A computer memory device having stored thereon a computer program for allowing an information processing apparatus to execute a process of recording data on a multilayer optical disk, the program comprising the steps of:
- (a) encoding data to be written;
- (b) modulating the encoded data to generate a plurality of modulated data blocks corresponding to different recording formats;
- (c) sequentially writing the modulated data blocks in the different recording formats to different layers of the optical disk;
- and
- (d) controlling the writing of the modulated data blocks in the different recording formats so that writing processing per unit of modulated data is completed within processing time per unit of data encoded in the step (a).