ABSTRACT
Mapping Across VMs The question arises: when a new VM is created, just what is copied and what is mapped back to the original? Figure 15.2 clarifies this. You will observe some interesting features of this mapping. For a start, consider the TSR loaded before Windows. Because it is a one and only instance, any data in it is global across all VMs. Think about this — it may be good from the point of sharing data, but there are no safeguards. If one program accesses the TSR and causes its data to be modified, perhaps that will clash with another program's use of the TSR. Commercial TSRs may not be designed with this in mind, so it seems wise to minimize TSR requirements prior to loading Windows.
