Abstract: The invented controller is the combination of: an intelligent interface to a SCSI bus, a multi-port buffer memory manager, a formatter, and a local processor port. With the addition of a few components for the device-level interface, the invented controller along with a buffer RAM, a local processor system, and an optional data separator completes a high performance disk, or other mass storage, controller subsystem. The invention is particularly directed to (1) the dual use of a buffer memory as data buffer storage and for storage of instructions to be executed by a SCSI-protocol processor, (2) the architecture of the interface to the SCSI bus, and (3) the instruction set of the SCSI-protocol processor.

Abstract: The invented controller is the combination of: an intelligent interface to a SCSI bus, a multi-part buffer memory manager, a formatter, and a local processor port. With the addition of a few components for the device-level interface, the invented controller along with a buffer RAM, a local processor system, and an optional data separator completes a high performance disk, or other mass storage, controller subsystem. The invention is particularly directed to (1) the dual use of a buffer memory as data buffer storage and for storage of instructions to be executed by a SCSI-protocol processor, (2) the architecture of the interface to the SCSI bus, and (3) the instruction set of the SCSI-protocol processor.

Abstract: A subcode R-W channel data de-interleaving and de-scrambling method and apparatus includes the ability to de-interleave and de-scramble the encoded subchannel data without the necessity of storage elements, by dynamically calculating the final location of each byte of data within a packet as it is read from the CD-Rom. A pack counter monitors the pack number of the current byte of data. An index counter monitors the location of the current data within a pack. A subtractor uses the values from the pack counter and the index counter to obtain an input value, a first portion of which is supplied to a first offset generator. A second portion of the subtractor output is used to select a base address. The first offset generator determines the pack number of the current byte of data after the de-interleave process. A second offset generator receives a value from the index counter and generates a corresponding value.