By John Ruley, Editor-at-Large

FROM THE BEGINNING, Windows NT was different-a 32-bit system praised for its security, scalability and portability, but still just a little too much operating system for the average user. Yet over the past three years, both the desktop and server versions have experienced explosive growth. Although Microsoft won't release figures for NT's installed base, we estimate it to be 2 million to 4 million.

Could NT really replace Windows 95 as the operating system of choice for both servers (with NT Server) and desktops (with NT Workstation)? Microsoft is sure that both Windows 95 and NT have a secure future until at least 1999. But, come the new millennium, don't be surprised if a new operating system rules your desktop.

NT 4.0 is definitely not Cairo. Core features planned for that massive NT update include object-oriented additions to the NT file system, a new distributed security model derived from MIT's Kerberos project and PnP support. None of these is included in NT 4.0.

One additional feature originally planned for 4.0 has been dropped: a one-time Win95 upgrade feature Microsoft said was supposed to migrate "around 100 of the most popular Win95 applications." This was more difficult than originally anticipated and won't be available until Cairo ships. In the meantime, you can run both NT and Win95 on the same system, but doing so requires separate installations-including duplicate installations of the applications you use on both systems. This is necessary because NT and Win95 don't share the same Registry data.

NT's system requirements remain lofty for consumers: a 486 or better CPU (Microsoft has dropped all support for 386 processors in this release) with at least 12MB of RAM and 108MB of hard disk space for NT Workstation. Although our tests indicate NT runs under 16MB of RAM, we recommend twice the minimum-24MB of RAM and at least 216MB of free disk space. You can run NT in a smaller system, but you won't be happy with the performance.

Read the release notes before you install NT 4.0, even if you have experience with past versions. Beyond the change to NT's video architecture (which renders pre-4.0 video drivers obsolete), there are numerous changes to NT setup that can cause you serious trouble. Here are some examples: All support for the OS/2-compatible High Performance File System (HPFS) has been dropped. Support for a half-dozen older (8-bit) SCSI adapters has been moved from the base NT installation to a driver library. If you have one of those adapters, you must create a driver diskette before you install. Access to a CD-ROM, directly or over a network, is now required to set up NT-the diskette-based setup has been dropped, as has support for 5.25-inch floppy disks.

If you've experimented with the Shell Technology Preview (STP) add-on to NT 3.51, you must remove it before you upgrade to NT 4.0. When you upgrade, you don't automatically get your STP Start menu and Desktop settings (the release notes provide instructions for recovering them manually).

We tested NT 4.0 Workstation (beta 2, build 1314) on various desktop systems ranging from a Zenith Z-Noteflex 486/75 notebook with 16MB of RAM, up to a Digital Venturis Pentium Pro-based system with 32MB of RAM. Although NT worked on all systems, we encountered problems upgrading from NT 3.51 on several of them.

In each case, we traced the problem either to failure to follow the release notes' detailed instructions or failure to update a third-party driver during setup. Based on this experience, we recommend you carefully inspect your system setup before you upgrade. If you're using any third-party drivers, don't assume they'll work with NT 4.0. Check with the vendor to see if an updated driver is available before you attempt to upgrade.

Certain applications also require an upgrade because of changes in an NT subsystem. In particular, most remote-control applications won't work because of an NT video-architecture change. And fax applications that combine a 32-bit server and a 16-bit client will be affected by the change in NT's print spooler. Some third-party network redirectors won't work either.

Once we got past the installation problems, everything worked fine. Except for the aforementioned application categories, all our applications appear to be working.

With all the attention being paid to NT 4.0's new user interface and other end-user features, what could Microsoft possibly add for network managers and server administrators? Actually, quite a bit. NT 4.0 represents as significant an upgrade on servers as it does on desktops.

We tested NT Server 4.0 (beta 2, build 1314) on a variety of single- and dual-processor Intel systems, as well as on a Mips Technologies RISC-based system. It was generally stable, and most features worked well. The few exceptions were mainly in cases where new features were not completely stable (or in one case, even available for hands-on evaluation) in beta 2.

NT Server is not a lightweight operating system. Microsoft's published requirements are a 486 or better CPU with 16MB of RAM and at least 148MB of contiguous free disk space. We found these minimums were inadequate for all but the most casual user. Realistic requirements for a light- to moderate-duty server are 32MB of RAM and at least 1GB of hard disk space, depending on how many users you intend to support.

