Download An Overview Of Windows Nt System

An Overview Of Windows NT
System
Student: Yifan Yang
Student ID: 102525
#1. Windows NT Models
a>. Client / server model
b>. Object model
c>. Symmetric multiprocessing
#2. Windows NT Structure
a>. Protected subsystems
b>. Executive
#3. A Brief Tour
a>. Logon session
b>. Environment subsystems
c>. Native services
d>. Objects
e>. Virtual memory
f>. I/O and file systems
#4. Additional Windows NT Architectures
a>. Internationalization
b>. Structured exception handling
#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
...
Application
Program
User Mode
System Services
File System
Memory and I/O Device Management
Processor Scheduling
Hardware
Layered Operating System
Kernel Mode
• a>. Client /Server model
• Is one which devices OS into several processes, each of
which implements a single set of services.
Client
Application
Reply
Network
Server
Memory
Server
Process
Server
File
Server
Send
Microkernel
Hardware
Client /Server Operating System
Display
Server
• 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.
• c>. Symmetric multiprocessing
• Symmetric multiprocessing is to allow OS running on any
free processor or on all processors simultaneously, sharing
memory among them.
Memory
Processor A
Processor B
Operating
System
User
Thread
User
Threa
d
User
Threa
d
User
Thread
Operating
System
Monitor
Symmetric Multiprocessing
Mouse
Keyboard
I/O Devices
• 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).
a>. Protected subsystems (environment and integral)
Applications
Protected
Subsystems
(Servers)
Logon
Process
OS/2
Clien
t
POSIX
Client
Win32
Client
OS/2
Subsystem
Security
subsystem
Win32
Subsystem
POSIX
Subsystem
User Mode
Kernel Mode
System Services
Object
Security Process
Local
Manager Reference Manager Procedure
Monitor
NT Executive
Call Facility
Virtual
Memory
Manager
Kernel
System Trap
Message Passing
Hardware Manipulation
Hardware Abstraction Layer (HAL)
Hardware
I/O Manager
File Systems
Cache Manager
Device Drivers
Network Drivers
b>. Executive
Executive components and their responsibilities:
Object
Security Process
Local
Manager Reference Manager Procedure
Monitor
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.
Win3
2
Client
Win32
Client
Virtual DOS
Machines
(VDMs)
…………………………………..
16-Bit
Windows
Environment
……………...
MSGraphical I/O
DOS
Client
………………….
Character I/O
POSI
X
Client
POSIX
Subsyste
m
OS/2
Client
OS/2
Subsyste
m
Character I/O
Win32
Subsyste
m
Character I/O
User Mode
Kernel Mode
Local Procedure Call (LPC)
Environment Subsystems and Client Applications
c>. Native services
They are system services provided by individual components of the NT
executive.
OS/2
Subsystem
Win32
Subsystem
POSIX
Subsystem
User Mode
Kernel Mode
System Services
Object
Security Process
Local
Manager Reference Manager Procedure
Monitor
Call Facility
Virtual
Memory
Manager
I/O Manager
File Systems
Cache Manager
Device Drivers
Kernel
Hardware Abstraction Layer
System Trap
Native System Service Call
Network Drivers
d>. Objects
Many NT native services are object services.
Win32
Subsystem
Create process
Create file
User Mode
Kernel Mode
System Services
Create object
Create object
I/O Manager
File Systems
Security Process
Local
Object
Reference
Procedure
Manager
Manager Monitor
Call Facility
Virtual
Memory
Manager
Cache Manager
Device Drivers
Network Drivers
Kernel
Hardware Abstraction Layer
Creating NT Objects
e>. Virtual memory
The NT memory architecture is virtual memory based on 32-bit
addresses in a flat/linear address space.
FFFFFFFFh
Nonpaged
System
(2 GB)
80000000h
……………………….
Resident Operating
System Code
Paged
Physical Addressing Range
7FFFFFFFh
User Code
And Data
(2 GB)
00000000h
NT Address Space Layout
Paged
f>. I/O and file systems
Synchronous as well as asynchronous I/O. Windows NT supports FAT,
HPFS and NTFS.
User Mode
Kernel Mode
System Services
Object
Security Process
Local
Manager Reference Manager Procedure
Monitor
Call Facility
Virtual
Memory
Manager
I/O Manager
Kernel
FAT File
System Driver
Floppy
Disk Driver
Layered Drivers
NTFS
Driver
HPFS ...
Driver
Hard
Disk Driver
#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.
Punctuation
Math/technical symbols
Dingbats (graphical symbols)
Arabic and
Hebrew scripts
Unified
Chinese/Japanese/Korean
ideographs
ASCII
Private
Application use
0000h
FFFFh
Indic scripts
Others
Latin,
Greek,
Cyrillic, and
Armenian scripts
Compatibility
zone
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.