"...Drexler Technology today announced that its systems architecture invention for optical disk recording systems has been patented in Japan and is now being made available for exclusive licensing, with sublicensing rights, for DVD and CD-R optical disk recording. The term of Japanese Patent No. 3005645 is until February 23, 2010.

The patent is entitled, "Method of Reading and Writing Files on Nonerasable Storage Media," and describes a method of achieving "apparent erasability". This enables features such as "packet writing" of small files, "drive-letter access", the ability to drag-and-drop files, and the capability to randomly erase separate files encoded on nonerasable or rewriteable DVD and CD-R optical disks used in laser recording/retrieval systems.

Drexler Technology's systems architecture invention applies to the recording and retrieval of laser written data on optical memory disks automatically controlled by "computer operating system" commands. The patent is applicable to laser recordable DVD or CD-R disks. The systems architecture invention makes nonerasable and rewriteable optical disks appear to be erasable.

Utilizing the invention, nonerasable and rewriteable optical disk drive systems act as if they are instantly erasable like magnetic hard drives. This enables PC system features such as "drive-letter access", "packet writing" of small files without wasted overhead, and the ability to drag-and-drop files and to randomly erase separate files..." NULL