Nate Ralph/CNET

Microsoft has laid out the minimum requirements for computers and mobile devices to run Windows 10 -- and has also revealed that pirated copies of Windows will be upgraded too.

Microsoft's operating systems unit Executive Vice-President Terry Myerson took to the stage to talk up the new software at the Windows Hardware Engineering Community (WinHEC) summit in Shenzhen, China. Having already confirmed that current users of Windows 7 and 8 would get a free upgrade to Windows 10, Myerson revealed that the free upgrade will be available to illegal copies of the software too.

The move is an attempt to bring pirate users back into the official Microsoft sphere, and is likely to have the greatest impact in China, where it's reported that the majority of software is not properly licensed. To tackle China, Microsoft has partnered with Chinese companies Tencent and Qihu 360.

Microsoft also revealed that Windows 10 will launch in 190 countries .

Desktop PCs will need to be packing at least 1GB of RAM and 16GB of internal storage to run the 32-bit version of Windows 10. Computers will need to double that up for the 64-bit edition. Screens are required to be bigger than 7 inches for Windows Pro, or bigger than 8 inches for the consumer version.

Mobile devices running the new software will range in screen size from smartphone-sized 3 inches to a tablet-sized 7.99 inches. Resolution will go up to 2,560x2,048 pixels. The lowest resolution screens also require start, back and search buttons.

Various new mobile systems-on-chips will be supported by the new software, including the octa-core Qualcomm Snapdragon 810 and hexa-core Snapdragon 808, and AMD's Carrizo and Carrizo-L. Windows will run on Intel's 14nm Cherry Trail Atom processors, as well as the forthcoming entry-level Atom x3 and the Skylake architecture for desktops.

The minimum amount of RAM required for mobile devices is just 512MB, the same as Windows Phone 8.1. The amount of memory required largely depends on the screen size, with that 512MB powering screens with less than high definition. 1GB of RAM buys you 720p and thereabouts, while 2GB is required for a full HD 1080p screen. Devices displaying 2,560x1,600 pixels and 2,048x1,140 pixels need 3GB or more, while those top-end 2,560x2,048 screens call for at least 4GB.

On the subject of internal storage, Windows Phone devices will contain at least 4GB of space. That has to make room for the firmware itself before you can start saving movies, music and photos, so devices with the bare minimum of 4GB built-in will have an SD card slot to give you extra leg room.