Oh yes, and buys Autonomy, a fast-growing specialist in enterprise knowledge management.

Here’s the news from HP’s announcement:

As part of the transformation, HP announced that its board of directors has authorized the exploration of strategic alternatives for the company’s Personal Systems Group. HP will consider a broad range of options that may include, among others, a full or partial separation of PSG from HP through a spin-off or other transaction. (See accompanying press release.)

HP will discontinue operations for webOS devices, specifically the TouchPad and webOS phones. The devices have not met internal milestones and financial targets. HP will continue to explore options to optimize the value of webOS software going forward.

In addition, HP announced the terms of a recommended transaction for all of the outstanding shares of Autonomy Corporation plc for £25.50 ($42.11) per share in cash.

A few quick comments. First, the failure of webOS does not surprise me. There is not much wrong with webOS as such; in pure technical terms it deserves better. Its focus on adapting web technologies for local mobile applications is far-sighted; it is a more interesting operating system than Android and in some ways it is surprising that it went to HP and not to Google, which is a web technology specialist.

The problem is that HP, despite its size, is not big enough to make a success of webOS on its own. This was my comment from just over a year ago:

Mobile platforms stand (or fall) on several pillars: hardware, software, mobile operator partners, and apps. Apple is powering ahead with all of these. Google Android is as well, and has become the obvious choice for vendors (other than HP) who want to ride the wave of a successful platform. Windows Phone 7 faces obvious challenges, but at least in theory Microsoft can make it work though integration with Windows and by offering developers a familiar set of tools, as I’ve noted here.

It is obvious that not all these platforms can succeed. If we accept that Apple and Android will occupy the top two rungs of the ladder when it comes to attracting app developers, that means HP webOS cannot do better than third; and I’d speculate that it will be some way lower down than that.

Frankly, if HP did not want to do Android, it should have stuck with Microsoft. But this is where the webOS news ties in with the announcement about he Personal Systems Group. HP fell out with Microsoft last year, as I noted in my 2010 retrospective. I said the two companies should make up; but it looks as if HP is more inclined to give up on PCs and pursue other lines that have better margins – like enterprise software.

I am puzzled though by the PSG announcement. It is always curious when a company announces that it might or might not do something, and the fact that HP says it is considering a spin-off of its PC division will be enough to makes its customers uncertain about the long-term future of HP PCs and some of them will buy elsewhere as a result. It would have paid HP either to say nothing, or to be more definite and aim for a speedy transition.

All this, on the eve of Microsoft’s detailed unveiling of Windows 8. What are the implications? More than I can put into a single post; but like Gartner’s reports of dramatically declining PC sales in Western Europe presented earlier this week, this is a sign of structural change in the industry.

Microsoft will be glad of one thing: it no longer has this major partner promoting a rival mobile and tablet operating system. Note that HP still is a major partner: even if it sells the Personal Systems Group, its server and services business will still be deeply entwined with Windows.