Some of the main topics in this chapter are
Before the release of Windows NT Server 4.0, it was easy to know what components were included in the base operating system and what components were available as free or priced add-ons. In working on Windows NT Server 4.0, however, Microsoft got "Internet fever" and began to release a staggering number of upgrades and add-on components via the Microsoft Web page. Some of these components are free and some are trial versions of commercial products. In addition to Web-based components, Microsoft continues to sell a number of shrink-wrapped products for Windows NT Server--most notably the components included in the BackOffice suite (SQL Server, Exchange, and so on).
The net result of all the optional components and upgrades associated with Windows NT Server is confusion about what Windows NT Server components are available, where you get them, and how much they cost. With this in mind, this chapter explores the objects of Windows NT Server and the key features you find in it.
Windows NT is a complex operating system that required years to design and develop. Understanding the major design goals for Windows NT can help you understand not only how and why Windows NT works the way it does but also how to take advantage of the results of the design goals.
An extensible operating system is one that can be extended to include new features and enhance existing features. Extending the capabilities of some operating systems is a Herculean task, because the operating system is designed such that its components are so closely intertwined as to be inseparable. Modifying one part of such an operating system requires modifying other parts and often introduces unexpected and unwanted behavior.
Windows NT, on the other hand, has a very modular design. It uses a client/server model at its core, with subsystems such as security, I/O, and other basic functions carefully segregated into separate entities that interact with one another through message calls. Because of this, operating system components can be modified easily without affecting other components. If a new security feature is required, for example, only the security subsystem needs to be modified. The new security subsystem continues to interact with the rest of the operating system as before.
This modular design also means that new subsystems and their features can be added without affecting other subsystems, making it easy to extend the capabilities of the operating system.
Also figuring in the extensibility of Windows NT is the use of objects in the operating system. Objects are abstract data types used to represent various system resources. A section object, for example, is a region of shared memory. Objects are managed by the operating system and accessed by applications through standard object services, which consist of predefined API (Application Programming Interface) calls. Because objects place an abstraction "wrapper" around these data types, they can easily be changed without affecting other parts of the operating system. Thus, it's easy to modify existing object structures or add new objects to extend the capabilities of the operating system.
Also playing an important role in Windows NT's extensibility is the use of loadable drivers, which means that drivers can be added to the operating system dynamically even after the operating system is running. This enables support for new devices to be added easily to the operating system. Some device drivers, however, require that the system be restarted to function.
Lastly, the RPC (Remote Procedure Call) feature in Windows NT, which enables applications to call services independent of the location of those services, makes it possible for the operating system to access services provided by other computers on the network. These services can be made available at any time across the network, extending the capabilities of the operating system.
Another design goal for Windows NT was portability. A portable operating system is one that can be ported (translated) easily from one hardware platform to another. MS-DOS, for example, runs only on systems based on the Intel 80x86 architecture, limiting its appeal and market scope. Windows NT, on the other hand, runs on a variety of systems, including those based on the Intel and Alpha platforms. Because of the way Windows NT is designed, it can be easily ported to other hardware platforms, as well.
To achieve this level of portability, Windows NT had to be written in a portable language. Microsoft chose C as that language, because the C language is supported on a range of platforms and is not hardware-dependent. Programs (and operating systems) written in C can be ported to new platforms by recompiling the software for the new platform.
It isn't possible to write an operating system without relying on some hardware-specific code (setting registers is an example), so parts of the operating system must be very hardware-specific and nonportable. Hardware-specific code in Windows NT, such as the parts of the operating system written in assembly language (which is hardware-dependent), are carefully isolated and localized. By isolating and localizing this code, Windows NT's designers made it possible to more readily change that code and port the operating system to other platforms. The hardware-specific code can be modified to suit the new platform and the operating system recompiled to run on that platform.
At the time Windows NT was developed, many computer users still relied on MS-DOS programs, so the capability to run DOS programs under Windows NT was a design goal (though not a major goal). During that same time period, Windows 3.0 and 3.1 were building considerable popularity for 16-bit Windows-based applications (many sold by Microsoft), so Win16 compatibility was extremely important. Because it had initially developed OS/2, Microsoft also felt obligated to enable its customers to run OS/2 applications under Windows NT. Finally, to make Windows NT attractive to government users, Microsoft decided to build in compatibility for POSIX applications.
