Helge Klein from sepago put up a blog entry today discussing the memory overcommit feature of VMware’s flagship ESX product and how it has a very favorable impact in the VDI space since you’re running lots of copies of MS Windows with the same (or similar) applications on them, etc. (this is likely the result of large amounts of transparent page sharing) Helge also mentioned that Microsoft and Citrix both do not have this feature at this time and are downplaying the significance of it. Helge believes it’s this way because Microsoft simply doesn’t have this feature now. While I tend to agree that there probably is some level of wordplay to de-emphasize the competitors product that has a feature that your product doesn’t have, but I also wonder if there isn’t another reason why Microsoft wasn’t so quick to implement this feature. Keep in mind that both Vista and Server 2008 have implementedAddress Space Layout Randomization (or ASLR) as a tactic to reduce the likeihood that OS exploits can compromise a host system. I have not seen anyone comment on whether or not transparent page sharing works with ASLR or not. I would assume that even if it did work, it probably wouldn’t be as effective as it would otherwise normally be. Assuming that’s the case, perhaps Microsoft has pushed off this feature since it’s not something that would greatly benefit Vista/2008. Everyone knows that Microsoft always has higher level of focus on their newer operating systems than they do on the legacy stuff. Perhaps because of this (and my theory on ASLR’s impact to transparent page sharing) they haven’t pushed this higher in their priority list for Hyper-V development. Can anyone out there comment on the effectiveness of transparent page sharing with ASLR? Perhaps since’s MS’s ASLR implementation is rather limited you wouldn’t get quite as penalized as a full blown ASLR implementation. However, without having tested any of this I can only speculate.