Microsoft details space-saving WIMBoot for Windows 8.1

April 11, 2014 // 11:01 a.m.

Tags: #microsoft #storage #surface #surface-pro #surface-rt #wimboot #windows #windows-81 #windows-81-update-1

Microsoft has announced a previously hidden feature of the recently-released Windows 8.1 Update 1, which promises to boost available storage on lower-end tablet and hybrid devices: Windows Image Boot (WIMBoot).

Introduced into the Windows platform for the first time with Windows 8.1 Update 1, WIMBoot offers a secondary method of installing Windows on a storage device: instead of the traditional method of extracting the contents of the installation media into directories on the storage drive, WIMBoot sees an image being copied into a dedicated partition with symbolic links being created to offer the illusion that the files are in the expected folders within the main system partition.

The advantage of this method, Microsoft explains, is that the WIMBoot image can remain lightly compressed - not enough to harm overall performance, but enough to mean that the user is given a little more storage space with which to play. 'Let’s assume the WIM file (INSTALL.WIM) is around 3GB and you are using a 16GB SSD,' explains Microsoft's Ben Hunter of the feature. 'In that configuration, you’ll still be left with over 12GB of free disk space (after subtracting out the size of the WIM and a little bit of additional “overhead”). And 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.

'How does that compare to a non-WIMBoot configuration? Well, on that same 16GB system there might be only 7GB free after installing Windows – and then only if you don’t set up a separate recovery image.

Available storage capacity on Microsoft's Windows-based Surface RT and Surface Pro tablets has long been a concern, despite the presence of an SD card slot for expansion. The discovery that the 32GB model of Surface RT offers only 16GB of usable space led to numerous complaints; WIMBoot offers the potential to dramatically reduce the 'wasted' space, while also offering Microsoft and its customers the option to build cheaper 16GB models - something the hefty storage demand of Windows 8 and Windows RT had previously precluded.

Instructions for performing a WIMBoot install yourself are available on the company's Technet knowledgebase.