We’ve already told you that Microsoft was yet to upgrade its Surface storage FAQ, so information on the available space on the upcoming Pro tablet remains pretty vague.

The company, however, told us in a statement that the 128 GB version of the Surface with Windows 8 Pro offers users 83 GB of available space, which means that the operating system and the pre-installed software eat up approximately 45 GB.

While that’s clearly a lot of space, Microsoft also reminded us that the Surface Pro comes not only with an USB 3.0 port to connect external storage devices, but also with SkyDrive support for an extra 7GB of free space.

If the figures sent to us by Microsoft are the same on the 64 GB version, this means that the entry-level Surface Pro comes with only 19 GB of available storage. That doesn’t sound good.