An Overview Of Windows NT System Student: Yifan Yang Student ID:

#1. Windows NT Models a>. Client / server model b>. Object model c>. Symmetric multiprocessing #2. Windows NT Structure a>. Protected subsystems b>. Executive

#4. Additional Windows NT Architectures a>. Internationalization b>. Structured exception handling #3. A Brief Tour a>. Logon session b>. Environment subsystems c>. Native services d>. Objects e>. Virtual memory f>. I/O and file systems

#1. Windows NT Models What is an OS Model? It is a broad framework that unifies the many features and services the system provides and the tasks it performs. a >. Client / Server model Windows NT system: Combination of Layered model and client / server model. Layered model is one which divides the O/S into modules and layers them one on top of the other. Each module provides a set of functions that other modules can call. Benefits for using client / server model Simplifies the base OS, the executive. Improves reliability. Lends itself well to a distributed computing model.

Application Program System Services Application Program File System Processor Scheduling Hardware Memory and I/O Device Management User Mode Kernel Mode... Layered Operating System

a >. Client /Server model Is one which devices OS into several processes, each of which implements a single set of services. Client Application Memory Server Network Server Process Server File Server Display Server Microkernel Hardware Client /Server Operating System Reply Send

b >. Object model Object model Is one that any system resources such as files, shared memory and physical devices is implemented as an object and manipulated by using object services so that resources can be shared by more than one process. Benefits for using object model OS can access and manipulate its resources uniformly. Security is simplified because all objects are protected in the same way. Objects provide a convenient and uniform paradigm for sharing resources between two or more processes.

Operating System Operating System User Threa d User Thread User Thread User Threa d Processor AProcessor B Memory MonitorMouseKeyboard I/O Devices Symmetric Multiprocessing c >. Symmetric multiprocessing Symmetric multiprocessing is to allow OS running on any free processor or on all processors simultaneously, sharing memory among them.

Benefits for being multiprocessing system Ability to run OS code on any available processor and on multiple processors at one time. Multiple threads of execution within a single process. Server processes that use multiple threads to process requests from more than one client simultaneously. Convenient mechanisms for sharing objects between processes and flexible interposes communication capabilities, including shared memory and an optimized message-passing facility.

#2. Windows NT Structure The Windows NT’s structure can roughly be divided into two parts: the user-mode portion (protected subsystems) and kernel-mode portion (NT executive).

Object Security ManagerReference Monitor Process Manager Local Procedure Call Facility Virtual Memory Manager I/O Manager File Systems Cache Manager Device Drivers Network Drivers Kernel Hardware Abstraction Layer (HAL) System Trap User Mode Kernel Mode OS/2 Subsystem Win32 Subsystem POSIX Subsystem System Services NT Executive Security subsystem Logon Process OS/2 Clien t Win32 Client POSIX Client Hardware Applications Protected Subsystems (Servers) Message Passing Hardware Manipulation a >. Protected subsystems (environment and integral)

b >. Executive Executive components and their responsibilities: Object Security ManagerReference Monitor Process Manager Local Procedure Call Facility Virtual Memory Manager I/O Manager File Systems Cache Manager Device Drivers Network Drivers Kernel Hardware Abstraction Layer System Services Internal Interfaces System Interfaces

#3. A Brief Tour a >. Logon session Logon Process Security Subsystem Win32 Subsystem User Mode Local Procedure Call (LPC) Logging On

b >. Environment subsystems Each of the environment subsystems supplies an API that its client applications use. Win32 Client Win3 2 Client POSI X Client OS/2 Client 16-Bit Windows Environment MS- DOS Client Win32 Subsyste m POSIX Subsyste m OS/2 Subsyste m Graphical I/O Character I/O ………………………………….. ……………... …………………. Virtual DOS Machines (VDMs) User Mode Kernel Mode Character I/O Local Procedure Call (LPC) Environment Subsystems and Client Applications

c >. Native services They are system services provided by individual components of the NT Object Security ManagerReference Monitor Process Manager Local Procedure Call Facility Virtual Memory Manager I/O Manager File Systems Cache Manager Device Drivers Network Drivers Kernel Hardware Abstraction Layer System Trap Native System Service Call executive. User Mode Kernel Mode OS/2 Subsystem Win32 Subsystem POSIX Subsystem System Services

Many NT native services are object services. Object Security Manager Reference Monitor Process Manager Local Procedure Call Facility Virtual Memory Manager I/O Manager File Systems Cache Manager Device Drivers Network Drivers Kernel Hardware Abstraction Layer User Mode Kernel Mode Win32 Subsystem System Services d >. Objects Create processCreate file Create object Creating NT Objects

e >. Virtual memory addresses in a flat/linear address space. The NT memory architecture is virtual memory based on 32-bit System (2 GB) User Code And Data (2 GB) Resident Operating System Code ………………………. Nonpaged Paged Physical Addressing Range Paged FFFFFFFFh h 7 FFFFFFFh h NT Address Space Layout

Object Security ManagerReference Monitor Process Manager Local Procedure Call Facility Virtual Memory Manager I/O Manager Kernel System Services User Mode Kernel Mode FAT File System Driver NTFS Driver HPFS Driver Floppy Disk Driver Hard Disk Driver Layered Drivers Synchronous as well as asynchronous I/O. Windows NT supports FAT, f >. I/O and file systems... HPFS and NTFS.

#4. Additional / Windows NT Architectures a >. Internationalization A Locale consists of a language, a country, a code set, the binary codes used to represent the characters of a particular language. To facilitate localization, Windows NT’s Win32 subsystem provides a national language support (NLS) API. Unicode, a 16-bit character-coding scheme, can represent 65,536 characters so that it is enough to include all languages in computer commerce today.

FFFFh 0000h ASCII Arabic and Hebrew scripts Dingbats (graphical symbols) Math/technical symbols Punctuation ideographs Chinese/Japanese/Korean Unified Application use Private Compatibility zone Indic scripts Others Latin, Greek, Cyrillic, and Armenian scripts Chinese/Japanese/ Korean symbols (Bopomofo, Hiragana, Katakana, Hangul,…) Future use Provides compatibility with standard, non-Unicode character sets Unicode Layout

b >.Structured exception handling Structured exception handling is the met hod used in windows NT for processing both hardware and software exceptions, using the control structure of a programming language.