The new installation procedure WIMBoot allows you to keep your files in a compressed format and then reserve more space for apps and data.
The minimum requirements for the installation of Windows 8.1 were unchanged compared to the previous version of the operating system. 8.1 With Windows Update, however, was made a change that has a positive effect on space. To allow the use on devices with 16 or 32 GB SSD, especially on tablets, Microsoft introduced a new installation option, called Windows Boot Image (WIMBoot), which allows you to leave more space for applications and data.
The procedure for a typical installation requires that each file is written twice on disk in a compressed format for the restoration and uncompressed. Clearly, this involves a waste of space, especially on cheap devices that integrate an internal memory of small size. On the new devices certified with Windows 8 UEFI, the installation is carried out with WIMBoot. In this case, the files are copied only once, in a compressed format. From the user point of view does not change anything, because they’ll see a C: volume that contains Windows, applications, and data.
The standard layout of the partitions has two system partitions (ESP and MSR), a Windows partition and two recovery partitions. In the new layout, however, there is only one partition for Windows compressed image (install.wim) and for the recovery tool (winre.wim.) In the Windows partition, there are more non-compressed files, but the files pointers, which “point” to the corresponding compressed files in the recovery partition.
The image install.wim takes up about 3 GB, then a 16 GB SSD will be more than 12 GB of available space for apps and user data. If, however, the standard procedure is used, the free space is reduced to 7 GB. Microsoft provides all the documentation to create a WIMBoot from an image with Windows 8.1 Update. The tablet on sale from May will be using the new installation procedure.