Few network operating system releases promise as many features or as much functionality in a single upgrade as Windows NT Server 5.0Currently in an early beta release, the next version of Windows NT Server (NTS), which is expected to ship sometime next year, will deliver a more scalable network services infrastructure and distributed applications platform for enterprise environments than its predecessor.
Some of Version 5.0's new features, such as a scalable, hierarchical directory service, are an attempt to catch up to competing products such as Novell's IntranetWare. However, many of NT's other enhancements will help the NOS stand out as an unrivalled platform for distributed enterprise applications.
Perhaps the most anticipated component in NTS 5.0 is Active Directory, an enterprise-level directory service infrastructure. Active Directory's "namespace", which consists of the directory's organisational schema and conventions for naming, defining, and accessing directory objects, borrows heavily from both X.500 and the Internet's DNS.
In addition, Active Directory relies on the DNS protocol to locate instances of the directory and Lightweight Directory Access Protocol (LDAP) 3.0 for native query access to the directory's objects.
This means that TCP/IP will be the default protocol for NTS 5.0 and that NetBIOS resolution services, such as the Windows Internet Naming Service (WINS) found in previous versions of NT, will no longer be required in pure NTS 5.0 environments.
However, to ensure backward-compatibility, Microsoft will continue to support WINS and various legacy protocols, such as NetBEUI.
Active Directory also lets you extend the directory to support new objects and supports directory-enabled applications (such as e-mail) through Microsoft's Active Directory Services Interface tool or the LDAP C-API.
With Active Directory, NT domains and domain trusts take on a more complex form. Each NTS 5.0 domain hosts its own directory, giving you more control to delegate administrative authority. For example, unlike with NT 4.0, you can now assign specific administrative authority over individual users or a group of users.
In addition, NTS 5.0 domains use multimaster replication to promote high availability of the directory and help distribute administration across the enterprise.
With multimaster replication, each domain controller holds a master replica of the domain directory. Multimaster replication lets you distribute administration to any NTS 5.0 domain controller, and any such changes to the directory are automatically replicated to the other domain controller servers.
Multimaster replication eliminates the Primary Domain Controller and Backup Domain Controller roles currently implemented in NT 4.0. For those shops migrating from previous NT products, NTS 5.0 will disable multimaster replication if it finds any older domain controllers residing within the domain. (Unfortunately, tools for scheduling efficient directory replication over WAN links weren't available in this beta release.)NTS 5.0 will allow administrators to link various domains into a hierarchical domain structure similar to that used in DNS, resulting in fairly scalable, globally distributed architecture. For example, the NTS domain arn.com could be an organisational "parent" to other NTS domains, such as nz.arn.com and asia.infoworld.com. In turn, each subordinate domain could parent additional domains, such as editorial.asia.infoworld.com and sales.nz.arn.com.
NTS 5.0's capability to link domains also allows for transitive trusts between domains. In previous NT versions, administrators had to explicitly define bidirectional trust relationships between all domains in the enterprise, resulting in an unmanageable administrative nightmare for any large deployment.
With transitive trusts, though, administrators can define a single trust relationship between two NTS 5.0 domains, and any subordinate domains in the hierarchy will implicitly inherit trust relationships as well. Transitive trusts should serve to reduce some, but not all, of the domain complexity headache.
In conjunction with Active Directory, NTS 5.0 uses the Kerberos Version 5 private-key security implementation as the primary method of security. However, NTS 5.0 will continue to support third-party security providers and remain backward-compatible with the current NT LAN Manager security implementation.
NTS 5.0 also includes Microsoft Certificate Server for issuing and managing x.509 certificates. And administrators will be able to map x.509 certificates to directory user accounts. This gives NTS 5.0 an edge over rival NOSs, allowing secure access to information resources over the Internet and between business partners.
NTS 5.0 is expected to include a number of features that will make the platform a more robust distributed application server, including Internet Information Server 4.0, Microsoft Transaction Server, and Microsoft Message Queue Server. However, none of these components were integrated in the beta release.
One of the more exciting features of NTS 5.0 is the application management feature, which is a component of Microsoft's Zero Administration Windows (ZAW) initiative. The application-management feature leverages the Active Directory to let administrators publish or assign applications to users at the domain or organisational-unit levels of the directory.
Although I was impressed with the application management capability, I was disappointed that the scope of assigning an application isn't more granular. For example, I could assign or publish an application only to an entire domain or to an organisational unit and not to specific users or groups. In addition, if a newer version of an application is installed on a system, the older version is automatically overwritten, leaving no recourse if a different user requires the older version of the application.
Another ZAW-related feature not yet implemented but expected in the final release is IntelliMirroring, which replicates user and application data at both the client and the server. This enables redundant data storage and simplified desktop hardware replacement.
NTS 5.0 will support all of the forthcoming planned enhancements for NT Workstation. But in some cases, the NOS will provide more support. For example, NTS will support I2O and hierarchical storage management.
Also, only NTS 5.0 will offer 64-bit Very Large Memory support, allowing the NOS to support as much as 32Gb of RAM on Digital Alpha platforms. Finally, NTS 5.0 will include Microsoft Distributed file system technology, which lets you combine disparate network-bound volumes into a single, logical network volume or share.
NTS 5.0 promises to be a much more competitive and viable NOS solution for large enterprise settings. And, by including such key components as Transaction Server and Message Queue Server into the base OS, NTS will provide an excellent architectural platform for quickly building and deploying distributed applications.
The bottom line: Windows NT Server 5.0, betaPros: Active Directory; Kerberos; Version 5; security; integrated Internet Information Server 4.0, Transaction Server; Certificate Server; and Distributed file system; integrated support for x.509 certificate mapping; hierarchical storage management; I2O; application distribution and managementCons: Fairly unpolished beta release; lacks key features promised for final versionPlatform: Minimum requirement: Intel Pentium/133 (or higher) with 24Mb of RAM (64Mb of RAM recommended) or Digital Alpha with 32Mb of RAMShip date: 1998.