summer 2018 Overview Objective: To describe the benefits of a virtual memory system. To explain the concept
More informationChapter 8: Virtual Memory. Operating System Concepts Essentials 2 nd Edition
Chapter 8: Virtual Memory Silberschatz, Galvin and Gagne 2013 Chapter 8: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating
More informationChapter 9: Virtual-Memory Management. Operating System Concepts 8 th Edition,
Chapter 9: Virtual-Memory Management, Silberschatz, Galvin and Gagne 2009 Chapter 9: Virtual-Memory Management Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped
More informationChapter 9: Virtual Memory. Operating System Concepts 9 th Edition
Chapter 9: Virtual Memory Silberschatz, Galvin and Gagne 2013 Chapter 9: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating
More informationChapter 9: Virtual Memory
Chapter 9: Virtual Memory Silberschatz, Galvin and Gagne 2013 Chapter 9: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating
More informationChapter 9: Virtual-Memory
Chapter 9: Virtual-Memory Management Chapter 9: Virtual-Memory Management Background Demand Paging Page Replacement Allocation of Frames Thrashing Other Considerations Silberschatz, Galvin and Gagne 2013
More informationChapter 8: Virtual Memory. Operating System Concepts
Chapter 8: Virtual Memory Silberschatz, Galvin and Gagne 2009 Chapter 8: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating
More informationVirtual Memory Silberschatz: 9. Operating Systems. Autumn CS4023
Operating Systems Autumn 2017-2018 Outline 1 Virtual Memory Silberschatz: 9 Outline Virtual Memory Silberschatz: 9 1 Virtual Memory Silberschatz: 9 Dynamic Loading Virtual Memory Silberschatz: 9 Routine
More informationDemand Paging. Valid-Invalid Bit. Steps in Handling a Page Fault. Page Fault. Transfer of a Paged Memory to Contiguous Disk Space
Demand Paging Transfer of a Paged Memory to Contiguous Disk Space Bring a page into memory only when it is needed. Less I/O needed Less memory needed Faster response More users Page is needed reference
More informationChapter 9: Virtual Memory. Chapter 9: Virtual Memory. Objectives. Background. Virtual-address address Space
Chapter 9: Virtual Memory Chapter 9: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating Kernel Memory Other Considerations
More informationBackground. Demand Paging. valid-invalid bit. Tevfik Koşar. CSC Operating Systems Spring 2007
CSC 0 - Operating Systems Spring 007 Lecture - XIII Virtual Memory Tevfik Koşar Background Virtual memory separation of user logical memory from physical memory. Only part of the program needs to be in
More informationChapter 9: Virtual Memory
Chapter 9: Virtual Memory Chapter 9: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating Kernel Memory Other Considerations
More informationCS420: Operating Systems
Virtual Memory James Moscola Department of Physical Sciences York College of Pennsylvania Based on Operating System Concepts, 9th Edition by Silberschatz, Galvin, Gagne Background Code needs to be in memory
More informationVirtual Memory - I. Roadmap. Tevfik Koşar. CSE 421/521 - Operating Systems Fall Lecture - XV. University at Buffalo.
CSE /5 - Operating Systems Fall 0 Lecture - XV Virtual Memory - I Tevfik Koşar University at Buffalo October rd, 0 Roadmap Virtual Memory Demand Paging Page Faults Page Replacement Page Replacement Algorithms
More informationVirtual Memory - I. Roadmap. Background. Demand Paging. valid-invalid bit. Tevfik Koşar. CSE 421/521 - Operating Systems Fall 2012
CSE / - Operating Systems Fall Roadmap Lecture - XV Virtual Memory - I Virtual Memory Demand Paging Page Faults Page Replacement Page Replacement Algorithms FIFO Tevfik Koşar University at Buffalo October
More informationCS370 Operating Systems
CS370 Operating Systems Colorado State University Yashwant K Malaiya Spring 2018 L20 Virtual Memory Slides based on Text by Silberschatz, Galvin, Gagne Various sources 1 1 Questions from last time Page
More informationVirtual Memory Outline
Virtual Memory Outline Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating Kernel Memory Other Considerations Operating-System Examples
More informationRoadmap. Tevfik Ko!ar. CSC Operating Systems Spring Lecture - XIV Virtual Memory - I. Louisiana State University.
