Microsoft is to make Windows 8.1 available on devices with as little as 16GB of storage. It’ll do so using a compression technique first developed during the making of Vista.

The move will allow Windows to be available for even small-capacity devices such as tablets that use a solid state drive.

The technique is called Windows Image Boot (WIMBoot). Put simply, it means not using the traditional installation of taking a compressed installation file, unpacking it and installing the Windows system files individually onto a hard drive.

Instead the compressed file is dumped straight on the disk as a read-only file in a separate partition (shown above as “Images”.) The device is then set up so that it effectively decompresses, reads and uses the individual system files as and when it needs to. That can mean the whole of Windows only needs to use up a little over 3GB of storage space.

Device makers and users will need to allow for some extra space as any changes or updates must be stored on the main partition of the hard drive. The Windows installation remains read-only, so any changes have to work a little like adding an appendix to a book rather than editing the original text.

Microsoft notes an added benefit of the set-up: because the original Windows installation is never changed, it can act as a recovery image. Not needing a separate recovery image frees up more space.

If the system works well, it will remove a significant limitation to the idea of making Windows 8 tablets. As ComputerWorld notes, Microsoft was forced to use a minimum of 64GB storage on Surface Pro tablets, pushing up prices, but even that didn’t leave enough free space for many users.

How much WIMBoot affects performance, if at all, remains to be seen. The setup uses pointer files on the main hard drive that mean the device doesn’t need to decompress the entire installation file every time it needs to access Windows, but rather can go straight to the relevant data. There’s still going to be an element of decompression though, which could cause a tiny delay.

If you’re feeling particularly ambitious, Microsoft has released some tools so that you can try out the WIMBoot technique, but you’re on your own and there are no promises of success or reliability.