OPERATING SYSTEM CONCEPTS 9TH EDITION PPT

ệu tham khu tham khảảoo1. Abraham Silberschatz, Peter Baer Galvin, Greg Gagne,Operating System Concepts, 7th edition, John Wlley & Sons.INC, 2005.2. Partha Dasgupta, Network Operating Systems, Arizona StateUniversity, 1997.3. William Stallings, Operating[r]

thEdition, Feb 14, 2005Safe StateSafe 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 sequence <P1, P2, …, Pn> of ALL the processes is the[r]

 Resource Sharing Economy Utilization of MP Architectures4.5Silberschatz, Galvin and Gagne ©2005Operating System Concepts – 7thedition, Jan 23, 2005User ThreadsUser Threads Thread management done by user-level threads library Three primary thread libraries:z POSIX Pthreadsz[r]

File Manipulation A file is a sequence of bytes; the kernel does not impose a structure on files Files are organized in tree-structured directories Directories are files that contain information on how to find other files Path name: identifies a file by specifying a path through the directory st[r]

Chapter 14: ProtectionChapter 14: Protection14.2Silberschatz, Galvin and Gagne ©2005Operating System Concepts – 7thEdition, Apr 11, 2005Chapter 14: ProtectionChapter 14: Protection Goals of Protection  Principles of Protection Domain of Protection  Access Matrix  Implementa[r]

generating messages from ciphertexts.  Both D and D(k) for any k should be efficiently computable functions. An encryption algorithm must provide this essential property: Given a ciphertext c ∈C, a computer can compute m such that E(k)(m) = c only if it possesses D(k). z Thus, a computer holding D[r]

Operating System Definition (Cont.)Operating System Definition (Cont.) No universally accepted definition “Everything a vendor ships when you order an operating system”is good approximationz But varies wildly “The one program running at all times on the c[r]

 Standard, precompiled sets of packages, or distributions, include the basic Linux system, system installation and management utilities, and ready-to-install packages of common UNIX tools The first distributions managed these packages by simply providing a means of unpacking all the[r]

Chapter 19: RealChapter 19: Real--Time SystemsTime Systems19.2Silberschatz, Galvin and Gagne ©2005Operating System Concepts – 7thEdition, Jan 1, 2005Chapter 19: RealChapter 19: Real--Time SystemsTime Systems System Characteristics Features of Real-Time Systems Implemen[r]

Schedulers Long-term scheduler (or job scheduler) – selects which processes should be brought into the ready queue Short-term scheduler (or CPU scheduler) – selects which process should be executed next and allocates CPU3.14Silberschatz, Galvin and Gagne ©2005Operating System Conc[r]

Operating System Concepts – 7thEdition, Jan 2, 2005What is Multimedia?What is Multimedia? Multimedia data includes- audio and video clips (i.e. MP3 and MPEG files)- live webcasts Multimedia data may be delivered to- desktop PC’s- handheld devices (PDAs, smart phones20.5Silbers[r]

Chapter 8: Main MemoryChapter 8: Main Memory8.2Silberschatz, Galvin and Gagne ©2005Operating System Concepts – 7thEdition, Feb 22, 2005Chapter 8: Memory ManagementChapter 8: Memory Management Background Swapping  Contiguous Memory Allocation Paging Structure of the Page Tab[r]

Silberschatz, Galvin and Gagne ©2005Operating System Concepts – 7thEdition, Feb 8, 2005SemaphoreSemaphore Synchronization tool that does not require busy waiting  Semaphore S – integer variable Two standard operations modify S: wait() and signal()z Originally called P() and V[r]

to clients and across server farms.The Windows Server 2003 family and applications built with the .NET Framework are scalable by design. Not only does the Windows Server 2003 family offer rich servers, from a basic Web Edition through an advanced Datacenter Edition, the same industry-s[r]

directory tree obeying UNIX semantics. Internally, the kernel hides implementation details and manages the multiple different file systems via an abstraction layer, that is, the virtual file system (VFS). The Linux VFS is designed around object-oriented principles and is composed of two com[r]

 The kernel provides trap handling when exceptions and interruptsare generated by hardware of software Exceptions that cannot be handled by the trap handler are handled by the kernel's exception dispatcher The interrupt dispatcher in the kernel handles interrupts by calling either an interrupt se[r]

ConceptsKernel Synchronization (Cont.)Linux uses two techniques to protect critical sections:1. Normal kernel code is nonpreemptible– when a time interrupt is received while a process is executing a kernel system service routine, the kernel’s need_resched flag is set so that the scheduler w[r]

 Scheduling under 1 and 4 is nonpreemptive All other scheduling is preemptive5.7Silberschatz, Galvin and Gagne ©2005Operating System Concepts – 7thEdition, Feb 2, 2005DispatcherDispatcher Dispatcher module gives control of the CPU to the process selected by the short-term sch[r]

Transfer rate is rate at which data flow between drive and computer●Positioning time (random-access time) is time to move disk arm to desired cylinder (seek time) and time for desired sector to rotate under the disk head (rotational latency)●Head crash results from disk head making contact with the[r]

Storage Area Network■Common in large storage environments (and becoming more common)■Multiple hosts attached to multiple storage arrays - flexible12.11Silberschatz, Galvin and Gagne ©2005Operating System Concepts – 7th Edition, Jan 1, 2005Disk SchedulingDisk Scheduling■Th[r]