CSC 40 - Operating Systems Spring 008 Lecture - XIV Virtual Memory - I Tevfik Ko!ar Louisiana State University March th, 008 Roadmap Virtual Memory page replacement algorithms Background Virtual memory
More informationVirtual Memory. Virtual Memory. Demand Paging. valid-invalid bit. Virtual Memory Larger than Physical Memory
Virtual Memory Virtual Memory CSCI Operating Systems Design Department of Computer Science Virtual memory separation of user logical memory from physical memory. Only part of the program needs to be in
More informationChapter 10: Virtual Memory
Chapter 10: Virtual Memory Chapter 10: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating Kernel Memory Other Considerations
More informationChapter 3: Virtual Memory ว ตถ ประสงค. Background สามารถอธ บายข อด ในการท ระบบใช ว ธ การจ ดการหน วยความจ าแบบเสม อนได
Chapter 9: Virtual Memory Chapter 3: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating Kernel Memory Other Considerations
More informationVirtual Memory. CSCI 315 Operating Systems Design Department of Computer Science
Virtual Memory CSCI 315 Operating Systems Design Department of Computer Science Notice: The slides for this lecture were based on those Operating Systems Concepts, 9th ed., by Silberschatz, Galvin, and
More informationCSC Operating Systems Spring Lecture - XIV Virtual Memory - II. Tevfik Ko!ar. Louisiana State University. March 27 th, 2008.
CSC 0 - Operating Systems Spring 008 Lecture - XIV Virtual Memory - II Tevfik Ko!ar Louisiana State University March 7 th, 008 Background Virtual memory separation of user logical memory from physical
More informationOperating System Concepts 9 th Edition
Chapter 9: Virtual Memory Silberschatz, Galvin and Gagne 2013 Chapter 9: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating
More informationModule 9: Virtual Memory
Module 9: Virtual Memory Background Demand Paging Performance of Demand Paging Page Replacement Page-Replacement Algorithms Allocation of Frames Thrashing Other Considerations Demand Segmentation Operating
More informationChapter 9: Virtual Memory. Operating System Concepts 9 th Edition
Chapter 9: Virtual Memory Silberschatz, Galvin and Gagne 2013 Chapter 9: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating
More informationVirtual Memory. Overview: Virtual Memory. Virtual address space of a process. Virtual Memory. Demand Paging
TDDB68 Concurrent programming and operating systems Overview: Virtual Memory Virtual Memory [SGG7/8] Chapter 9 Background Demand Paging Page Replacement Allocation of Frames Thrashing and Data Access Locality
More informationOPERATING SYSTEM. Chapter 9: Virtual Memory
OPERATING SYSTEM Chapter 9: Virtual Memory Chapter 9: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating Kernel Memory
More informationChapter 9: Virtual Memory
Chapter 9: Virtual Memory Background Demand Paging Chapter 9: Virtual Memory Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating Kernel Memory Other Considerations
More informationCS370 Operating Systems
CS370 Operating Systems Colorado State University Yashwant K Malaiya Fall 2017 Lecture 21 Main Memory Slides based on Text by Silberschatz, Galvin, Gagne Various sources 1 1 FAQ Why not increase page size
More informationCS307: Operating Systems
CS307: Operating Systems Chentao Wu 吴晨涛 Associate Professor Dept. of Computer Science and Engineering Shanghai Jiao Tong University SEIEE Building 3-513 wuct@cs.sjtu.edu.cn Download Lectures ftp://public.sjtu.edu.cn
More informationMemory Management. Virtual Memory. By : Kaushik Vaghani. Prepared By : Kaushik Vaghani
Memory Management Virtual Memory By : Kaushik Vaghani Virtual Memory Background Page Fault Dirty Page / Dirty Bit Demand Paging Copy-on-Write Page Replacement Objectives To describe the benefits of a virtual
More informationVirtual Memory. Overview: Virtual Memory. Virtual address space of a process. Virtual Memory
TDIU Operating systems Overview: Virtual Memory Virtual Memory Background Demand Paging Page Replacement Allocation of Frames Thrashing and Data Access Locality [SGG7/8/9] Chapter 9 Copyright Notice: The
More informationChapters 9 & 10: Memory Management and Virtual Memory
Chapters 9 & 10: Memory Management and Virtual Memory Important concepts (for final, projects, papers) addressing: physical/absolute, logical/relative/virtual overlays swapping and paging memory protection
More informationChapter 9: Virtual Memory
Chapter 9: Virtual Memory Chapter 9: Virtual Memory 9.1 Background 9.2 Demand Paging 9.3 Copy-on-Write 9.4 Page Replacement 9.5 Allocation of Frames 9.6 Thrashing 9.7 Memory-Mapped Files 9.8 Allocating
More informationMulti-Process Systems: Memory (2) Memory & paging structures: free frames. Memory & paging structures. Physical memory
Multi-Process Systems: Memory (2) What we will learn A detailed description of various ways of organizing memory Discuss various memory-management techniques, including paging and segmentation To provide
