Some memory areas may be shared among processes, e.g. kernel areas and shared libraries.
Most operating systems assume at least one local and one global space.
To promote sharing of data between processes, MAS operating systems aggressively use virtual aliases to map physical memory locations into the address spaces of multiple processes. Virtual aliases create multiple TLB entries for the same physical data leading to reduced TLB efficiency. The MAS model is supported by dividing the virtual address space into several regions. Region identifiers associated with each region are used to tag translations to a given address space. On a process switch, region identifiers uniquely identify the set of translations belonging to a process, thereby avoiding TLB flushes.