DON'T TRUST ANY generalization -- including this one.
It's good advice, and I should remember it before I indulge in grandiose pronouncements, such as the one I made a few weeks ago when I declared that it doesn't matter what brand of IBM-compatible computer you buy today.
"Computers," I declared, "have become commodities. Hardware compatibility is no longer an issue. Anyone with a screwdriver can put together a workable IBM clone of decent quality."
This didn't sit well with Val S. Mrozek Jr., manager of computer and network technology at Davison Chemical Co. in Baltimore.
Davison is a division of the W.R. Grace & Co. empire, and Mrozek spends a goodly portion of his working hours trying to make computers in one fiefdom talk to computers in another.
People who engage in this thankless profession deserve some sort of sainthood. They often wind up buying industrial strength Maalox by the case.
In an anguished letter, Mrozek wrote, "I can assure you that all PC's are not created equal. I have run into situations where a 'compatible' worked until it was added to a network, at which time it did not work."
The magic word is "network," the agglomeration of hardware and software designed to let PCs talk to other PCs, let PCs talk to mainframes, and let mainframes talk to other mainframes.
Networks bring out the worst in personal computers. The well-behaved clone that runs Lotus and WordPerfect and drives a desktop laser printer flawlessly turns into a monster when somebody plugs in a Local Area Network (LAN) adapter board.
The problem today is that more and more businesses are installing networks to improve communications and "downsize" their huge systems by letting PCs take over a lot of the processing chores.
When I called Mrozek to talk about this, he regaled me with tales of woe in a company where the inhabitants of one province buy IBM machines from Computerland while others shop for computers at the bargain tables of local ham fests. Getting them to talk can be a nightmare.
"One of the worst cases we had was actually an IBM PC. It worked fine for a long time. But as soon as we put in a LAN adapter board and put it on the network, the keyboard stopped working. What we didn't know is that they'd bought a non-IBM keyboard for it. As soon as we put on an IBM keyboard, it worked fine.
"Somebody saved $30 when they bought that keyboard. But we had to send out tech support people at $20 or $30 an hour, and it took them two days to figure it out," he said.
Mrozek ran into another problem when a division bought third-party adapter boards that let P's emulate IBM 3270 terminals. This is the way many companies connect personal computers to their IBM mainframes.
One day, all the PCs stopped talking to the big computer. It took a while, but eventually Mrozek learned that IBM had changed some of the software on the mainframe side (this is what happens when you fix something that ain't broke to start with).
The new software worked fine with IBM's own equipment, but PCs with third-party adapter boards were out to a long lunch.
"We talked to [the vendor who made the boards] and they told us it would take weeks or months to make the fix," Mrozek said.
The problem with compatibility, Mrozek says, is that it's a "here-and-now" kind of thing. No one really knows what's on IBM's mind. It may put capabilities into its systems that go untapped for years. When IBM decides to use something it hasn't used before, the rest of the world shudders.
Another issue, Mrozek adds, is what happens when users try to switch to the new OS/2 operating system. Unlike DOS, the more-or-less generic operating system that runs most IBM-compatibles today, OS/2 is designed to run on a particular piece of hardware.
IBM sells its version of OS/2 for its machines, while other large manufacturers such as Compaq, Tandy and Zenith sell versions for their hardware.
While generic clones have no trouble running DOS, their owners may not be able to find versions of OS/2 for their computers.
Fortunately, users have been staying away from OS/2 in droves. The new operating system is ridiculously expensive and only marginally compatible with the 20,000 or 30,000 useful DOS programs on the market today.
But Mrozek's point is well-taken. When you buy a computer for your business today, consider the environment in which the machine will operate.
This doesn't mean you have to be a slave to IBM equipment. You just have to be prudent.
If you're in a small business with just a few PCs running as stand-alones or as part of a simple printer and file-sharing network, my original advice may be sound. Any decent compatible will probably do.
But if your business is growing and you see the need for a more sophisticated network down the road, check with the vendor first. Ask if the computer has been tested with various network adapters, or with 3270 emulation boards if you're hooking it to an IBM mainframe or minicomputer.
Likewise, if you think you'll eventually adopt OS/2, make sure your vendor offers a version that will run on your particular piece of hardware.
When you're drawing up specifications for networked PCs, Mrozek adds, try not to mix and match add-on circuit cards from different vendors.
"It doesn't matter what kind of equipment you're using -- all IBM, all Macintosh, all Tandy, whatever," he said. "The fewer the number of vendors you have, the fewer the combinations you have, the better."