The sad news that Osborne Computer Corp. had gone into bankruptcy was only a few hours old when my friend the computer buff went online with an urgent message to the whole network: "Buy Osborne."

It wasn't investment advice; poor Adam Osborne collapsed so fast he never managed to go through with the public stock offering he'd been planning. The computer buff's buy order concerned not stock, but computers. The message was that now is a great time to buy an Osborne Computer.

Why should you plunk down good money for an electronic orphan? The buff has a theory, which goes like this:

The Osborne bankruptcy had a lot to do with the personal computer market, with IBM, and with some bad decisions and bad luck at Osborne. But it had almost nothing to do with the Osborne I, which was always a terrific machine bundled with terrific software at a pretty good price. If you buy an Osborne now, you'll get the same terrific machine and software at a fantastically good price.

The Osborne I, with its bundle of CP/M and four top-of-the-line applications programs, came out at $1,795--and sold like crazy. By this summer the price had fallen to $1,395. Today, though, an after-the-fall Osborne can be had for $900 or so, and I would not be surprised if somebody chopped off another $150 or so in the next few weeks. At these prices, you're getting an excellent deal just on the software--with a fine portable computer essentially thrown in for free.

And anybody who thinks Osborne will be the only failure in the personal computer business has just not been paying attention. There are about 150 makes of personal/home computers today. In five years, after the long-dreaded "shakeout" is all shaken out, there will be, oh, 20 or so.

To me, this look into the future is almost irrelevant for my decision on a computer today. If I find a machine I like now with the software I need now at a price that's right, I'll buy it. Once the warranty runs out (this is normally 90 days), I don't need the manufacturer anyway.

But if you're worried that supplies of parts and peripherals and software will dry up (a legitimate concern)--then you'd better stick to the biggies: IBM, Digital, Hewlett-Packard, Radio Shack, Apple. A lot of smaller computer makers are going to go belly up.

Further, the idea of buying an Osborne today represents the extreme application of the fundamental rule of the personal computer market: if you wait a while, the price will come down.

This rule has held true for every personal computer, including the IBM, and it probably will hold true down the line for another year or more. Apple's Lisa seemed to be the hottest thing going when the first models hit the market this spring at $9,995. Five months later, the price is $8,200; it almost has to drop some more. If Lisa isn't immune, nobody is.

If you like the idea of buying at the bottom--if you don't want to see your $10,000 computer drop 20 percent of its retail value overnight--it is fairly safe to predict that the Osborne I today is as good a bargain as there will ever be.

Like most bargains, the post-bankruptcy Osborne has its flaws. The computer had some problems even before its manufacturer folded: the screen--five inches!--is too small and the word-processing programming, WordStar, is too complicated (you want to hit four keys for one simple command?). The first problem can be solved, though, with a $125 investment in a 12-inch monitor and a cable. The second problem hasn't seemed to bother hundreds of thousands of WordStar users, so perhaps it won't trouble you, either.

How about service? With no company behind the machine, will a broken Osborne ever get fixed? The outlook here is pretty good. For one thing, a lot of stores already service the Osborne, and the local outlets say they'll continue to do so. For another, Adam Osborne built his brainchild out of fairly standard parts; just about any computer shop can repair a Siemens disk drive or replace a TI logic chip.

How about new peripherals and new software? These concerns should be less acute with the Osborne than they might be with some other extinct machines. There are, after all, some 125,000 Osbornes in use today, and that is a pretty solid market for a software seller to shoot at. Moreover, there is a strong network of Osborne Users' Groups around the country (three in the D.C. area alone), and they maintain a continually growing library of public domain (i.e., free) software.

The computer buff's advice is good advice for you only if you're looking for a good deal on a business computer that fits today's status quo. If that's what you need, you could do a good deal worse than the computer industry's first real orphan, the Osborne I.