NT Server 4.0 has the same Win95-derived look and feel as NT Workstation 4.0. Although some administrators will resist the change, this move restores the "single UI across platforms" that was originally one of NT's great strengths. Administrators in an environment with Win95 or NT clients (or a mix of both) live and work in the same UI as their users.

Aside from the overall look and feel, the UI doesn't significantly change the way administrators work. NT Server still has the same basic administration tool set. User Manager for Domains, Server Manager, Disk Administrator, Event Viewer, Performance Monitor, DHCP Manager, WINS Manager, Network Client Administrator, License Manager and the Migration Tool for NetWare are essentially unchanged. Remote Access Administrator is also the same, but it's now part of the Administrative Tools menu, rather than having a separate folder. A new System Policy Editor, compatible with both NT and Win95, replaces the old User Profile Editor from NT Server 3.x. Four additions in 4.0 include Administrative Wizards, the System Policy Editor, an enhanced Windows NT Diagnostics Tool and Network Monitor (a software "sniffer" previously provided only with Microsoft's Systems Management Server).

Of these, the Administrative Wizards represent the most significant change. From an opening screen called Getting Started with Windows NT Server, the wizards provide simple step-by-step procedures for adding user accounts, managing administrative groups, controlling file/ folder access, adding print drivers, adding and removing programs, installing modems, creating network client installation disk sets and managing license compliance. This may help appease you if you feel NT's administrative tools, while graphical, could be easier to use.

Still, the wizards don't go nearly far enough. For instance, there's no wizard to change your account name, or to move your account from one domain to another-procedures that drive NT administrators to distraction because they have to delete the old account and create a new one.

The new versions retain NT Server 3.51's two licensing modes: per-user licensing and concurrent connection licensing. The former requires an access license for each user who will connect, but the license allows connection to any number of systems. The latter licenses a server for a specific number of users.

One feature that applies to both NT Workstation and Server will please network managers and administrators. For the first time, Microsoft is providing setup tools that allow an NT system to be completely preconfigured without human intervention-from video and network settings to preloaded applications. This is accomplished with a combination of tools: Windows NT setup provides an unattended mode option that lets you associate a response file containing answers to the selections users normally make during setup. In 4.0 this functionality is expanded by providing uniqueness database files (UDFs) and allowing you to add third-party installation scripts in a $OEM$ subdirectory of the setup directory tree.

For the extreme case where you can't set up an app through a script, a new SYSDIFF. EXE tool lets you take a "snapshot" of a standard setup and use it to generate a "difference file" that describes all files and Registry settings needed to fully install an application. NT Setup can then be customized to replay the difference file-copying all necessary files and making all necessary Registry settings automatically-when executed on a target system. For large organizations and OEMs, this will be a tremendous time-saver.

Like Workstation 4.0, the NT Server beta build (1314) we tested wasn't fully performance-tuned. Again, we can confirm improvements in video performance (though this is of questionable value on a server). Beyond that, Microsoft claims that network transport interface improvements have significantly boosted performance on fast Ethernet. Other sources tell us that what this really amounts to is relaxation of a bug that prevented NT 3.x from fully exploiting fast Ethernet. There's also a print spooler functionality change that improves client response by off-loading page rendering to the server.

We experienced our share of bugs while testing NT Server 4.0, which is to be expected with a beta. Aside from the problems with third-party drivers and applications already mentioned, we found that a particularly frustrating bug-or the lack of adequate documentation-prevented us from fully testing PPTP. We could get a connection and use low-level IP utilities like ping and ftp, but any attempt to view shared files and printers failed. We found documentation for many new features-in particular, the built-in multi-protocol routing and IP security-to be completely inadequate. The IP security dialog and associated less-than-helpful help in this beta will be good candidates for our Useless Dialog o' the Month if they aren't fixed before NT 4.0 ships.

Again, be sure to review the release notes before attempting an installation. This is a major upgrade, and the changes from past versions are significant. The Windows NT evaluation and migration planning CD-ROM, which should be available from Microsoft for a nominal charge (basically, shipping cost) by the time you read this, will prove helpful.

NT 4.0's combination of performance improvements, new features and a new user interface make it a compelling upgrade for NT 3.x users. Although it's still not for everyone, NT is increasingly becoming a mainstream system for high-end users.