Now that the merits of 32-bit operating system technology are apparent, the next logical step is to look at products on the market today and examine the relative merits of each. Currently there are three major 32-bit platforms available for the Intel CPU architecture: OS/2, Windows NT, and the numerous flavors of the UNIX operating system. UNIX and Windows NT are portable to other CPU platforms, as will be the microkernel version of OS/2 (based on IBM's Workplace software technology) that is being designed for the PowerPC.
A seasoned veteran, Operating System/2 (OS/2) is in its third generation and offers a number of advanced features found nowhere else on the Intel platform. These include an advanced, object- oriented interface (the Workplace Shell); a comprehensive object model (the System Object Model, or SOM); excellent backward compatibility with DOS and Windows applications; and the most reasonable resource requirements of any full-fledged 32-bit OS.
OS/2's Workplace Shell (WPS) is the crown-jewel of the product's many features. Using an easily mastered desktop metaphor, WPS insulates users from the complexities of the underlying system software. Most file and application-related functions are a simple drag-and-drop affair, and navigating both local and network file systems is made easier by an intuitive, "file folders" interface.
But ease of use is not the heart of WPS, merely a side-effect of OS/2's robust SOM. With SOM, OS/2 is capable of tracking thousands of individual objects, be they file system objects, desktop icons, or hardware devices. And this tracking capability also applies to links between objects. Few interface elements are static in WPS -- if you make a change to an object (for example, renaming a folder), you can be sure that any affected references will be updated automatically.
Backward compatibility with DOS and Windows applications is another of OS/2's strong points. OS/2's Virtual DOS Machine (VDM) support is viewed by many to be better than DOS itself -- you can create individual CONFIG.SYS and AUTOEXEC.BAT files for each VDM, and OS/2's preemptive multitasking makes juggling multiple concurrent activities a piece of cake. Win-OS2, OS/2's Windows 3.1 application environment, also offers functionality above and beyond its native cousin. For example, you can isolate applications in their own private Win-OS2 "sessions," and these in turn can be preemptively multitasked alongside other OS/2, DOS, and Windows applications.
If OS/2 has a downside it's lack of hardware device support. But the situation is improving with OS/2 Warp.
Where NT falls short as a desktop 32-bit OS, however, is in the area of backward compatibility. While most 16-bit Windows productivity applications run properly under NT's WOW (Win16 on Win32) environment, the operating system's security and protection models prohibit the use of 16-bit device drivers. This severely limits NT's ability to support input/output-related applications like facsimile or host-connectivity; for these you need native NT software -- something that's all too scarce.
NT is also big. Though the latest version -- Windows NT 3.5 -- is slimmer than its earlier incarnations, it's still a hefty OS with a minimum RAM requirement of 12 MB; frankly, 16 MB is more realistic. Then there's the interface -- Windows NT retains the antiquated Windows 3.1 Program Manager/File Manager look and feel, making it a far less intuitive environment than the WPS-equipped OS/2.
Finally, Windows NT lacks an underlying SOM. Microsoft is promising such a model -- including a distributed, object-oriented file system -- for the next generation of NT, code-named "Cairo." But Cairo isn't due out until sometime late in 1995 or early 1996, leaving NT competing against far better-equipped competitors.
Where NT makes the most sense is as a back-end database or application server. The product's SMP support allows it to scale well as additional CPUs are introduced, while its fault-tolerant, transaction-based file system (NTFS) makes even complex server crashes relatively easy to recover from.
The UNIX operating system market is extremely diverse, with a myriad of choices for the Intel platform. As a result, it's necessary to use broad terms when referring to its member constituents. In many ways UNIX is the "old pro" of operating systems. Having originated in the 1960s on minicomputers and mainframes, its strengths are a fundamentally sound architecture, excellent portability (as evidenced by its presence on nearly every CPU platform around), and inherent networking capabilities.
Perhaps the biggest attraction to UNIX is the sheer number of implementations on the market. There is literally a flavor of UNIX available for every major CPU architecture, from high-end workstations to a simple Intel 486 PC. When a new CPU comes out, the first priority for the vendor is often to get a UNIX variant up and running as soon as possible. This, in turn, translates into a broad selection of potential hardware platforms, including most non-Intel RISC architectures, for the UNIX user.
Unfortunately, UNIX's proliferation has also been a curse in that it has lead to few viable, shrink-wrapped applications. Though the operating system itself is highly portable from CPU to CPU, there are many cases where a UNIX application written for one flavor of the OS will fail to run properly on another flavor -- even when the underlying hardware is identical.
The lack of true standardization in the UNIX API arena has relegated this powerful, if somewhat dated, operating system to the role of database server or high-end workstation environment. While these are not typical desktop PC operating system roles, they do highlight UNIX's other main strength: networking support. UNIX is inherently networkable, with extensive support for TCP/IP and distributed file systems like NFS from Sun Microsystems.