The Windows NT 4.0 Environment

1
The Windows NT 4.0 Environment

• Zhudan Zheng
• Southeastern University

2
Introduction

• Microsoft Windows Operating System
• Windows NT Architecture Overview

3
Microsoft Windows Operating Systems

• Windows 95
• Windows NT Workstation
• Comparing Windows 95 to Windows NT Workstation
• Windows NT Server
• Comparing Windows NT Workstation to Windows NT
  Server

4
Windows 95
5
Windows 95 Features

• Feature Benefit
• Desktop performance Supports preemptive
  multitasking for Microsoft Win32 and Microsoft
  MS-DOS-based applications. Windows 95 does not
  support multi microprocessors for true
  multitasking performance.
• Hardware profiles Creates and maintains a list of
  hardware configurations to meet specific computer
  needs.
• Microsoft Internet Provides a browser that is
  fast and simple to use and compatible with
  existing
• Explorer standards.
• Windows Messaging Receives and stores e-mail,
  including files and objects created in other
  applications.
• Compatibility with Runs 32-bit and 16-bit
  Windows- and MS-DOS-based applications. This
  includes
• existing software applications that directly
  access hardware, or those that depend on
  undocumented designs of previous operating
  systems.
• Compatibility with Runs on most computers,
  including hardware that is several years old. The
  minimum
• existing hardware hardware requirements for
  Windows 95 are the following
• Computer with a 386DX/20 or higher
  microprocessor
• 4 MB of RAM (8 MB recommended)
• 40 MB of free disk space (typically)
• Plug and Play support Provides power management
  support for laptop computers, and Plug and Play
  for both portable and desktop systems.

6
Windows NT Workstation
7
Windows NT Workstation Features

• Feature Benefit
• Desktop performance Supports preemptive
  multitasking for all applications. Windows NT
  Workstation supports multiple microprocessors
  for true multitasking performance.
• Hardware profiles Creates and maintains a list of
  hardware configurations to meet specific computer
  needs.
• Microsoft Internet Provides a browser that is
  fast and simple to use and compatible with
  existing
• Explorer standards.
• Windows Messaging Receives and stores e-mail,
  including files and objects created in other
  applications.
• Peer Web services Provides a personal Web server,
  optimized to run on Windows NT Workstation 4.0.
• Security Provides local security for files,
  folders, printers, and other resources. Users
  must be authenticated by either the local
  computer or a domain controller in order to
  access any resources on the computer or
  network.
• Operating system Supports each application in
  its own memory address space. Malfunctioning
• stability applications will not affect other
  applications or the operating system.
• The minimum hardware requirements for Windows NT
  Workstation are
• A computer with a 486DX/33, MIPS R4400-based,
  Digital Alpha AXP-based, or PReP-compliant
  PowerPC-based microprocessor.
• 12 MB of RAM (16 MB recommended on x86 and
  required on RISC).
• 110 MB of free disk space.

8
Comparing Windows 95 to Windows NT
Workstation

• Common Features
• Technical Differences
• Key Decision Criteria
• Mixed Environments

9
Common Features

• Common user interface.
• Common utilities, such as Microsoft Internet
  Explorer
• System policies, user profiles, and hardware
  profiles.

10
Technical Differences

• Windows 95 has less demanding hardware
  requirements.
• Windows 95 has broader application and device
  compatibility.
• Windows 95 offers broad mobile support through
  Advanced Power Management (APM) and Plug and
  Play.
• Windows NT Workstation has higher performance,
  greater reliability, and better security.

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Key Decision Criteria

• Does Windows NT Workstation support all existing
  hardware and applications?
• Is the necessary hardware for Windows NT in
  place?

If the answers to the preceding questions are
yes, Windows NT Workstation may be the best
choice. If the answer to either question is no ,
Windows 95 may be the best choice.
12
Mixed Environments

• For many customers, particularly those who rely
  on mobile computing, a mixed environment of
  Windows 95 and Windows NT Workstation may be the
  most appropriate solution for business needs
• The many common features of the two operating
  systems simplify the tasks of installing,
  managing, and using a mixed operating system
  environment.
• Microsoft provides information to enable
  customers to choose the right mix of systems.
  (Information resources include the Windows 95 and
  Windows NT Workstation Deployment Guides, which
  can be downloaded from www.microsoft.com/)

