Monday was the last day on which Windows XP will be sold as a boxed product or licensed to PC manufacturers.
However, 30 June is not the end of the road for the venerable operating system, which was introduced back in 2001. Although Microsoft is keen for users to switch to XP's successor, Windows Vista, that operating system has not been the success that was hoped for by Redmond.
XP will, therefore, continue to be made available in certain circuitous ways. Here is the sequence of events that led to the dilution of Microsoft's XP-killing strategy.
April 2007: The original plan starts to go awry
The original plan was to have the big PC manufacturers stop selling XP-toting machines by January 2008. In early 2007, Vista was already supposed to be the main focus for manufacturers and consumers alike, but the response to the new operating system was somewhat less than enthusiastic.
In April, Dell announced it was to continue offering XP on some of its PCs, in response to thousands of requests from customers. Signs were already appearing that neither manufacturers nor consumers were going to play along with Microsoft's plans.
September 2007: The original plan gets ditched
By September 2007, the message Microsoft was getting from its manufacturer customers was clear: no-one wanted to stop selling XP by January 2008. So, the software giant agreed to extend that deadline to 30 June, 2008. Microsoft also agreed to let manufacturers continue to sell PCs with XP Starter Edition in developing markets until June 2010.
By this point, the manufacturers had also figured out another clever way to extend the life of XP. Because Vista Business and Vista Ultimate come with a licence agreement that includes 'downgrade rights', HP and Dell decided they would continue to sell PCs that came with a Vista licence but had XP pre-installed. Users could then 'upgrade' to Vista if and when they wanted, since they had already paid for it. This trick will work for PCs bought at any time until January 2009.
November 2007: Why don't users want Vista?
Vista's notoriously sluggish performance was supposed to be boosted by its upcoming first service pack, but a new service pack was also due for XP. Testing of the beta versions of both service packs showed that XP SP3 was likely to trounce Vista SP1 in the performance stakes.
At the same time, surveys showed a paltry 13 per cent uptake of Vista in businesses, a year after its launch.
March 2008: A vintage OS for a new breed of laptops
Asus's Linux-toting Eee PC, launched in 2007, was a surprise hit and opened up a whole new market for tiny, cheap, low-powered subnotebooks. Dubbed 'netbooks' by Intel, these devices were set to introduce open-source operating systems to a new generation of users, so Microsoft wanted to make sure Windows would be in there as a rival option.
The problem for Microsoft was that netbooks could in no way handle the resource demands of Vista. The only option, therefore, was to stick XP on them, despite the fact that this would extend XP's life even further. In an attempt to salvage its original plans for killing off XP, Microsoft reportedly set strict limitations on the specifications of any netbooks that could use its operating system.
April 2008: XP fans perceive hints of reprieve
Asked whether Microsoft might consider extending the 30 June deadline for XP sales, Steve Ballmer dropped this hint: "If customer feedback varies, we can always wake up smarter but, right now, we have a plan for end of life for new XP shipments."
Those campaigning for an XP reprieve jumped on Ballmer's words and petitions flew around the internet calling for continued sales of the operating system. These campaigns were to no avail but, around the same time, Lenovo said it was to continue offering an 'XP-recovery disc' with some Vista-bearing PCs all the way through to January 2009.
June 2008: A new breed of desktops also gets XP
Agreeing to allow XP to be sold on netbooks must have been painful enough for Microsoft, but in June it emerged that the company was to allow the same for 'nettops' as well. Nettops are, like netbooks, low-powered and have low specs — the only real difference is that they are desktops rather than laptops &mdash but they are not significantly different from other cheap desktop PCs.
In fact, the only solid criterion set by Microsoft for a nettop that can use XP is that it must be 'ultra-low-cost'.
January 2009: The final execution date?
If all goes according to Microsoft's current plan, XP will finally be killed off in January 2009, although support will continue for some time thereafter. This will give Windows users no choice but to surrender to the charms of Vista. By then, however, Windows 7 will only be a year away.
Why did it have to be this way?
XP is now seven years old. Even with a major security enhancement (XP Service Pack 2), the company benefits from shifting things to the more secure Windows Vista.
It is also critical for Microsoft to build the install base of Vista as quickly as it can. That's because developers won't really start building applications that are Vista-dependent until it occupies a large percentage of machines in active use. Even with 140 million Vista copies sold, there are still extremely few programs that really harness the features of Vista.
After waiting as long as it could, Microsoft has also started talking about what comes after Vista. In an exclusive interview with ZDNet.com.au sister site CNET News.com last month, development head Steven Sinofsky said Windows 7 will use the same drivers as Vista and largely aim to preserve compatibility rather than introduce major changes, as Vista did.
At the "D: All Things Digital" conference, Bill Gates and Steve Ballmer showed off one aspect of Windows 7: its ability to use multitouch input to enable the same kinds of gestures found in Apple's iPhone or Microsoft's Surface computer.
Some argue, though, that it is time to stop slapping new paint on top of Windows, instead rebuilding it from the ground up. Although there is an enormous and unmatched number of programs written for the operating system, preserving all those decades of compatibility is a crutch that has made it harder and harder to innovate, or even update the software.
The New York Times posted an interesting piece on this subject over the weekend. It points to a number of projects inside Microsoft suggesting that it, too, is thinking about other operating-system approaches.
The point raised in the Times piece is an important one. With Linux-based computers starting to make inroads at the low end, and Apple continuing to gain share at the high end, can Microsoft really afford to do business as usual?
Steve Ballmer has vowed that it will never again be five years between Windows releases. It is important to note, though, that even assuming no delays in Windows 7, it will be three years between its release and that of Vista — and that's for a release that doesn't make significant changes under the hood.
It appears that making major changes to Windows has become an increasingly difficult proposition. Perhaps, at some point, Microsoft will have to consider what Apple has done three times with the Macintosh — make major changes under the hood, and use some sort of compatibility layer to maintain its ties to the past.