US Patent 4779191: Method and apparatus for expanding the address…

An address space, referred to herein as Moby space, may be defined having an address range greatly exceeding the direct addressing range of a particular computer, whereby each address in Moby space may be unique. Ranges of Moby space are swapped into and out of local memory space of the computer in question by processes referred to as reconciliation and dereconciliation. These processes are accomplished by maintaining in the computer, data structures which associate, typically on a per page or per section (multiple page) basis, each local page or section with its current Moby page or section. In addition to this address association and conversion, information being swapped must be scanned to separate the pointers from data and to appropriately convert pointers, but not data, as required during the swap. Achievement of aspects of the reconciliation and dereconciliation in separate hardware, particularly the maintenance of a running count of pointers to each page or section in local memory to identify which pages or sections may safely be swapped out, relieves the main processor of much of the overhead associated with these processes.