13
A Comparison of Windows 95 and Windows NT
Workstation

• Technical area Windows 95 Windows NT
  Workstation
• Minimum recommended Lower 486 with 8-16 MB.
  Higher Pentium with 16-32 MB.
• hardware standards
• Software compatibility Very high Supports most
  Windows- High No support for applications that
  breach
• and MS-DOS-based application. Windows NT
  security (any application that directly
  access hardware).
• Hardware and device Very high Supports more
  legacy High Supports most current devices.
• compatibility devices.
• Installation and Comprehensive detection code
  and Less Comprehensive detection code
• deployment dynamic device configuration support
  and static device driver support.
• accurately recognizes, configures,
• and supports hardware.
• APM and Plug and Play Built-in APM support for
  laptops and None Built-in However some APM and
• Plug and Play for both mobile and Plug and
  Play support is available from
• desktop systems. Original Equipment
  Manufacturers (OEMs).
• Performance High Preemptive multitasking for
  Very high Preemptive multitasking for
• 32-bit applications. all applications.
• Reliability/stability High Improved over Windows
  3.11 Very high All applications run in protected
  
• and Windows for Workgroups. memory space.
• Security High Support for server-based Very
  high Complete protection, down to

14
Windows NT Server
15
Windows NT Server Features

• Feature Benefit
• Server performance Tuned for file, print, or
  application server performance. The retail
  version of Windows NT Server supports as many
  as four microprocessors in a symmetric
  multiprocessing environment. (Implementations
  provided by OEMs support up to 32 microprocessors
  in a symmetric multiprocessing environment.)
• 256 Remote Access Provides support for 256
  inbound RAS sessions.
• Service (RAS) sessions
• Fault tolerance Supports Redundant Array of
  Inexpensive Disks (RAID) technology for data
  protection.
• Microsoft Internet Integration of IIS with
  Windows NT Server 4.0 means that Web server
  installation and
• Information Server (IIS) management is simply
  another part of the operating system. With IIS
  2.0 or later, it is possible to remotely
  administer a Web site from any computer with a
  Web browser and to provide a fast and secure
  platform for HTTP, FTP, and Gopher services.
• Administrative wizards Includes wizards that help
  perform common tasks.
• Macintosh client support Provides file and print
  sharing for Macintosh clients.
• Additional network Provides additional network
  services, including multi-protocol routing, DNS
  Server,
• services DHCP, and WINS.
• Windows NT Directory Manages a secure,
  distributed directory database and provides
  services for end users
• Services (NTDS) and network administrators.
• The minimum hardware requirements for Windows NT
  Server on an Intel x86-based computer are
• A personal computer with a 486DX/33 or higher
  microprocessor.
• 16 MB of RAM.
• 125 MB of free disk space.

16
Comparing Windows NT Workstation to Windows NT
Server
Common Features

• Multiple Platforms
• Multitasking and Multithreading Operations
• Security
• etc...

Differences
Windows NT Workstation
Windows NT Server
Multitasking Desktop Operating System
Network Server Operating System
17
Common Features (1)

• The following table shows some of the common
  features and benefits.
• Feature Benefit
• Multiple platform Support for Intel 80486,
  Pentium, and Pentium Pro-based computers, in
  addition to RISC (Reduced instruction set
  computers)-based computers, such as MIPS
  R4x00, DEC Alpha AXP and PReP-compliant
  PowerPC-based systems.
• Additionally, both systems support multiple
  microprocessors and are symmetric
  multiprocessing (SMP) operating systems.
• Multitasking and multi- Different applications
  can run at the same time. Threaded Background
  applications
• threaded operations can continue while a user
  works in the foreground. Multiple threads in an
  application can operate simultaneously.
• Security Security features protect network and
  local resources. Features include mandatory
  logon, discretionary access control, memory
  protection, and auditing.
• Support for MS-DOS-, Most applications run under
  Windows NT. User can work on applications written
• Win16-, Win32-, OS/2-, for other operating
  systems.
• And POSIX-compliant-
• Based applications

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Common Features (2)

• Feature Benefit
• Built-in networking Both operating systems are
  designed for networking. All utilities are
  included with the ability to add networking
  drivers and protocol stacks to meet connectivity
  requirements. Both systems includes a built-in
  Web browser.
• Support for 4 GB of RAM With current hardware,
  there are virtually no capacity limits on
  resources.
• And 16 exabytes (EB) of
• Hard disk space
• File systems Windows NT includes file allocation
  table (FAT), Windows NT File System (NTFS),
  and CD-ROM File System (CDFS).
• Reliability Windows NT supports applications in
  separate memory address space. When
  applications are running in separate memory
  address spaces, malfunctioning applications
  will not affect other applications or the
  operating system. Furthermore, the Windows NT
  architecture protects the operating system from
  applications that attempt to consume too much
  processing time or to use the operating
  systems memory address space.

