Patent ID: 6389509
Filing Date: 2002-05-14
Classification: G06F

Abstract:
A memory cache device for a compact disc-read only memory (CD-ROM) device for use with a host computer, the cache device comprising:a CD-ROM device for reading a compact disc, the device having an onboard random access memory (RAM) cache; a hard disk dedicated solely for storing data copied from a compact disc in the CD-ROM device; means for initially filling a clone area of the hard disk with data from the compact disc using a sequential striped fill process for copying a plurality of blocks of data, wherein a first block of data of a sequence of data blocks from the compact disc is accessed and copied onto the hard disk, then a second block of data in the sequence of data blocks is not copied to the hard disk, then a third block of data in the sequence of data blocks is copied from the compact disc to the hard disk, the fill process continuing until the entire capacity of the hard disk devoted to cloning the compact disc is full, while leaving sufficient area for storage of blocks not initially copied during the fill process; means for initially filling a cache area of the hard disk with data from the compact disc using the sequential striped fill process for copying a plurality of blocks of data from the compact disc to the hard disk, the fill process continuing until the entire capacity of the hard disk devoted to the cache area is full, while leaving sufficient area for storage of blocks not initially copied during the fill process; means for receiving read requests from the host computer and fulfilling the requests, the receiving means comprising a pipelined read process, wherein data that is stored on the hard disk and comprises a portion of the read request is accessed from the hard disk and transmitted to the host computer, and data that comprises a portion of the read request and is stored on the compact disc, is simultaneously being accessed while the hard disk is transmitting the data thereon to the computer, the CD-ROM device accessing the data on the compact disc and storing the data in the onboard RAM cache thereof, such that the data from the compact disc is transmitted to the computer upon completion of the transmission of data from the hard disk to the computer, the pipelined process being repeated until all requested blocks of data have been retrieved and transmitted to the computer; and means for filling in blocks of data in the clone area and the cache area of the hard disk not copied from the compact disc during the sequential striped fill process, the fill means filling in not copied blocks of data during interludes between read requests from the computer.