System for stop buffering when a count of stored data blocks from a dvd matches an associated data block number of a requested data block set

Abstract

A method and apparatus for transferring optical data from a DVD in response to a request from a host. When a data request is issued, a portion of the request containing the target ID for the target data block is used by a comparator circuit to locate the target data block. Another portion of the request containing the number of data blocks requested is used by a monitoring circuit to monitor data block transfer from a DVD to a data buffer once the target data block is located. The monitoring circuit stops data transfer when all of the requested data blocks have been transferred. Each data block is transferred into a data buffer containing areas separated by pointers. In a scratch area of the data buffer, the data block is error corrected, error checked and descrambled. After error checking and descrambling, the data portions of the data block are transferred to a data area in the data buffer, the auxiliary portions of the data block are transferred to an auxiliary area in the data buffer and the status of the error checking is latched into registers. Before any data is transferred from the data buffer to the host through an interface, the data status in the registers is checked. If no error is found in the data, then the corresponding data portions of the data block is transferred to the host.