NOTE: POSIX (Portable Operating System Interface based on UNIX) refers to a set of interface standards that simplify moving applications from one platform to another.
The modular nature of Windows NT figured closely with its capability to run applications written for other operating systems. Compatibility was achieved by creating separate environment subsystems, each of which provided an environment in which these applications could run. You learn about the various subsystems in Chapter 2, "Inside the Technical Details."
The United States government categorizes computer security requirements for government installations into seven levels. To expand its market to government installations, Windows NT was designed to meet level C2 security requirements, which had the following criteria:
You'll find not only solid security in Windows NT but also a great deal of flexibility in how you apply that security.
Although to a large extent today's computers have outpaced the average user's need for speed, operating system and application performance are still vitally important. Many applications still tax the operating system and hardware's capabilities, even on the fastest platforms. Performance was an even bigger issue when Windows NT was designed because the hardware of the day was less capable.
Windows NT provides excellent performance for native Windows NT applications, outperforming Windows 3.x by a factor of two or more, depending on the application. But Windows NT also provides excellent performance for running Win16 and DOS applications.
Another important design requirement for Windows NT was that it be a reliable and robust operating system. The operating system itself had to be reliable and as bug-free as possible. The modular design helped ensure the operating system was reliable by isolating subsystems from one another--an errant program or subsystem might bring itself down but not affect others. By providing each subsystem and application its own memory address space, Windows NT further ensures reliability. Windows NT also provides robustness, using structured exception handling to process errors and ensure that those errors don't go undetected and are handled.
NOTE: When a Windows NT application crashes, it typically does not take others down with it. Applications running in the Win16 environment, however, are not protected as well and can still be affected by a misbehaving Win16 or DOS-based application.
When you install Windows NT Server 4.0, you end up with a system that can immediately function as a file and print server or a Web server and has the potential (and underlying foundation) to serve as an application server (but no applications are included). You also receive a number of services and utilities in support of these core functions. This book discusses all the significant components included with Windows NT Server. From a general perspective, however, the Windows NT Server components can be broken down into the following categories:
Microsoft releases fixes and minor upgrades to these components in the form of service packs. A service pack contains fixes or improvements to any or all of the Windows NT Server components. Service packs are cumulative; the most recent service pack contains all the fixes issued in previous service packs.
Historically, Microsoft used service packs as the sole means of issuing formal Windows NT fixes; however, the advent of Service Pack 2 (SP2) for Windows NT Server and Windows NT Workstation changed Microsoft's strategy significantly. SP2 was so seriously flawed that Microsoft was forced to issue a series of "hot fixes" to the pack. As a result of this experience, Microsoft instituted a new policy of beta testing all service packs before release, starting with Service Pack 3. See Appendix D, "Service Packs 1, 2, and 3," for more information.
For the most part, the Windows NT Server networking components deliver file and print services to a broad range of client systems and create a network environment that is relatively easy to administer. The key components that enable Windows NT Server to function in a network environment are the protocols it supports. The base Windows NT Server operating system supports the following protocols:
All the Windows NT Server protocols can operate over a variety of network connections. NT Server can, for example, function in a 10 Mbps Ethernet, 100 Mbps Ethernet, token-ring, FDDI, or ATM LAN/WAN environment. NT Server can also serve as a router between two or more physical networks via the Multi-Protocol Routing (MPR) facility. This facility is a set of protocol options and services that enable NT Server to act as a router for IPX, TCP/IP, and AppleTalk connectivity.
For remote connections, NT Server includes the Remote Access Service (RAS) to enable client systems to connect into an NT Server network by using a phone line or ISDN connection. A RAS connection can be used to transport NetBEUI, IPX, or TCP/IP traffic.
