The Windows NT 4.0 The Windows NT 4.0 EnvironmentEnvironment

Zhudan ZhengZhudan Zheng

Southeastern Southeastern UniversityUniversity

IntroductionIntroduction

Microsoft Windows Operating System

Windows NT Architecture Overview

Microsoft Windows Microsoft Windows Operating Systems 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

Windows 95Windows 95

Windows 95 FeaturesWindows 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 existingExplorer 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 microprocessor4 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.

Windows NT WorkstationWindows NT Workstation

Windows NT Workstation FeaturesWindows 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 existingExplorer 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.

Comparing Windows 95 to Comparing Windows 95 to Windows NT Workstation Windows NT Workstation

Common Features

Technical Differences

Key Decision Criteria

Mixed Environments

Common FeaturesCommon Features

Common user interface. Common utilities, such as Microsoft

Internet Explorer System policies, user profiles, and

hardware profiles.

Technical DifferencesTechnical 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.

KeyKey DecisionDecision CriteriaCriteria

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.

MixedMixed EnvironmentsEnvironments

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/)

A Comparison of Windows 95 and A Comparison of Windows 95 and Windows NT WorkstationWindows NT Workstation

Technical area Windows 95 Windows NT WorkstationMinimum recommended Lower: 486 with 8-16 MB. Higher: Pentium with 16-32 MB.hardware standardsSoftware 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 validation of the logon process. the file level.

Windows NT ServerWindows NT Server

Windows NT Server FeaturesWindows NT Server Features

Feature BenefitServer 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) sessionsFault 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 networkProvides 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 usersServices (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.

Comparing Windows NT Workstation Comparing Windows NT Workstation to Windows NT Serverto Windows NT Server

Multiple Platforms Multitasking and Multithreading Operations Security etc...

Differences

Windows NT Workstation Windows NT Server

Multitasking Desktop

Operating System

Network Server

Operating System

Common Features

Common Features (1)Common Features (1)

The following table shows some of the common features and benefits.

Feature BenefitMultiple 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 applicationsthreaded 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 writtenWin16-, Win32-, OS/2-, for other operating systems.And POSIX-compliant-Based applications

Common Features (2)Common Features (2)

Feature Benefit

Built-in networkingBoth 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) ofHard disk spaceFile 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 system’s memory address space.

DifferencesDifferences

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.

Windows NT ArchitectureWindows NT Architecture

User Mode vs. Kernel Mode

The Windows NT Executive

User Mode vs. Kernel ModeUser Mode vs. Kernel Mode

UserUser ModeMode

Applications, and the subsystems that support them, run in user mode. Usermode 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 componentsUser mode processes cannot directly access system resources, such ashardware. Resource access requests must be granted by a kernel modecomponent. This provides protection against malfunctioning applications orunauthorized user access.User mode processes are lower in priority, so theyhave less access to the CPU cycles than processes that run in kernel mode.

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.

Windows NT ExecutiveWindows NT Executive

Windows NT Executive ComponentsWindows NT Executive Components

There are three types of kernel mode components in the Windows NT Executive: Executive services, themicrokernel, and the hardware abstraction layer (HAL).

The following table shows the functions of the Windows NT Executive components

Component FunctionExecutive 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.

Subsystems OverviewSubsystems Overview

Environment Subsystems

Environment SubsystemEnvironment 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.

Win32 SubsystemWin32 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 applications—applications not written for the Windows GUI.

Executive ServicesExecutive 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.

ReviewReview

Microsoft Windows Operating System

Windows NT Architecture Overview