Chapter 21: Windows 10 Operating System Concepts – 10th dition Silberschatz, Galvin and Gagne ©2018 Chapter 21: Windows History Design Principles System Components Terminal Services and Fast User Switching File System Networking Programmer Interface Operating System Concepts – 10th dition 21!2 Silberschatz, Galvin and Gagne ©2018 Objectives Explore the principles upon which Windows 10 is designed and the specific components involved in the system Provide a detailed e!planation of the Windows 10 file system Illustrate the networking protocols supported in Windows $% Describe the interface available in Windows 10 to system and application programmers Describe the important algorithms implemented in #indows 10 Operating System Concepts – 10th dition 21!" Silberschatz, Galvin and Gagne ©2018 History In 198)* Microsoft decided to develop a “new technology” (NT) portable operating system that supported 'oth the OS/2 and POSIX APIs Originally, NT was supposed to "se the OS/2 API as its native environment 'ut during development NT was changed to use the Win32 API, reflecting the popularity of Windows 3.0. Many versions of Windows along the way, XP, Vista* 7, 8, and now 10 Many older versions still in use, less secure, some unpatched Operating System Concepts – 10th dition 21!# Silberschatz, Galvin and Gagne ©2018 Windows 10 52: and ;<:bit preemptive multitasking operating system for Intel microprocessors =ey goals for the system> portability security P0SI3 compliance multiprocessor support extensi'ility international support compatibility with +S:D0S and +S:Windows applications Uses a micro-kernel architecture Several versions with di?erent prices* for devices1laptops/desktops and servers Win 10 has an app store, Windows Desktop @ridge to run older binaries, Pico Providers replacing the old multiple subsystem concept* Hyper-V virtualiAation, multi"ser* distri'"ted services* remote BUI* and other advanced feat"res Operating System Concepts – 10th dition 21!$ Silberschatz, Galvin and Gagne ©2018 Design Principles Security : *ccess control lists .*CLs/ C 'oth attri'"te:'ased and claim: 'ased D"dimentary capa'ilities f"nctionally called integrity levels File system and comm"nication encryption xploit mitigations C address-space layout randomization .ASLR/* .ata Execution Prevention .. %/* Control-Flow Guard .CFG/* and Arbitrary Code Guard .*CG/ Several digital signat"re facilities .evice Guard option for &ne grain control over what signers code is allowed on the system Operating System Concepts – 10th dition 21!) Silberschatz, Galvin and Gagne ©2018 Design Principles (Cont.) xtensi'ility — layered architect"re -emote procedure calls .RPCs/ *dvanced local procedure calls .*+PCs/ Porta'ility E #indows $% can 'e moved from one hardware architect"re to another with relatively few changes #ritten in C and CFF Processor:speci&c portions are written in assem'ly lang"age for a given processor architect"re .small amo"nt of s"ch code/7 Platform:dependent code is isolated in a dynamic link li'rary .DGG/ called the ,hardware a'straction layer- .H4G/ Operating System Concepts – 10th dition 21!2 Silberschatz, Galvin and Gagne ©2018 Design Principles (Cont.) Delia'ility — Windows $% uses hardware protection for virt"al memory, and software protection mechanisms for operating system resources Compatibility — applications that follow the I $%%57$ .P0SI3/ standard can be complied to run on $% without changing the source code Performance E #indows $0 su'systems can comm"nicate with one another via high-performance message passing Preemption of low priority threads enables the system to respond Huickly to external events Designed for symmetrical multiprocessing International support — supports different locales via the national language support .NGS/ 4PI nergy efficiency – for portable devices, etc, incl"des dynamic tick feat"re* process lifetime management* desktop activity monitor* connected stand'y Operating System Concepts – 10th dition 21!8 Silberschatz, Galvin and Gagne ©2018 Windows 10 Architecture Layered system of module Protected mode — hardware abstraction layer .&*+/, kernel, executive User mode — collection of subsystems Environmental subsystems emulate di?erent operating systems Protection s"bsystems provide security f"nctions Operating System Concepts – 10th dition 21!3 Silberschatz, Galvin and Gagne ©2018 Depiction of 10 Architecture Operating System Concepts – 10th dition 21!10 Silberschatz, Galvin and Gagne ©2018 System Components Layered system of modules operating at specific privilege layers Kernel and "ser mode of course Virtual Tr,st Levels .