1. A computer with an expanded addressing capability comprising: processor means having an address bus with a plurality of address lines for generating and supplying addresses through said address bus; a plurality of addressable banks which are divided into a plurality of distinct address ranges, one of said address ranges including a plurality of read-only memory banks, each of which bank being implemented in the form of at least one monolithic integrated circuit having first and second bias supply terminals, said first bias supply terminal being designed to be connected to a reference potential and said second bias supply terminal being designed to be connected to a biasing potential, said plurality of addressable banks comprising a first plurality of read-only memory banks within one of said address ranges for storing respective programs to control respective items of peripheral equipment operatively associated with said computer, a second plurality of read-only memory banks within a second of said address ranges for storing respective programs and/or data for respective applications which can be performed by said computer, and a plurality of read-and-write memory banks within another of said address ranges for storing variable information for use by said computer, said second of said address ranges, in addition to a plurality of read-only memory banks, also having an addressable hardware bank comprising at least one item of peripheral equipment which is controlled by one of said read-only memory banks of said one of address ranges; and banks preselection means for preselecting any bank of any address range such that if any address is supplied on said address bus of said processor means, it will be effective only at the preselected bank and all other non-preselected banks will be inactive and not addressed by said processor means, said bank preselection means being arranged to cause said second bias supply terminal to be connected to said biasing potential when said bank is selected and to be connected to said reference when said bank is not selected.