The electronic mailbag got pretty full after my column on the Microsoft/Justice Department controversy. (See “The Justice Department’s action on Microsoft has everyone missing the point,” April 20, page 104.) Most letters were complimentary. A few pointed out that since Microsoft has a “noncoercive” monopoly it will eventually fail without government intervention. Their conclusion: Keep government out of it.

Well, OK. In fact, since muggers eventually die of old age, I guess we don’t need to prosecute them either.

Some readers thought I wanted to prevent Microsoft from integrating Internet Explorer into its future operating systems. Heck, it can build it into Hydra for all I care (just what you’d want, too: a Windows desktop accessing a server-based browser –- the ultimate “stupid client architecture”).

But no matter how much Microsoft sings, dances, and plays the tuba, Internet Explorer isn’t part of the Windows 95 or Windows NT 4.0 operating systems.

The biggest question on everyone’s mind, though, is whether Microsoft really has a monopoly in desktop operating systems. Since this hits you where you live, let’s take a close look. Do you have any real alternatives to Windows?

If you’re the CIO for a typical company, you’re establishing an architecture, not buying stand-alone PCs, so you probably have these requirements:

1. A quality word processor, electronic spreadsheet, end-user database, e-mail client, and Internet browser for general users. You’d prefer Microsoft Office since that’s the format used by most of your business partners.

2. A platform for commercial client/server business applications (accounting, payroll, inventory, or a whole enterprise resource planning system). You need a platform most vendors build for.

3. A platform for which you can develop and deploy in-house client/server business applications. Typical in-house applications have to last a decade or two, so future support is critical. And this OS has to match the OS that fits requirement No. 2 since you’ll need to run both in-house and commercial applications on the same desktops.

4. If the OS that satisfies requirements No. 2 and No. 3 isn’t the OS for general users, it has to support the same office suite or you can’t share files electronically. (No, “Save as .rtf” isn’t good enough.)

Quality engineering doesn’t make the list as a requirement.

An OS that satisfies all requirements can be the company standard. An OS that satisfies No. 1 and No. 4 can participate in a mixed architecture. Other OSes may run on some desktops, but only for specialty uses.

Windows passes all the tests. How about the alternatives: Unix, OS/2, and Macintosh?

Unix fails requirement No. 2, so you can only use it in a mixed architecture. And no Unix satisfies requirement No. 4. Scratch Unix.

OS/2? With SmartSuite OS/2 partially satisfies No. 1 and fully satisfies No. 4. It fails No. 2, though –- few manufacturers of business software create OS/2 clients anymore –- and as a result, No. 3 as well. You can use OS/2 except where you need to deploy client/server applications.

How about the Mac? With Microsoft Office it satisfies requirements No. 1 and No. 4 nicely.

The Mac, however, fails dismally on requirements No. 2 and No. 3. So although you can use Macs in a mixed environment, you can’t make them the standard, only a niche participant in your architecture.

Then there are the intangibles, like availability of suppliers, support, and programming talent. All of these make Windows more attractive than its competitors.

So here are your options: Use Macintoshes for general-purpose desktops and Windows for those running business applications, or use Windows for everything and save yourself the headaches of a mixed environment.

A judge and jury will have to decide if, for desktop operating systems, Windows fits the legal definition of monopoly.

Do you, as a typical CIO, have a realistic desktop operating system alternative today? The answer is pretty clear, even if you don’t like it.