Patent ID: 6038636
Filing Date: 2000-03-14
Classification: G06F

Abstract:
A system for reclaiming memory filled by invalid data on a flash memory device, the system comprising:a flash memory device divided into a plurality of individually erasable memory portions;a designated memory area;a memory reclamation mechanism configured to copy all valid data from one of the memory portions of the flash memory to the designated memory area, erase the memory portion that was copied, write the valid data from the designated memory area contiguously to the next available free space on the flash memory device, and to repeat the copying, erasing, and writing for each of the plurality of memory portions on the flash memory device in a consecutive order, such that the flash memory device contains no invalid data and contains a plurality of contiguous memory portions which are free;a pointer configured for keeping track of the address of the next available free space on the flash device, wherein the reclamation mechanism updates the pointer after writing the valid data to the next available free space;wherein the designated memory area has area a memory capacity at least as large as one of the memory portions, wherein the plurality or memory portions have successive addresses from a first portion to a last portion, wherein the reclamation mechanism is configured to start the copying, erasing, and writing at the first portion and continue without interruption from portion to portion consecutively through the last portion;wherein the next available free space comprises the next erased location on the flash memory device beginning from the first portion on the device, and wherein the reclamation mechanism contiguously writes the valid from the designated memory area to the next available free space such that all valid data on the flash memory device becomes contiguous on a first contiguous segment of the flash memory device and all free memory on the flash memory device becomes contiguous on a second contiguous segment of the device after reclamation mechanism has repeated the copying, erasing, and writing for each of the portion on the device.