A giant leap for Windows

We are just one week away from the launch of Microsoft's newest operating system. Unlike the two Windows 98 releases of the past 18 months, Windows 2000 is a more substantial evolution of the NT line, one almost as big as the jump from NT 3.51 to NT 4.

For many users, this won't come a moment too soon. NT 4 was offered as a robust, highly scalable, secure operating system, but it wasn't able to deliver. It has caused no end of irritation for administrators, and has created support costs for companies forced to roll out as many as five service packs to workstations while trying to service a user base continually frustrated by the platform's instability.

Microsoft assures us this will change. From my work with the alpha and beta releases of 2000, I'm inclined to agree. The company achieved a significant milestone with the beta 3 release of 2000, which in head-to-head usage tests surpassed the release version of NT 4 in terms of stability and ease of use.

Since that point, 2000 has set new standards for Windows-based network operating systems within Microsoft.

So what does 2000 bring to business that is so revolutionary that companies should consider migrating or upgrading their existing Windows network?For some, Windows 2000 will offer little to justify the cost or disruption that an upgrade will undoubtedly bring. But, in many cases, the new features will justify an upgrade through the time savings and collaborative working arrangements they will introduce into the working environment.

The most notable of these is Active Directory, the main new feature of Windows 2000 and one that lies at the heart of the operating system.

Active Directory
Active Directory is Microsoft's attempt at a directory service to rival Novell's NDS.

The Windows 2000 server directory service hierarchically stores information about network objects and makes this information available to administrators, users and applications. Using Active Directory, the network and its objects are organised by constructs such as domains, trees and forests, trust relationships, organisational units and sites.

Active Directory is based on standard directory access protocols, such as lightweight directory access protocol. It can interoperate with other directory services, employing these protocols. Several application programming interfaces, such as active directory service interfaces, give developers access to these protocols, allowing them to incorporate hooks from third-party applications into the Active Directory service.

But what use is this to you? A directory service gives you a shared repository for user information and a shared access port for management applications and compatible applications, things that can use the information already stored in the directory structure for its own needs.

Think of a Windows directory as a piece of a hierarchical structure (either within another directory or as a root or main directory) that stores information about objects on the network.

Objects include shared resources such as servers, shared volumes and printers; network user and computer user accounts; as well as domains, applications, services, security policies and just about everything else in your network. One example of the specific kinds of information a network directory might store about a particular type of object is a user's name, password, email address and phone number as part of a user account record.

A directory service differs from a directory in that it combines both the directory information source and the services, making the information available and usable to administrators, users, network services and applications.

Ideally, a directory service makes the physical network topology and protocols completely transparent to the user so that a user can access any resource without knowing where or how it is connected to the rest of the network.

To continue the user account example, it is the directory service that lets other authorised users on the same network access stored directory information (such as an email address) about the user account object.

Directory services can support a variety of capabilities. Some directory services are integrated with an operating system, and others are applications such as email directories. Operating system directory services such as Active Directory provide user, computer and shared resource management. Directory services that handle email, such as the upcoming Microsoft Exchange 2000, enable users to look up other users' details and send email.

As well as providing a place to store data and services to make that data available, Active Directory simplifies the process of protecting network objects from unauthorised access and replicates objects across a network so that data is not lost if one domain controller fails.

Active Directory includes one or more domains, each with one or more domain controllers, enabling users to easily scale the directory. Multiple domains can be combined into a domain tree and multiple domain trees can be combined into a forest. In the simplest structure, a single-domain network is simultaneously a single tree and a single forest.

Com+
Sadly, too many people confuse Com+ with Com, thinking the former is the direct successor to the latter. This isn't strictly accurate. In Windows NT 4, Com and MTS were implemented to make developing distributed applications easier. In Windows 2000, Com+ is a close combination of the pair.

Com+ unifies the programming models inherent in Com and MTS services. It also merges the infrastructure code for working with components and the security model previously supplied by MTS. This makes it easier to develop distributed applications by reducing the work associated with developing, debugging, deploying and maintaining an application that previously relied on Com for certain services and MTS for others.

Components written using the Com model will work with Com+. Com+ also extends the Windows platform support for attribute-based programming, which allows components to be used in a more flexible manner. Com+ provides services that are used from any compatible programming language or tool, allowing more interoperability between components. It does this by defining a standard set of components and making all components self-describing.

This ensures that all Com+-compliant system services and components will be accessible to all Com+-aware languages, in addition to simplifying the deployment of components and applications that use them.

Com+ also offers a function called Com+ Events, which uses a multicasting publish/subscribe event mechanism to allow multiple clients to subscribe to events published by various servers. The Com+ Events system maintains an event database with information about various events, publishers, subscribers and individual subscriptions to enable this.