More informationCSE325 Principles of Operating Systems. Virtual Memory. David P. Duggan. March 7, 2013
CSE325 Principles of Operating Systems Virtual Memory David P. Duggan dduggan@sandia.gov March 7, 2013 Reading Assignment 9 Chapters 10 & 11 File Systems, due 3/21 3/7/13 CSE325 - Virtual Memory 2 Outline
More informationCS370 Operating Systems
CS370 Operating Systems Colorado State University Yashwant K Malaiya Fall 2016 Lecture 32 Virtual Memory Slides based on Text by Silberschatz, Galvin, Gagne Various sources 1 1 Questions for you What is
More informationChapter 8: Main Memory. Operating System Concepts 8th Edition
Chapter 8: Main Memory Operating System Concepts 8th Edition Silberschatz, Galvin and Gagne 2009 Chapter 8: Memory Management Background Swapping Contiguous Memory Allocation Paging Structure of the Page
More informationVirtual Memory. CSCI 315 Operating Systems Design Department of Computer Science
Virtual Memory CSCI 315 Operating Systems Design Department of Computer Science Notice: The slides for this lecture have been largely based on those from an earlier edition of the course text Operating
More informationChapter 6: Demand Paging
ADRIAN PERRIG & TORSTEN HOEFLER ( 5-006-00 ) Networks and Operating Systems Chapter 6: Demand Paging Source: http://redmine.replicant.us/projects/replicant/wiki/samsunggalaxybackdoor If you miss a key
More informationOperating System - Virtual Memory
Operating System - Virtual Memory Virtual memory is a technique that allows the execution of processes which are not completely available in memory. The main visible advantage of this scheme is that programs
More informationChapter 9: Virtual Memory. Operating System Concepts 9th Edition
Chapter 9: Virtual Memory Chapter 9: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped Files Allocating Kernel Memory Other Considerations
More informationBasic Memory Management
Basic Memory Management CS 256/456 Dept. of Computer Science, University of Rochester 10/15/14 CSC 2/456 1 Basic Memory Management Program must be brought into memory and placed within a process for it
More informationChapter 9: Virtual Memory
Chapter 9: Virtual Memory Multiprogramming Memory Management so far 1. Dynamic Loading The main Program gets loaded into memory Routines are stored in Relocatable Load format on disk As main program (or
More informationVirtual Memory COMPSCI 386
Virtual Memory COMPSCI 386 Motivation An instruction to be executed must be in physical memory, but there may not be enough space for all ready processes. Typically the entire program is not needed. Exception
More informationADRIAN PERRIG & TORSTEN HOEFLER Networks and Operating Systems ( ) Chapter 6: Demand Paging
ADRIAN PERRIG & TORSTEN HOEFLER Networks and Operating Systems (5-006-00) Chapter 6: Demand Paging http://redmine.replicant.us/projects/replicant/wiki/samsunggalaxybackdoor (0) # Inverted page table One
More informationModule 9: Virtual Memory
Module 9: Virtual Memory Background Demand Paging Performance of Demand Paging Page Replacement Page-Replacement Algorithms Allocation of Frames Thrashing Other Considerations Demand Segmenation 9.1 Background
More informationChapter 10: Virtual Memory. Background
Chapter 10: Virtual Memory Background Demand Paging Process Creation Page Replacement Allocation of Frames Thrashing Operating System Examples 10.1 Background Virtual memory separation of user logical
More informationChapter 10: Virtual Memory. Background. Demand Paging. Valid-Invalid Bit. Virtual Memory That is Larger Than Physical Memory
Chapter 0: Virtual Memory Background Background Demand Paging Process Creation Page Replacement Allocation of Frames Thrashing Operating System Examples Virtual memory separation of user logical memory
More informationBasic Memory Management. Basic Memory Management. Address Binding. Running a user program. Operating Systems 10/14/2018 CSC 256/456 1
Basic Memory Management Program must be brought into memory and placed within a process for it to be run Basic Memory Management CS 256/456 Dept. of Computer Science, University of Rochester Mono-programming
More informationOperating System Concepts
Chapter 9: Virtual-Memory Management 9.1 Silberschatz, Galvin and Gagne 2005 Chapter 9: Virtual Memory Background Demand Paging Copy-on-Write Page Replacement Allocation of Frames Thrashing Memory-Mapped
More informationOperating Systems. Designed and Presented by Dr. Ayman Elshenawy Elsefy
Operating Systems Designed and Presented by Dr. Ayman Elshenawy Elsefy Dept. of Systems & Computer Eng.. AL-AZHAR University Website : eaymanelshenawy.wordpress.com Email : eaymanelshenawy@yahoo.com Reference
More informationAddresses in the source program are generally symbolic. A compiler will typically bind these symbolic addresses to re-locatable addresses.
