Bài giảng Hệ điều hành nâng cao - Chapter 22: Windows XP

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Bài giảng Hệ điều hành nâng cao - Chapter 22: Windows XP

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Bài giảng Hệ điều hành nâng cao - Chapter 22: Windows XP trình bày về lịch sử Windows XP, nguyên tắc thiết kế, hệ thống thành phần, mạng, hệ thống tập tin, giao diện lập trình, hệ thống con,...Mời bạn đọc cùng tham khảo.

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  1. Chapter 22: Windows XP Operating System Concepts – 8th Edition Operating System Concepts – 8th Edition 22.1 Silberschatz, Galvin and Gagne ©2009
  2. Chapter 22: Windows XP s History s Design Principles s System Components s Environmental Subsystems s File system s Networking s Programmer Interface Operating System Concepts – 8th Edition 22.2 Silberschatz, Galvin and Gagne ©2009
  3. Objectives s To explore the principles upon which Windows XP is designed and the specific components involved in the system s To understand how Windows XP can run programs designed for other operating systems s To provide a detailed explanation of the Windows XP file system s To illustrate the networking protocols supported in Windows XP s To cover the interface available to system and application programmers Operating System Concepts – 8th Edition 22.3 Silberschatz, Galvin and Gagne ©2009
  4. Windows XP s 32-bit preemptive multitasking operating system for Intel microprocessors s Key goals for the system: q portability q security q POSIX compliance q multiprocessor support q extensibility q international support q compatibility with MS-DOS and MS-Windows applications. s Uses a micro-kernel architecture s Available in four versions, Professional, Server, Advanced Server, National Server Operating System Concepts – 8th Edition 22.4 Silberschatz, Galvin and Gagne ©2009
  5. History s In 1988, Microsoft decided to develop a “new technology” (NT) portable operating system that supported both the OS/2 and POSIX APIs. s Originally, NT was supposed to use the OS/2 API as its native environment but during development NT was changed to use the Win32 API, reflecting the popularity of Windows 3.0. Operating System Concepts – 8th Edition 22.5 Silberschatz, Galvin and Gagne ©2009
  6. Design Principles s Extensibility — layered architecture q Executive, which runs in protected mode, provides the basic system services q On top of the executive, several server subsystems operate in user mode q Modular structure allows additional environmental subsystems to be added without affecting the executive s Portability —XP can be moved from on hardware architecture to another with relatively few changes q Written in C and C++ q Processor-dependent code is isolated in a dynamic link library (DLL) called the “hardware abstraction layer” (HAL) Operating System Concepts – 8th Edition 22.6 Silberschatz, Galvin and Gagne ©2009
  7. Design Principles (Cont.) s Reliability —XP uses hardware protection for virtual memory, and software protection mechanisms for operating system resources s Compatibility — applications that follow the IEEE 1003.1 (POSIX) standard can be complied to run on XP without changing the source code s Performance —XP subsystems can communicate with one another via high-performance message passing q Preemption of low priority threads enables the system to respond quickly to external events q Designed for symmetrical multiprocessing s International support — supports different locales via the national language support (NLS) API Operating System Concepts – 8th Edition 22.7 Silberschatz, Galvin and Gagne ©2009
  8. XP Architecture s Layered system of modules s Protected mode — hardware abstraction layer (HAL), kernel, executive s User mode — collection of subsystems q Environmental subsystems emulate different operating systems q Protection subsystems provide security functions Operating System Concepts – 8th Edition 22.8 Silberschatz, Galvin and Gagne ©2009
  9. Depiction of XP Architecture Operating System Concepts – 8th Edition 22.9 Silberschatz, Galvin and Gagne ©2009
  10. System Components — Kernel s Foundation for the executive and the subsystems s Never paged out of memory; execution is never preempted s Four main responsibilities: q thread scheduling q interrupt and exception handling q low-level processor synchronization q recovery after a power failure s Kernel is object-oriented, uses two sets of objects q dispatcher objects control dispatching and synchronization (events, mutants, mutexes, semaphores, threads and timers) q control objects (asynchronous procedure calls, interrupts, power notify, power status, process and profile objects) Operating System Concepts – 8th Edition 22.10 Silberschatz, Galvin and Gagne ©2009
