Patent ID: 6101576
Filing Date: 2000-08-08
Classification: G06F,Y10S

Abstract:
A cache memory control method in a character-image data generating system having a first cache memory from which stored character-image data vanishes owing to cut-off of a power supply, and a second cache memory in which stored character-image data is held even if the power supply is cut off, said method comprising the steps of:saving newly generated character-image data that has been used in the first cache memory if said first cache memory is not full;saving said newly generated character-image data in said first cache memory, after some of the character-image data that has been saved in said first cache memory is transferred to said second cache memory, if said first cache memory is full;searching said first cache memory when prescribed character-image data is necessary, searching said second cache memory if the prescribed character-image data is not found in said first cache memory, and outputting character-image data retrieved by the search;generating the prescribed character-image data if the data cannot be retrieved from either of the cache memories, outputting the generated character-image data and saving said generated character-image data in said first cache memory;transferring character-image data, which has been saved in said first cache memory but not in said second cache memory, from said first cache memory to said second cache memory to save the character-image data in said second cache memory; andtransferring some of the character-image data that has been saved in said second cache memory to said first cache memory when power is introduced, wherein transfer of character-image data from said first cache memory to said second cache memory is carried out after the system having said first cache memory has stopped outputting character-image data.