Abstract: The present invention relates to methods and apparatus for dynamically varying a linear velocity of an optical drive during a write operation to an optical disc to reduce the likelihood of a buffer under-run event. By reducing a linear velocity and writing speed while the optical drive writes on the disc, an embodiment of the invention preserves the buffer and reduces a minimum data transfer rate required to sustain writing to the disc for a sustained period of time. The basic components of one embodiment of a CD-RW drive (100) in which the present invention may be implemented include a controller (110), a microcontroller (112), a nonvolatile memory (114), which stores firmware (116) executed by the microcontroller (112), a buffer (118), a spindle motor (120) and an optical pick-up (122).

Abstract: An optical disk device has a motor that rotates an optical disk, motor control means for making constant a rotational speed of the motor, and write control means for changing a write frequency of information written to the optical disk such that writing of the information onto the optical disk is made at a substantially constant recording density, irrespective of a track on which the information is recorded.

Abstract: A memory device provided on a one-chip microcomputer includes a high-speed ROM and a low-speed ROM which are arranged in the same address space and thus can be addressed by the same address pointer, wherein information requiring a high-speed operation and/or having a high access frequency is stored in the high-speed ROM and information requiring no high-speed operation and/or low access frequency is stored in the low-speed ROM. Another memory includes a pair of first and second memories, wherein the first memory includes an extended instruction for accessing the second memory, which thus serves as a virtual memory. The second memory is accessed only when reference is made to an address of an operand of an instruction which immediately follows the extended instruction.