Microsoft shrinks Windows down to size for tablets

Microsoft has cut down the amount of space Windows takes up on tablets in a bid to boost the ailing tablet OS.

Windows Image Boot (WIMBoot) has been unveiled by Michael Niehaus, senior product marketing manager for Microsoft's Windows Commercial division.

In a blog post, Niehaus said that instead of extracting all the individual Windows files from an image (WIM) file, they remain compressed in the WIM.

"From the user's perspective, nothing looks any different: You still see a C: volume containing Windows, your apps, and all of your data,|" said Niehaus.

The new option is geared towards tablets with "smaller disks, e.g. devices with 16GB or 32GB SSDs or eMMC storage, while still ensuring that there is plenty of storage left for apps and data."

Niehaus said the option is supported with all SKUs of Windows 8.1, with the Windows 8.1 Update. "We're not talking about a different version of Windows, just a different way of installing it," he said.

Space is saved on tablets by copying the WIM file into a separate "images" partition, then using DISM to create pointer files from the standard C: operating system volume into the WIM file.

Niehaus said that assuming a WIM file is 3GB in size on a 16GB SSD, with a little overhead, users would still have 12GB of free disk space. A non-WIMBoot configuration might only leave 7GB of free space in comparison, said Niehaus.

"The same WIM file (which is read-only, never being changed in this process) can also be used as a recovery image, in case you want to reset the computer back to its original state," he said.

However, to increase storage space, users should expect a performance trade-off. "There is some performance impact, which is why this only targets new computers with small SSD or eMMC-based hard drives."

Niehaus also said that the option will not stop Windows from increasing in space as new options and features are added to the OS.

He also admitted that at the present time, the WIMBoot option was "more of a manual process" as tools such as Windows Deployment Services (WDS), Microsoft Deployment Toolkit (MDT) and Configuration Manager do not support it natively.