1 Memory Management Address Binding The normal procedures is to select one of the processes in the input queue and to load that process into memory. As the process executed, it accesses instructions and
More informationMemory Management and Protection
Part IV Memory Management and Protection Sadeghi, Cubaleska RUB 2008-09 Course Operating System Security Memory Management and Protection Main Memory Virtual Memory Roadmap of Chapter 4 Main Memory Background
More informationChapter 8 & Chapter 9 Main Memory & Virtual Memory
Chapter 8 & Chapter 9 Main Memory & Virtual Memory 1. Various ways of organizing memory hardware. 2. Memory-management techniques: 1. Paging 2. Segmentation. Introduction Memory consists of a large array
More informationWhere are we in the course?
Previous Lectures Memory Management Approaches Allocate contiguous memory for the whole process Use paging (map fixed size logical pages to physical frames) Use segmentation (user s view of address space
More informationMemory Management. CSCI 315 Operating Systems Design Department of Computer Science
Memory Management CSCI 315 Operating Systems Design Department of Computer Science Notice: The slides for this lecture are based on those from Operating Systems Concepts, 9th ed., by Silberschatz, Galvin,
More informationModule 8: Memory Management
Module 8: Memory Management Background Logical versus Physical Address Space Swapping Contiguous Allocation Paging Segmentation Segmentation with Paging Operating System Concepts 8.1 Silberschatz and Galvin
More informationChapter 9: Virtual Memory
Chapter 9: Virtual Memory Chapter 9: Virtual Memory Background Demand Paging Process Creation Page Replacement Allocation of Frames Thrashing Demand Segmentation Operating System Examples 9.2 Background
More informationCourse: Operating Systems Instructor: M Umair. M Umair
Course: Operating Systems Instructor: M Umair Memory Management Introduction { Ref: Operating System Concepts 8th Edition Abraham Silberschatz, Greg Gagne, Peter B. Galvin } Address Binding Addresses in
More informationPart-A QUESTION BANK UNIT-III 1. Define Dynamic Loading. To obtain better memory-space utilization dynamic loading is used. With dynamic loading, a routine is not loaded until it is called. All routines
More informationMemory Management. Disclaimer: some slides are adopted from book authors slides with permission 1
Memory Management Disclaimer: some slides are adopted from book authors slides with permission 1 Demand paging Concepts to Learn 2 Abstraction Virtual Memory (VM) 4GB linear address space for each process
More informationEven in those cases where the entire program is needed, it may not all be needed at the same time (such is the case with overlays, for example).
