Computer system with a paged non-volatile memory

• Main Authors: CHRISTESON; ORVILLE H, GABE; DOUGLAS L, MURPHY; SEAN T, EWERTZ; JAMES H
• Format: Patent
• Language: English
• Published: 06.12.1994
• Edition: 5
• Subjects: CALCULATING; COMPUTING; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; PHYSICS

A computer system wherein a paging technique is used to expand the usable non-volatile memory capacity beyond a fixed address space limitation. The computer system of the preferred embodiment includes a flash memory component for storing non-volatile code and data including a system BIOS in the upper 128K of memory. The useful BIOS memory space is effectively increased while maintaining the address boundary of the upper 128K region. The address space of the non-volatile memory device is logically separated into distinct pages of memory (Pages 1-4). Page 1, Page 3 and Page 4 may be individually swapped into the address space originally occupied by Page 1 (the swappable page area). In the preferred embodiment, Page 2 is held static and thus is not used as a swap area. Each of the swappable pages contain processing logic called swapping logic used during the swapping or paging operation. The swapping logic operates in conjunction with paging hardware to effect the swapping of pages into the swappable page area. The high order processor address lines are input by a page decoder. The page decoder is used to modify the address actually presented to the non-volatile memory device. A page register is used by the processor to select a page in non-volatile memory. In an alternative embodiment, several different forms of configuration or identification information may be stored in a page of non-volatile memory.