TCP/IP has clearly become the protocol of choice for new NT Server networks. Microsoft includes three key services with Windows NT Server 4.0 to support operation and administration of TCP/IP clients and servers:
Finally, NT Server includes protocol and RAS components for non-Windows NT Microsoft client operating systems. The Windows NT Server 4.0 CD includes protocol components for DOS, a RAS component for DOS, and a TCP/IP component for Windows for Workgroups. You can find RAS and protocol components for other client environments on Microsoft's Web site.
NT Server 4.0 was released at the onset of Microsoft's drive to produce Internet/intranet tools and services. Although the majority of Microsoft's Internet/intranet products were released after NT Server 4.0 was finalized, NT Server does include the key ingredient to launch an Internet/intranet server, the Internet Information Server (IIS). The Windows NT Server 4.0 CD includes version 2.0 of IIS and three core services:
Each of these services can be installed independently of the other services; however, they are all managed through the Internet Server Manager interface.
One additional service--Index Server--is regarded as part of IIS, but is not included on the CD. Index Server is an index and search facility that enables you to search through documents stored on a Web server through a Web-based query interface. You can download Index Server for free from the Microsoft Web site.
Another important free download is IIS version 3.0. IIS 3.0 includes new features for server-side scripting, client-side scripting, enhanced ActiveX support, and multimedia broadcasting (NetShow). Many of the new Internet-oriented Microsoft products for Windows NT Server (for example, the Microsoft Commercial Internet System and Internet Personalization Server components) require IIS 3.0.
The Windows NT Server 4.0 CD includes one additional Internet/intranet component--FrontPage version 1.1. FrontPage is a dual-purpose component that enables you to create and edit HTML documents for use in conjunction with the WWW server service of IIS and to view and manage the contents of Web sites in your network.
The editing capabilities of FrontPage 1.1 are serviceable, but the management facility has some serious security flaws--in particular, it demands you open up your Web servers to remote Administrator access. A revised version of FrontPage (version 2.0.2, or FrontPage 97) is now available; however, it's provided as a priced upgrade. The revised version of FrontPage not only addresses the security defects of the 1.1 version but also includes improvements to the Web page-editing capabilities.
The core file, print, and application sharing functions provided by Windows NT Server were designed to accommodate Microsoft clients (such as DOS, Windows, Windows for Workgroups, Windows 95, and Windows NT Workstation). The base operating system does, however, include components to facilitate connectivity to other types of systems. These components are:
NT Server also supports an additional priced Microsoft product for NetWare connectivity--NetWare File and Print Services. This product enables an NT Server system to appear as a Novell NetWare server to NetWare clients.
No formal, designated components are included to support UNIX or IBM mainframe-AS/400 interoperability--there are no "Services for UNIX" or "Gateway for IBM" services from which to choose. Instead, support for UNIX and IBM connectivity is provided through ancillary services and utilities:
As noted, Windows NT Server can be used as an applications server in a client/server or distributed application environment. Although Windows NT Server does not include any application components per se, it does include a framework for applications communication. Most communication falls into the area of InterProcess Communication (IPC). Windows NT Server supports seven styles of IPC:
In addition to the IPC style of communication, Windows NT Server accommodates a higher-level interface for database connectivity, Open DataBase Connectivity (ODBC). ODBC provides a SQL-like interface that applications can use to communicate remote databases. Client applications can use ODBC to communicate with Windows NT Server-based databases (such as SQL Server), and Windows NT Server can use ODBC to communicate with "foreign" databases (for example, DB/400 on an AS/400 or Oracle on an HP-UX system).
The administrative components of Windows NT Server enable you to effectively manage and monitor the deployment of Windows NT Server systems. One critical function in this area is the capability for a Windows NT Server to act as a Primary Domain Controller, Backup Domain Controller, or standalone (resource) server. When acting as a PDC, Windows NT Server provides a central source to authenticate users in the network. As the name implies, a BDC acts as live backup to a PDC and can assume the role of a PDC in the event of a PDC failure. PDC and BDC are integrated features of Windows NT Server; however, you must designate a system to be a PDC or BDC during the initial installation process--you can only convert a standalone server into a PDC or BDC by fully reinstalling Windows NT.
