Microsoft is mandating the use of the UEFI (Unified Extensible Firmware Interface) secure boot-loading capability with Windows 8 in such a way that "the end user is no longer in control of their PC," charged Red Hat developer Matthew Garrett in a blog entry posted Friday.

Microsoft has claimed that this charge is based on a misunderstanding of the company's intentions. "At the end of the day, the customer is in control of their PC," said Microsoft program manager Tony Mangefeste in another blog posting from Microsoft.

The controversy took root on Tuesday, when Garrett that Microsoft-certified computers running Windows 8 may not be able to be loaded with copies of other OSes, such as Linux. Users could not install Linux as a second OS, or replace Windows with a copy of Linux, Garrett argued.

Windows 8 will require its host computer to use the UEFI, the low-level interface between the computer firmware and the OS. Marketed as a replacement to BIOS, UEFI provides a secure boot protocol, which requires the OS to furnish a digital key in order to be loaded by the machine. UEFI then can block the operations of any programs or drivers unless they have been signed by this key, a move that should prevent malware from infecting machines by changing the boot-loading process.

With Windows 8, Microsoft will require hardware manufacturers (those wishing to display the Windows logo on their units) to ship their machines with secure boot enabled. Each machine would then require a digital key from Microsoft, the hardware manufacturer or, if it uses another OS, a secure key for that OS.