Plug-and-Play
One area in which NT 4 suffered was its poor implementation of the Plug-and-Play protocol, the service first introduced with Windows 95 that allows the operating system to dynamically assign drivers to new hardware upon insertion. Plug-and-Play support has been overhauled. A native Plug-and-Play implementation was integrated into the existing Windows code base and includes the following:

• Windows 2000 now performs automatic and dynamic recognition of hardware. This includes initial system installation, recognition of Plug-and-Play hardware changes between system boots and response to run-time hardware events, such as dock or undock and device insertion or removal.
• Drivers for Plug-and-Play devices do not assign their own resources. The required resources for a device are identified only when the device is enumerated by the operating system. The Plug-and-Play Manager retrieves the requirements for each device during resource allocation. Based on the resource requests that each device makes, the Plug-and-Play Manager assigns the appropriate hardware resources, such as I/O ports, IRQs, DMA channels and memory locations. The Plug-and-Play Manager reconfigures resource assignments dynamically when needed, such as when a device is added to the system, and requests resources that are already in use.
• Windows now automatically handles the loading of appropriate drivers. Previously, drivers had to be added manually in the first instance.
• Power management handling Dynamic events, such as the addition or removal of a device or wake up on event, (such as a modem ringing) are now more widely supported.

Windows 2000 supports legacy Windows NT drivers, but these will still have no Plug-and-Play and power management functionality. To take advantage of these features, manufacturers will need to develop separate new drivers that integrate the latest Plug-and-Play and power management functionality for use under Windows 2000.

More importantly, Windows 2000 now has full native support for the Universal Serial Bus (USB) interface.

Clustering
Windows 2000 boasts a new cluster service, enabling the connecting of multiple servers into server clusters that provide easy manageability of data and programs running within the cluster. Cluster service has three principal advantages:

• Improved availability by enabling services and applications in the server cluster to continue providing service during hardware or software downtime.

• Increased scalability by supporting servers that can be expanded with the addition of multiple processors (up to a maximum of eight processors in Windows 2000 Advanced Server and 32 processors in Datacenter Server), and additional memory (up to a maximum of 8Gb of Ram in Advanced Server and 64Gb in Datacenter Server).
• Improved manageability by enabling administrators to manage devices and resources within the entire cluster as if they were managing a single computer.
• Cluster Service still uses the standard Windows 2000 and NT server drivers for local storage devices and media connections. Cluster Service supports several connection media for the external common devices that need to be accessible by all servers in the cluster. External storage devices that are common to the cluster require SCSI devices and support standard PCI-based SCSI connections as well as SCSI over fibre channel and SCSI bus with multiple initiators. Fibre connections are SCSI devices, simply hosted on a fibre channel bus instead of a SCSI bus. Conceptually, fibre channel technology encapsulates SCSI commands within the fibre channel making it possible to use the SCSI commands that Cluster Service is designed to support. These commands are reserve/release-based and bus reset-based and will function the same over standard or non-fibre SCSI interconnect media. Windows 2000 Datacenter Server also supports four-node clusters and requires device connections using Fibre Channel.

One of the benefits of Cluster Service is that applications and services running on a server cluster can be exposed to users and workstations as virtual servers. To users and clients, connecting to an application or service running as a clustered virtual server is transparent. Any node in the cluster can host the connection to a virtual server. The user or client application will not know which node is actually hosting the virtual server.

In the event of an application or server failure, Cluster Service moves the entire virtual server resource group to another node in the cluster. When such a failure occurs, the client will detect a failure in its session with the application and attempt to reconnect in exactly the same manner as the original connection. It will be able to do this successfully, because Cluster Service maps the published IP address of the virtual server to a surviving node in the cluster during recovery operations. The client session can re-establish the connection to the application without needing to know that the application is now physically hosted on a different node in the cluster.

Windows as a mobile platform
Laptops have remained one of the few resources in a company that do not migrate happily to NT. The platform has never been comfortable with PCMCIA, power management or interchangeable drives, and so people have continued to use Windows 9x on their laptops. Those brave enough to use NT on their portables have found it necessary to reinstall drivers after reinsertion of a device. Windows 2000 takes steps to rectify this with wide-ranging hardware and standards support.

The entire driver database is now stored on the system at initial installation, so there is no need to keep your system CDs with you at all times. The improved Plug-and-Play support has been extended to the PCMCIA interface, although there are still issues with wake-up on event support with many devices, particularly modems.

Improved power management support means that Windows 2000 can now manage the power consumption of your laptop, as well as supporting suspend and hibernation modes natively.

Windows 2000 is more than just an upgrade to the NT line of operating systems. But how it performs in a real-world environment remains to be seen.