Section 10.1. Windows NT 4.0 | Inside Windows Storage: Server Storage Technologies for Windows 2000, Windows Server 2003 and Beyond

10.1 Windows NT 4.0

Windows NT 4.0 was positioned primarily as a file-and-print server and as an application platform, albeit one that happened to have some features conducive to SANs. This is apparent in light of the vast advances in storage features that Windows 2000 made over Windows NT 4.0.

The significant features of Windows NT 4.0 as they relate to storage are described in Sections 10.1.1 through 10.1.4.

10.1.1 Improved Storage Unit Accessibility

Windows NT 4.0 Service Pack 5 introduced support for a feature called Large LUNs, whereby Windows NT 4.0 supported up to 255 LUNs per SCSI target. Prior to this service pack, Windows NT supported only eight LUNS per target device.

10.1.2 CIFS, NFS, NetWare, and Macintosh Client Support

Windows NT 4.0 served as a good network-attached storage device because it could readily act as a file-and-print server to a wide variety of clients, including Windows clients running the SMB or CIFS network file-sharing protocol, various UNIX clients running the NFS protocol, NetWare clients, and Macintosh clients .

10.1.3 Defragmentation APIs

Windows NT 4.0 introduced defragmentation APIs that allowed independent software vendors (ISVs) to write defragmentation applications. As a result, ISVs could write applications that stood a better chance of working well and continuing to work well with future Windows NT versions and service packs . These APIs were designed in close consultation with ISVs to meet their needs.

10.1.4 Distributed File System

Dfs allows IT administrators to have a naming hierarchy that reflects the corporate organizational structure and do away with requiring users to track server names and file locations. Dfs also supports a heterogeneous operating environment in which servers running other operating systems besides Windows can also participate. In other words, Dfs provides a way to organize and manage network shares, much as a file system provides a way to organize and manage files.

A Windows client communicates with a Dfs server using CIFS, but once the client has obtained a referral to the actual server where a file is stored, it can connect to that server using another protocol, such as NFS or NCP (Network Control Protocol). This means that a single Windows NT server acting as a Dfs server can extend the benefits of Dfs to heterogeneous servers as well. Dfs uses File Replication Service functionality. The mappings between the physical location of a file and its logical path as accessed by a client are stored in the registry.

The advantages of using Dfs are

Ease of administration, because server shares can be moved around without user access being affected. Users access a resource that administrators can remap to point to a different server or server share.
Ease of use, because users are provided with an abstraction that does not require them to track physical storage associated with files.

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