Copies of Microsoft's former flagship operating system will be placed on XO laptops as part of a limited field trial. As a result, for the first time in a long while, it finds itself in the role of PC hardware tester.

Microsoft says it's testing Windows XP one more time, for deployment in a new environment: the OLPC system for emerging markets.

Yesterday, the company said the goal of its trials is to ensure a "high-quality Windows experience" on OLPC's devices. If it goes well, as early as the second half of next year XP could be available for the device.

If governments are interesting in possibly putting Windows on its laptops, Microsoft recommended that they keep in touch with the company. However, those buying the PCs at retail in the US and Canada have been left out in the cold: the company will not make it available here.

Even with the tests, XP on XO is not a sure thing according to Microsoft engineers. One wrote in a blog post that the decision would not be made until after the field tests. Essentially, the future of Microsoft on the OLPC rests in the hands of those who provide feedback.

A Microsoft announcement stated that the company was attempting to back away from statements made by OLPC chair Nicholas Negroponte, which said XP was a go on its devices. But apparently it's not: One of the main problems is actually getting the operating system as well as Microsoft Office on the device: it only has 1 GB of memory, Microsoft claims it needs at least 2 GB to make it work.

The announcement also poses another interesting conundrum: another extension of the lifecycle for XP. Perhaps due primarily to its larger size, Vista appears to be unable to be ported to the OLPC form factor, which uses flash drives.

The Redmond company plans to publish design guidelines for XP on flash-based devices, which essentially means the company will still develop for the operating system it once said it was transitioning away from.