Lecture15nFulll - Click to edit Master subtitle style...

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Unformatted text preview: Click to edit Master subtitle style 8/1/11 Lecture 15 COP 4600 Operating Systems Spring 2011 Dan C. Marinescu Office: HEC 304 Office hours: Tu-Th 5:00-6:00 PM Lecture 15 8/1/11 n Last time: Midterm solutions n Today: n Virtualization for the three abstractions Threads Virtual Memory Bounded buffer n The kernel of an operating system n Threads State Thread manager Thread state Kernel and application threads Next time n Processor switching Lecture 15 Thursday, March 17, 2011 Lecture 15 22 Lecture 15 8/1/11 Virtualization relating physical with virtual objects n Virtualization & simulating the interface to a physical object by: 1. Multiplexing T create multiple physical objects from one instance of a physical object. 2. Aggregation create one virtual object from multiple physical objects 3. Emulation construct a virtual object from a different type of a physical object. Emulation in software is slow. Method Physical Resource Virtual Resource Multiplexing processor thread real memory virtual memory communication channel virtual circuit processor server (e.g., Web server) Aggregation disk RAID core multi-core processor Emulation disk RAM disk system (e.g. Macintosh) virtual machine (e.g., Virtual PC) Multiplexing + Emulation real memory + disk virtual memory with paging communication channel + processor TCP protocol 33 Lecture 15 Lecture 15 8/1/11 Virtualization of the three abstractions n We analyze virtualization for the three abstractions 1. Interpreter ' Threads 2. Communication link/channel & Bounded Buffer 3. Storage ' Virtual Memory Lecture 15 44 Lecture 15 8/1/11 (1) Virtualization of interpreter - Threads n Process/Threads f a virtual processor n Multiplexing or processor sharing is possible because there is a significant discrepancy between processor bandwidth and the bandwidth of memory and of I/O devices threads spend a significant percentage of their lifetime waiting for external events. n Called: Time-sharing Processor multiplexing Multiprogramming Multitasking n Processes versus thread: Both represent a module in execution A process may consist of multiple threads A thread is a light-weight process, less overhead to create it. 55 Lecture 15 Lecture 15 8/1/11 Lecture 15 66 Lecture 15 8/1/11 Tight coupling between interpreter and storage n We need a memory enforcement mechanism; to prevent a thread running the code of one module from overwriting the data of another module. n Address space 9 the range of memory addresses a thread is allowed to access....
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This note was uploaded on 07/30/2011 for the course COP 4600 taught by Professor Montagne during the Spring '08 term at University of Central Florida.

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Lecture15nFulll - Click to edit Master subtitle style...

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