Abstract: An optical disk drive system with which data may be permanently and correctly stored on removable media. The system includes a drive into which the media, a disk housed in a cartridge, may be removably inserted. The drive interfaces with a host CPU through a storage control unit, which storage control unit may also have other peripheral devices, such as magnetic disk drives, coupled therethrough to the host CPU. A special data format is used for data stored on the disk in order to provide efficient use of and access to the available storage space. The disk is divided into data bands, each data band having a prescribed number of concentric data tracks therein. Each data track is divided into equal length sectors. The data is organized into data blocks, each block being made up of a selected sequence of prescribed data sections. Many of the data sections commence with synchronization bits followed by the data to be stored. The data of each data section is adapted to fit within each data sector on the disk.

Abstract: An optical system for writing and reading data from a rotating optical storage disk, comprising a first, second and third coherent light source, providing coarse seek, reading, and writing functions, the three writing sources sharing a plurality of optical elements in common, all cooperating to provide for the coarse seek, fine seek, focus and tracking functions of the device. The read and the write optical beams are optically coupled together to ensure proper spacing of a newly written track with regard to the previously written track.

Abstract: A system for aligning data with corresponding sector marks in an optical disk storage system. In an optical disk storage system, data is written into a number of concentric bands, each of which contains a servo track and a number of data tracks. Each band is divided circumferentially into a series of sectors which are defined by marks in the servo track. The beginning of a sector is detected by identifying one of the marks in the servo track, and the beginning of a data record must coincide with the beginning of a sector. Recorded during the manufacture of the storage disk of the present invention, are pairs of special tracks wherein the first sector mark on a track is identified by an index mark, and the adjacent data track has a beginning of data mark recorded at a fixed location relative to the index mark. The disk read/write head is moved over one of these pairs and the difference in time between the occurrence of the index and occurrence of the beginning of data mark is measured.

Abstract: A self contained, replaceable diode laser module for providing a fully collimated, de-astigmatized, and circular cross-sectioned beam. In the preferred embodiment a first compound spherical lens partially collimates the beam. An in-line combined cross-section modifier system then de-astigmatizes and modifies the cross-section of the beam. The beam modifier system is comprised of first and second triangular prisms oriented at non-normal angles to the path of the beam. This allows both the cross-section and the astigmatism of the beam to be corrected. A planar mirror between the first and second prisms directs the beam from the first prism to the second prism, so that the beam can exit the second prism co-axial with the incident beam path. The beam then enters the second collimating subsystem.

Abstract: Apparatus and methods are disclosed for writing data on a track in an optical disk data storage device wherein the track is divided into two parts and binary one bits are written into one part of the data track while binary zero bits are written into the second part of the data track. Detection of data written in this manner is performed using two read coherent radiation beams each positioned over one of the parts of the data track. A binary one is detected if the signal from the beam over the first part of the data track is greater than the signal from the beam over the second part of the data track, and a binary zero is indicated if the signal from the beam over the second part of the data track is greater than the signal of the beam over the first part of the data track. In order to detect the data from the two read beams, they must be aligned accurately over the two halves of the data track. To aid this alignment, a third larger beam is used to measure the total energy from the data track.