Windows NT Server includes a variety of utilities to watch and administer the Windows NT Server environment. The following mainstream administrative tools can manage the hosting server or another server in the network:
The Windows NT Server operating system also includes tools that are restricted to managing and monitoring the Windows NT Server system hosting them:
An additional IIS-based utility (available as a free download from Microsoft's Web page) can administer Windows NT Server over Internet/intranet connections. This utility enables you to access a server via a Web browser and monitor/manage a variety of information, including service status, event log contents, and more.
Finally, Windows NT Server includes two special-purpose administrative tools:
One final component available for free download is Microsoft's Distributed file system (Dfs). Dfs adds a layer of logical names on top of conventional server-based sharing, enabling you to create logical shares that span physical servers. Dfs also enables you to change physical servers without having to change the name of the logical share used by the client systems. Additional client-side software (also available for free download) is required to implement Dfs.
The previous sections have focused on the components that enable Windows NT Server to function as a server system. A Windows NT Server system can, however, also be used as a workstation; therefore Windows NT Server includes all of the same client-oriented components found in Windows NT Workstation. For example, Windows NT Server includes an audio CD player utility, a calculator, a text editor (Notepad), and many other workstation-oriented functions.
The bottom line is that Windows NT Server is a superset of Windows NT Workstation. For example, in addition to the software components discussed in this chapter, Windows NT Server also supports larger Symmetric Multi-Processor (SMP) configurations and more concurrent network connections (for example, RAS, IIS, and file server connections).
As noted, an out-of-the-box Windows NT Server system can be a file server, print server, and Web server--you simply plug it in and turn your clients loose on it. Although Windows NT Server can also be an application server, it does not come packaged with any applications. Because Microsoft intended Windows NT Server to be a commercial, enterprise-oriented solution, it developed additional products to augment the capabilities of Windows NT Server and foster application development and deployment on Windows NT Server. These products were then bundled to create the BackOffice suite of products. The original BackOffice suite (version 1.0) was a focused set of server-based programs designed to deliver classic IS functions:
The definition of the BackOffice suite blurred almost as soon as it was released. One critical component--Exchange--did not make it into the early suite packaging and had to be introduced to BackOffice at a later time, replacing MS Mail in the process. Then, just as the BackOffice suite began to settle down, the market demanded Web solutions. In response, Microsoft developed the Internet Information Server (IIS) and Microsoft Proxy Server and introduced them to the BackOffice suite.
As a result of these changes, the present BackOffice suite (version 2.5) includes:
You can purchase the entire BackOffice suite, or you can purchase the individual products.
Although the previous list of products is the official list of components that make up the BackOffice "suite," they are only part of the entire BackOffice "family," which embraces the following additional Internet-related Microsoft components that are sold on an individual basis:
News Server News Server implements the Network News Transfer Protocol (NNTP) within IIS. News Server can be used to offer both public and private forums (newsgroups) to a wide variety of client programs, including the newsreader components in the IE 3.0 and Netscape 3.0 browsers.
Mail Server Mail Server is a POP3/SMTP mail server. Mail Server is provided as an alternative mail system for those users who don't want or need the combined mail/groupware capabilities of Exchange.
Internet Locator Service(ILS) ILS provides an online database of user information (name, address, phone, and so on) and, more important, maintains dynamic information about when a user is online (the IP address currently in use). The dynamic information is used by client-side programs such as Microsoft's NetMeeting, an Internet-based group conferencing system.
Internet Personalization System (IPS) IPS enables you to keep information about Web visitors so you can personalize Web page contents or Web site flow based on their personal preferences.
Microsoft Membership System (MMS) MMS provides a user authentication system built around service tiers (such as free, paid, premier, and so on). MMS works in conjunction with the standard Windows NT security system, but is geared for Web usage.
Content Replication System (CRS) CRS replicates HTML documents and related files from one Web server to additional (one or more) Web servers. CRS provides a simple means to maintain multiple Web sites with identical content.
While bringing these products to market, Microsoft has changed the names and bundling options for these products more than once. For example, at one point, the Merchant Server was part of the Commercial Internet System, but it was later moved out. Keep this in mind as you look at what is available to you now. Some of the bundled products might now be unbundled, and some of the unbundled ones might now be bundled. Fortunately, the primary function of each component is not subject to change.
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