Microsoft is launching a program to promote the use of its Windows OS in ultra low-cost PCs, one effect of which will be to limit the hardware capabilities of this type of device, IDG News Service has learned.

Microsoft plans to offer PC makers steep discounts on Windows XP Home Edition to encourage them to use that OS instead of Linux on ultra low-cost PCs (ULPCs). To be eligible, however, the PC vendors that make ULPCs must limit screen sizes to 10.2 inches and hard drives to 80G bytes, and they cannot offer touch-screen PCs.

The program is outlined in confidential documents that Microsoft sent to PC makers last month, and which were obtained by IDG News Service. The goal apparently is to limit the hardware capabilities of ULPCs so that they don't eat into the market for mainstream PCs running Windows Vista, something both Microsoft and the PC vendors would want to avoid.