(4Ls) option implemented 'y Hyper-8 virtualization Enables virt"al secure mode Normal World .8TG %/ and Sec,re World (VTL 1) #ithin each world are "ser and kernel modes Secure world has a secure kernel and executive and a collection of tr,stlets Bottommost layer runs in special processor mode .8+3 Root Mode on Intel) including Hyper-V hypervisor, creating hardware-based normal-to-secure-world 'oundary Operating System Concepts – 10th dition 21!11 Silberschatz, Galvin and Gagne ©2018 System Components — Kernel Fo"ndation for the executive and the su'systems Never paged out of memoryJ execution is never preempted Fo"r main responsibilities: thread sched"ling interrupt and exception handling low:level processor synchronization recovery after a power fail"re =ernel is o'Kect:oriented, uses two sets of obKects dispatcher objects control dispatching and synchronization .events, mutants, mutexes, semaphores, threads and timers/ control objects .asynchronous proced"re calls, interr"pts* power notify, power status* process and profile obKects) 8S+ nclaves allow valid signed third:party code to perform crypto calculations Operating System Concepts – 10th dition 21!12 Silberschatz, Galvin and Gagne ©2018 Kernel — Process and Threads The process has a virtual memory address space* information (such as a base priority/* and an affinity for one or more processors Threads are the unit of execution scheduled by the kernelLs dispatcher ach thread has its own state* including a priority* processor affinity* and accounting information 4 thread can 'e one of eight states: initializing* ready, deferred- ready, standby, running, waiting, transition* and terminated ach thread has two modes of execution> ,ser-mode thread .74/ and kernel'mode thread .94/ ach has two stacks, one for each mode =ernel layer runs trap handler to switch stacks and change CPU mode Operating System Concepts – 10th dition 21!1" Silberschatz, Galvin and Gagne ©2018 Kernel — Scheduling The dispatcher "ses a 52-level priority scheme to determine the order of thread execution7 Priorities are divided into two classes The real-time class contains threads with priorities ranging from 16 to 31 The variable class contains threads having priorities from 0 to 15 Characteristics of Windows 10’s priority strategy Trends to give very good response times to interactive threads that are "sing the mouse and windows Enables I/O-bound threads to keep the I/O devices 'usy Complete-bound threads soak up the spare CPU cycles in the background Operating System Concepts – 10th dition 21!1# Silberschatz, Galvin and Gagne ©2018 Kernel — Scheduling (Cont.) 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 aInity Real-time threads are given preferential access to the CPU; but 10 does not guarantee that a real-time thread will start to execute within any particular time limit This is known as soft realtime Operating System Concepts – 10th dition 21!1$ Silberschatz, Galvin and Gagne ©2018 Windows x86 Interrupt Request Levels Operating System Concepts – 10th dition 21!1) Silberschatz, Galvin and Gagne ©2018 Kernel — Trap Handling The kernel provides trap handling when exceptions and interrupts are generated 'y hardware of software Exceptions that cannot be handled 'y the trap handler are handled 'y the kernel's exception dispatcher 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 The kernel "ses spin locks that reside in global memory to achieve multiprocessor mutual exclusion Operating System Concepts – 10th dition 21!12 Silberschatz, Galvin and Gagne ©2018 Executive — Object Manager Windows 7 uses objects for all its services and entities; the object manger supervises the use of all the o'Kects Generates an object handle Checks security Keeps track of which processes are using each object Objects are manipulated by a standard set of methods, namely create, open, close, delete, query name, parse and security7 Operating System Concepts – 10th dition 21!18 Silberschatz, Galvin and Gagne ©2018 Executive — Naming Objects The Windows 7 executive allows almost any object to be given a name* which may 'e either permanent or temporary Exceptions are process, thread and some others object types 0'Kect names are struct"red like file path names in MS-DOS and UNIX #indows 7 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 A process gets an o'Kect handle 'y creating an object 'y opening an existing one* by receiving a duplicated handle from another process, or 'y inheriting a handle from a parent process Each object is protected 'y an access control list Operating