Chapter 10 VIRTUAL MEMORY In Chapter 9, we discussed various memory-management strategies used in computer systems. All these strategies have the same goal: to keep many processes in memory simultaneously
More informationLast class: Today: Paging. Virtual Memory
Last class: Paging Today: Virtual Memory Virtual Memory What if programs require more memory than available physical memory? Use overlays ifficult to program though! Virtual Memory. Supports programs that
More informationMemory Management. Disclaimer: some slides are adopted from book authors slides with permission 1
Memory Management Disclaimer: some slides are adopted from book authors slides with permission 1 Recap Paged MMU: Two main Issues Translation speed can be slow TLB Table size is big Multi-level page table
More informationLogical versus Physical Address Space
CHAPTER 8: MEMORY MANAGEMENT Background Logical versus Physical Address Space Swapping Contiguous Allocation Paging Segmentation Segmentation with Paging Operating System Concepts, Addison-Wesley 1994
More informationFrequently asked questions from the previous class survey
CS : OPERATING SYSTEMS [VIRTUAL MEMORY] Shrideep Pallickara Computer Science Colorado State University L. Frequently asked questions from the previous class survey Contents of page table entries in multilevel
More informationVIRTUAL MEMORY READING: CHAPTER 9
VIRTUAL MEMORY READING: CHAPTER 9 9 MEMORY HIERARCHY Core! Processor! Core! Caching! Main! Memory! (DRAM)!! Caching!! Secondary Storage (SSD)!!!! Secondary Storage (Disk)! L cache exclusive to a single
More informationVirtual Memory CHAPTER CHAPTER OBJECTIVES. 8.1 Background
Virtual Memory 8 CHAPTER In Chapter 7, we discussed various memory-management strategies used in computer systems. All these strategies have the same goal: to keep many processes in memory simultaneously
More informationPrinciples of Operating Systems
Principles of Operating Systems Lecture 21-23 - Virtual Memory Ardalan Amiri Sani (ardalan@uci.edu) [lecture slides contains some content adapted from previous slides by Prof. Nalini Venkatasubramanian,
More informationProcesses and More. CSCI 315 Operating Systems Design Department of Computer Science
Processes and More CSCI 315 Operating Systems Design Department of Computer Science Notice: The slides for this lecture have been largely based on those accompanying the textbook Operating Systems Concepts,
More informationVII. Memory Management
VII. Memory Management 1 Intended Schedule Date Lecture Hand out Submission 0 20.04. Introduction to Operating Systems Course registration 1 27.04. Systems Programming using C (File Subsystem) 1. Assignment
More informationChapter 8: Memory- Management Strategies. Operating System Concepts 9 th Edition
Chapter 8: Memory- Management Strategies Operating System Concepts 9 th Edition Silberschatz, Galvin and Gagne 2013 Chapter 8: Memory Management Strategies Background Swapping Contiguous Memory Allocation
More informationChapter 8: Memory- Management Strategies
Chapter 8: Memory Management Strategies Chapter 8: Memory- Management Strategies Background Swapping Contiguous Memory Allocation Segmentation Paging Structure of the Page Table Example: The Intel 32 and
More informationChapter 8: Memory- Management Strategies. Operating System Concepts 9 th Edition
Chapter 8: Memory- Management Strategies Operating System Concepts 9 th Edition Silberschatz, Galvin and Gagne 2013 Chapter 8: Memory Management Strategies Background Swapping Contiguous Memory Allocation
More informationChapter 7: Main Memory. Operating System Concepts Essentials 8 th Edition
Chapter 7: Main Memory Operating System Concepts Essentials 8 th Edition Silberschatz, Galvin and Gagne 2011 Chapter 7: Memory Management Background Swapping Contiguous Memory Allocation Paging Structure
More informationVirtual Memory. ICS332 Operating Systems
Virtual Memory ICS332 Operating Systems Virtual Memory Allow a process to execute while not completely in memory Part of the address space is kept on disk So far, we have assumed that the full address
More informationChapter 8: Main Memory
Chapter 8: Main Memory Operating System Concepts 8 th Edition,! Silberschatz, Galvin and Gagne 2009! Chapter 8: Memory Management Background" Swapping " Contiguous Memory Allocation" Paging" Structure
More informationIntroduction to Virtual Memory Management
Introduction to Virtual Memory Management Minsoo Ryu Department of Computer Science and Engineering Virtual Memory Management Page X Demand Paging Page X Q & A Page X Memory Allocation Three ways of memory
More informationOperating Systems. No. 9 ศร ณย อ นทโกส ม Sarun Intakosum
Operating Systems No. 9 ศร ณย อ นทโกส ม Sarun Intakosum 1 Virtual-Memory Management 2 Background Virtual memory separation of user logical memory from physical memory. Only part of the program needs to
More informationChapter 8 Memory Management
Chapter 8 Memory Management Da-Wei Chang CSIE.NCKU Source: Abraham Silberschatz, Peter B. Galvin, and Greg Gagne, "Operating System Concepts", 9th Edition, Wiley. 1 Outline Background Swapping Contiguous
More informationChapter 9 Memory Management Main Memory Operating system concepts. Sixth Edition. Silberschatz, Galvin, and Gagne 8.1
Chapter 9 Memory Management Main Memory Operating system concepts. Sixth Edition. Silberschatz, Galvin, and Gagne 8.1 Chapter 9: Memory Management Background Swapping Contiguous Memory Allocation Segmentation
More informationChapter 8: Main Memory
Chapter 8: Main Memory Chapter 8: Memory Management Background Swapping Contiguous Memory Allocation Paging Structure of the Page Table Segmentation Example: The Intel Pentium 8.2 Silberschatz, Galvin
More informationChapter 8: Memory Management. Operating System Concepts with Java 8 th Edition
Chapter 8: Memory Management 8.1 Silberschatz, Galvin and Gagne 2009 Background Program must be brought (from disk) into memory and placed within a process for it to be run Main memory and registers are
More informationMemory Management. Disclaimer: some slides are adopted from book authors slides with permission 1
Memory Management Disclaimer: some slides are adopted from book authors slides with permission 1 CPU management Roadmap Process, thread, synchronization, scheduling Memory management Virtual memory Disk
More informationChapter 8: Main Memory Chapter 9: Virtual Memory. Operating System Concepts 9th Edition
Chapter 8: Main Memory Chapter 9: Virtual Memory Dr Prabhaker Mateti, CEG 4350 edition This collection is the combined edition of slides for Chapters 8 and 9 of SG, with several slides deleted or modified.