19
Differences

• The basic difference between Windows NT
  Workstation and Windows NT Server is that Windows
  NT Workstation is designed and tuned as a
  multitasking desktop operating system. Windows NT
  Server contains additional and enhanced features
  that make it a powerful network server operating
  system for server-based applications, such as SQL
  Server, SMS, SNA Server, and Microsoft Exchange
  Server.
• Windows NT Workstation has a limit of 10
  incoming concurrent sessions. For Windows NT
  Server, the number of incoming concurrent
  sessions is limited only by the number of client
  access licenses.

20
Windows NT Architecture

• User Mode vs. Kernel Mode
• The Windows NT Executive

21
User Mode vs. Kernel Mode
22
User Mode

• Applications, and the subsystems that support
  them, run in user mode. User
• mode processes have the following limitations
• No direct access to hardware
• Limited to an assigned address space
• May Need to use hard disk space as virtual RAM
• Process at a lower priority than kernel mode
  components
• User mode processes cannot directly access system
  resources, such as
• hardware. Resource access requests must be
  granted by a kernel mode
• component. This provides protection against
  malfunctioning applications or
• unauthorized user access.User mode processes are
  lower in priority, so they
• have less access to the CPU cycles than processes
  that run in kernel mode.

23
Kernel Mode

• The Windows NT Executive runs in kernel mode to
  protect the Executive services from user mode
  applications and subsystems.
• Kernel mode provides access to all of the memory
  on the computer, and to hardware.
• However, the operating system memory is
  protected applications cannot directly access
  the memory of any kernel mode service.

24
Windows NT Executive
25
Windows NT Executive Components

• There are three types of kernel mode components
  in the Windows NT Executive Executive services,
  the
• microkernel, and the hardware abstraction layer
  (HAL).
• The following table shows the functions of the
  Windows NT Executive components
• Component Function
• Executive services The Executive services consist
  of managers and device drives.
• Managers are the various modules that manage
  I/O, objects, security, processes, interprocess
  communications (IPC), virtual memory, and window
  and graphics management.
• Device drives are modules that control
  hardware access.
• Microkernel A component of the Executive
  services that provides the most basic operating
  system services, such as thread scheduling and
  interrupt handling.
• HAL Code that isolates most hardware interface
  differences from Windows NT, making Windows NT
  more portable.

26
Subsystems Overview
Environment Subsystems
27
Environment Subsystem

• An environment subsystem in Windows NT is an
  intermediary between an application designed for
  a specific operating environment and the
  Executive services.
• The environment subsystem translates
  environment-specific instructions from an
  application into instructions that the Executive
  services can carry out.
• These are two Windows NT environment subsystems
  that support applications designed for other
  operating environments the POSIX subsystem and
  the OS/2 subsystem. These subsystems receive all
  function requests from the applications that they
  support.
• A subsystem either carries out the request itself
  or passes it to the Windows NT Executive.

28
Win32 Subsystem

• The Win32 subsystem is sometimes referred to as
  the client/server subsystem, the CSR subsystem,
  or CSRSS. It supports Win32-, MS-DOS-, and
  Windows 3.x-based applications and the
  environment subsystems.
• TheWin32 subsystem also supports error handling
  functions, application shutdown, and console
  applicationsapplications not written for the
  Windows GUI.

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Executive Services

• The Windows NT Executive performs basic operating
  system functions for all subsystems. The
  Executive services reside in kernel mode. This
  provides stability for the operating system,
  because no application or subsystem can directly
  access the Executive services. In this way, a
  malfunctioning user-mode component (such as an
  application or environment subsystem) cannot
  cause a kernel mode component to stop
  functioning.
• All GUI-related I/O requests are channeled to the
  Win32K Window Manager GDI component of the
  Executive services, which is responsible for
  maintaining the display. This provides a common
  GUI for all applications.
• The subsystems build on the Executive services to
  produce environments that meet the specific needs
  of their client applications. In this way, common
  operating system functions are implemented once
  in the Executive services, rather than duplicated
  in each subsystem. This reduces the effort
  required to develop new subsystems and makes them
  easier to maintain.

30
Review

• Microsoft Windows Operating System
• Windows NT Architecture Overview