Abstract: A write-once, read-many optical data storage system which includes an optical disk to which data is written such that a host data system having access to the optical data storage system is enabled to access any one of a predetermined number of logical addresses for storing data at a selected logical address whether or not data had previously been stored at that logical address. The write-once optical disk includes at least one recording surface divided into a plurality of storage segments, including a plurality of sequential data storage segments, each having a host data portion and a logical address portion, and having the physical location of each said data storage segment on said optical disk represented by a physical address different from the physical address of any other data storage segment on said disk, and a plurality of sequential mapping segments, each having a logical address portion.

Abstract: A system for storing and retrieving encoded data on an optical recording medium using pit edge detection is disclosed. The pit extension characteristics of a given medium are determined by first using laser beam test write pulses to form one or more pits on the medium and then detecting the time durational difference between the pulse width of the test write pulses and the duration of the leading edge transitions to trailing edge transitions of the corresponding pits formed on said medium. This difference value may be stored in a certification sector of the medium. Subsequent write pulses are modified in duration in an amount equal to this detected durational difference. For forming a pit that is longer than a predetermined minimum length, the corresponding write pulse is made non-continuous in order to minimize cumulative pit extension.