More informationChapter 3: Processes
Chapter 3: Processes Silberschatz, Galvin and Gagne 2013 Chapter 3: Processes Process Concept Process Scheduling Operations on Processes Interprocess Communication 3.2 Silberschatz, Galvin and Gagne 2013
More informationCS 134: Operating Systems
CS 134: Operating Systems More Memory Management CS 134: Operating Systems More Memory Management 1 / 27 2 / 27 Overview Overview Overview Segmentation Recap Segmentation Recap Segmentation Recap Segmentation
More informationMemory Management. To improve CPU utilization in a multiprogramming environment we need multiple programs in main memory at the same time.
Memory Management To improve CPU utilization in a multiprogramming environment we need multiple programs in main memory at the same time. Basic CPUs and Physical Memory CPU cache Physical memory
More informationChapter 3: Processes. Operating System Concepts 8 th Edition,
Chapter 3: Processes, Silberschatz, Galvin and Gagne 2009 Chapter 3: Processes Process Concept Process Scheduling Operations on Processes Interprocess Communication 3.2 Silberschatz, Galvin and Gagne 2009
More informationPage Replacement Algorithms
Page Replacement Algorithms MIN, OPT (optimal) RANDOM evict random page FIFO (first-in, first-out) give every page equal residency LRU (least-recently used) MRU (most-recently used) 1 9.1 Silberschatz,
More informationChapter 3: Processes. Operating System Concepts 9 th Edit9on
Chapter 3: Processes Operating System Concepts 9 th Edit9on Silberschatz, Galvin and Gagne 2013 Chapter 3: Processes 1. Process Concept 2. Process Scheduling 3. Operations on Processes 4. Interprocess
More informationChapter 8: Memory Management Strategies
Chapter 8: Memory- Management Strategies, Silberschatz, Galvin and Gagne 2009 Chapter 8: Memory Management Strategies Background Swapping Contiguous Memory Allocation Paging Structure of the Page Table
More informationChapter 8: Main Memory. Operating System Concepts 9 th Edition
Chapter 8: Main Memory Silberschatz, Galvin and Gagne 2013 Chapter 8: Memory Management Background Swapping Contiguous Memory Allocation Segmentation Paging Structure of the Page Table Example: The Intel
More informationChapter 3: Process-Concept. Operating System Concepts 8 th Edition,
Chapter 3: Process-Concept, Silberschatz, Galvin and Gagne 2009 Chapter 3: Process-Concept Process Concept Process Scheduling Operations on Processes Interprocess Communication 3.2 Silberschatz, Galvin
More informationPage Replacement Chap 21, 22. Dongkun Shin, SKKU
Page Replacement Chap 21, 22 1 Virtual Memory Concept Virtual memory Concept A technique that allows the execution of processes that are not completely in memory Partition each user s program into multiple
More informationCS370: Operating Systems [Spring 2017] Dept. Of Computer Science, Colorado State University
Frequently asked questions from the previous class survey CS : OPERATNG SYSTEMS [VRTUAL MEMORY] Shrideep Pallickara Computer Science Colorado State University Multi-level paging: How many levels deep?
More informationUNIT - IV. What is virtual memory?
UNIT - IV Virtual Memory Demand Paging Process creation Page Replacement Allocation of frames Thrashing- File Concept - Access Methods Directory Structure File System Mounting File Sharing Protection.
More informationChapter 8: Main Memory
Chapter 8: Main Memory Silberschatz, Galvin and Gagne 2013 Chapter 8: Memory Management Background Swapping Contiguous Memory Allocation Segmentation Paging Structure of the Page Table Example: The Intel
More information