The title says "120 megs of RAM", but I wonder if that's at all comparable to a real machine with 120 MB. I imagine that the "120 MB" VM is running on a beefy

The title says "120 megs of RAM", but I wonder if that's at all comparable to a real machine with 120 MB. I imagine that the "120 MB" VM is running on a beefy host with tens (or hundreds) of gigabytes of RAM shared between the guest VMs and also used for disk cache. It seems likely that accessing a guest's virtual disk would actually hit the host's disk cache a lot of the time (especially when that guest has been busy recently); that would improve the speed of disk access for that VM enough that it could make up for the lack of memory for disk cache within the guest. This is purely speculation, but I would be interested to see if there is any actual research to back it up. I suppose if the guest in this instance is not swapping very often, then this is fairly irrelevant, but the article didn't mention anything about swap.