Imagine a completely deconstructed operating system that the user, or service provider, glues together out of just the pieces he needs and pays for it à la carte.

Okay, now imagine Microsoft - which has repeatedly told antitrust authorities the world over for years that it can't possibly pull so much as a hair out of Window for fear it will crash to smithereens around their feet - fielding one.

Well, Microsoft has filed for a US patent on such a beast, leading some folks to speculate that it might be Microsoft's parry to Google's thrust into its platform space. It also might be Microsoft rejigging the whole economics of computers to get a bigger tax.

The patent application - number 20060282899 - was originally filed on June 8, 2005 but didn't get published so other people could read it until December 14, 2006. One of Groklaw's observation posts noticed it and sent it to Groklaw and one of our observation posts saw it there and sent it over to us. Groklaw tries to wring Linux implications out of it but appears to ignore the elephant in the drawing room. Look to your embedded turf, Linux.

The patent application imagines a rudimentary operating system kernel and add-on modules that support hardware, applications, peripherals, networking, tools and stuff like bug fixes, service packs and patches. Digital signatures would certify the use of these add-on modules and digital rights management (DRM) would enforce the terms of the license.

The modules can be time bombed to stop working. Microsoft foresees digital rights indicia covering use to an expiration date or - how's this for striking - the number of times whatever it is is used over a period of time, or the total number of times it's used, or "via metadata processed," whatever that means.

Non-certified applications could theoretically be installed, it says. Additional memory could be provided for. Ditto additional support for concurrent windows and concurrent applications, more processors, advanced sound, game controllers, high-speed disk access, network printing and so on and so on.

So what we've got here is - as the title of the application says - a "System and method of delivery of a modular operating system" - heavy on "method of delivery" - which might as well read method of monetization - and the patent application reads like a business plan - way too humane and intelligible for a patent application.

It acknowledges that the traditional monolithic operating system can "represent a significant portion of the cost of an overall computer system" - and it also acknowledges that the monolithic OS can have way more functionality than the poor wretch using it needs or that it may lack some functions that might be highly desirable.

Then it talks about this small, basic - possibly free - kernel that may do simple operations - figure, it says, basic memory management, system I/O, boot processes and file system support - have fundamental display capabilities and provide basic application support.

Everything else - e-v-e-r-y-t-h-i-n-g e-l-s-e - is customized using the add-on modules that may or may not be free, available for a one-time fee, or part of a monthly subscription.

The fees mentioned in the application are nickel-and-dime microcharges of, say, $2 a month. The user might see a Chinese menu of add-on functions on offer when the system boots - along with payment authorization. He will only pay for what he wants - down to the algorithm - from a pre-paid account, or by online funds transfer or some "other known mechanisms," Microsoft says. No tickee, no shirtee.

The add-on module could be present and just activated, or may have to be downloaded.

Microsoft mentions in passing that this incremental model might ward off malware and reduce the piracy of "full-capacity operating systems." (Yoo-hoo, MIT, do we hear third-world implications here?)

Okay, so now under this prospective new regime you go and buy the flashiest box on the market and get the fattest, fastest pipe for Internet access but you can't use any of the fancy bells and whistles until Microsoft lets you.

Well, that's different. It's always been that whatever you bought from Microsoft would only get better if you threw more hardware at it.

But what OEM in its right mind is going to sell machines that people can't capitalize on? Well, it sounds like computers might get more expensive - or at least less cheap - and that Microsoft will demand a bigger piece of the take.

Now, whether all this is patentable - particularly in the current political climate - or why Microsoft would even bother trying to patent a business model is a headscratcher. Is it a trial balloon? A false trail?

Microsoft claims to have invented "a core function module, a license validation module and a plurality of add-on modules," but surely patent watchers are going to claim prior art. If Microsoft filed a disclosure of prior art with its application, it isn't available outside the patent office.

Meanwhile Microsoft is reportedly testing a pre-paid rental program for Office 2003 in South Africa, Mexico and Romania based on the purchase of cards covering access to the software in three-month increments. If the cards aren't renewed, users can only view documents. Depending on the results Microsoft might go this way with Office 2007 and widen the geography where it's offered.