Patent ID: 8112558

Claim:
A non-transitory computer-readable portable storage medium used by a computer managing a plurality of frame buffers and storing a program enabling the computer to execute a process, the process comprising: preparing an area in which data of a valid chain indicating a connection among frame buffers storing valid image data of the plurality of frame buffers and data of a vacant chain indicating a connection among frame buffers storing no valid image data, is stored, on memory; and generating/updating data of the valid chain and the vacant chain when valid image data is stored in one of the plurality of frame buffers and storing it in the memory, wherein the area in the memory, which stores the data of the valid chain and the data of the vacant chain comprises: a chain leading block number storage area for storing a first number indicating top of the valid chain and a second number indicating top of the vacant chain, of a block among blocks corresponding to the plurality of frame buffers one to one; and a block individual data storage area for storing data indicating whether valid data is stored in a frame buffer corresponding to each of the blocks and numbers of blocks connected before and after the block on the valid chain or the vacant chain, a last block number of the valid chain as a number of a block connected before the top block of the valid chain, and a last block number of the vacant chain as a number of a block connected before the top block of the vacant chain.