  11. Kernel — Process and Threads s The process has a virtual memory address space, information (such as a base priority), and an affinity for one or more processors. s Threads are the unit of execution scheduled by the kernel’s dispatcher. s Each thread has its own state, including a priority, processor affinity, and accounting information. s A thread can be one of six states: ready, standby, running, waiting, transition, and terminated. Operating System Concepts – 8th Edition 22.11 Silberschatz, Galvin and Gagne ©2009
  12. Kernel — Scheduling s The dispatcher uses a 32-level priority scheme to determine the order of thread execution. q Priorities are divided into two classes 4 The real-time class contains threads with priorities ranging from 16 to 31 4 The variable class contains threads having priorities from 0 to 15 s Characteristics of XP’s priority strategy q Trends to give very good response times to interactive threads that are using the mouse and windows q Enables I/O-bound threads to keep the I/O devices busy q Complete-bound threads soak up the spare CPU cycles in the background Operating System Concepts – 8th Edition 22.12 Silberschatz, Galvin and Gagne ©2009
  13. Kernel — Scheduling (Cont.) s Scheduling can occur when a thread enters the ready or wait state, when a thread terminates, or when an application changes a thread’s priority or processor affinity. s Real-time threads are given preferential access to the CPU; but XP does not guarantee that a real-time thread will start to execute within any particular time limit . q This is known as soft realtime. Operating System Concepts – 8th Edition 22.13 Silberschatz, Galvin and Gagne ©2009
  14. Windows XP Interrupt Request Levels Operating System Concepts – 8th Edition 22.14 Silberschatz, Galvin and Gagne ©2009
  15. Kernel — Trap Handling s The kernel provides trap handling when exceptions and interrupts are generated by hardware of software. s Exceptions that cannot be handled by the trap handler are handled by the kernel's exception dispatcher. s The interrupt dispatcher in the kernel handles interrupts by calling either an interrupt service routine (such as in a device driver) or an internal kernel routine. s The kernel uses spin locks that reside in global memory to achieve multiprocessor mutual exclusion. Operating System Concepts – 8th Edition 22.15 Silberschatz, Galvin and Gagne ©2009
  16. Executive — Object Manager s XP uses objects for all its services and entities; the object manger supervises the use of all the objects q Generates an object handle q Checks security q Keeps track of which processes are using each object s Objects are manipulated by a standard set of methods, namely create, open, close, delete, query name, parse and security. Operating System Concepts – 8th Edition 22.16 Silberschatz, Galvin and Gagne ©2009
  17. Executive — Naming Objects s The XP executive allows any object to be given a name, which may be either permanent or temporary. s Object names are structured like file path names in MS-DOS and UNIX. s XP implements a symbolic link object, which is similar to symbolic links in UNIX that allow multiple nicknames or aliases to refer to the same file. s A process gets an object handle by creating an object by opening an existing one, by receiving a duplicated handle from another process, or by inheriting a handle from a parent process. s Each object is protected by an access control list. Operating System Concepts – 8th Edition 22.17 Silberschatz, Galvin and Gagne ©2009
  18. Executive — Virtual Memory Manager s The design of the VM manager assumes that the underlying hardware supports virtual to physical mapping a paging mechanism, transparent cache coherence on multiprocessor systems, and virtual addressing aliasing. s The VM manager in XP uses a page-based management scheme with a page size of 4 KB. s The XP VM manager uses a two step process to allocate memory q The first step reserves a portion of the process’s address space q The second step commits the allocation by assigning space in the 2000 paging file Operating System Concepts – 8th Edition 22.18 Silberschatz, Galvin and Gagne ©2009
  19. Virtual-Memory Layout Operating System Concepts – 8th Edition 22.19 Silberschatz, Galvin and Gagne ©2009
  20. Virtual Memory Manager (Cont.) s The virtual address translation in XP uses several data structures q Each process has a page directory that contains 1024 page directory entries of size 4 bytes. q Each page directory entry points to a page table which contains 1024 page table entries (PTEs) of size 4 bytes. q Each PTE points to a 4 KB page frame in physical memory. s A 10-bit integer can represent all the values form 0 to 1023, therefore, can select any entry in the page directory, or in a page table. s This property is used when translating a virtual address pointer to a bye address in physical memory. s A page can be in one of six states: valid, zeroed, free standby, modified and bad. Operating System Concepts – 8th Edition 22.20 Silberschatz, Galvin and Gagne ©2009

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