Apparatus and method for reproducing information data from optical cards

An apparatus for reproducing data from an optical data recording medium, the apparatus comprising:

• memory means for storing data read from the optical data recording medium together with an address of the read data;
• first determining means for determining whether data at a target address which is to be reproduced is stored in said memory means;
• first reading means for, when said first determining means determines that the data is stored in said memory means, reading data from said memory means;
• and
• second reading means for, when said first determining means determines that the data is not stored in said memory means, accessing the target address of the optical data recording medium to read data, wherein said second reading means comprises:
• a buffer memory for storing data read from a given recording address;
• second determining means for determining whether an access address currently being accessed is the target address;
• means for, when said second determining means determines that the access address is the target address, outputting a content of said buffer memory;
• and
• means for, when said second determining means determines that the access address is not the target address, writing the content of said buffer memory in said memory means.

An apparatus for reproducing data from an optical data recording medium having a large number of parallel linear recording tracks, each of said tracks having a data recording area and two address recording areas for recording an address thereof at two ends of the data recording area, the apparatus comprising:

• first reading means for continuously accessing one of said two address recording areas and said data recording area;
• first determining means for determining whether an address can be identified from data read from said one of said two address recording areas;
• second determining means for, when said first determining means can identify the address, determining whether the identified address is a target address which is to be reproduced;
• a buffer memory for storing data read from said data recording area;
• means for, when said second determining means determines that the identified address is the target address, outputting a content of said buffer memory;
• second reading means for, when said first determining means cannot identify the address or said second determining means determines that the identified address is not the target address, accessing the other of said two address recording areas after said first reading means performs an access operation;
• third determining means for determining whether or not an address can be identified from data read from said other of said two address recording areas;
• fourth determining means for, when said third determining means can identify the address, determining whether the identified address is the target address;
• means for, when said fourth determining means determines that the identified address is the target address, outputting a content of said buffer memory;
• and
• means for, when said third determining means cannot identify the address or said fourth determining means determines that the identified address is not the target address, clearing the content of said buffer memory.

An apparatus for reproducing data from an optical data recording medium having a large number of parallel linear recording tracks, each of said tracks having a data recording area and two address recording areas for recording an address thereof at two ends of the data recording area, the apparatus comprising:

• first reading means for continuously accessing one of said two address recording areas and said data recording area of a plurality of tracks;
• first determining means for determining whether addresses can be identified from data read from said one of said two address recording areas;
• second determining means for, when said first determining means can identify the addresses, determining whether the identified addresses include a target address which is to be reproduced;
• a buffer memory for storing data read from said data recording area;
• means for, when said second determining means determines that the identified addresses includes the target address, outputting data of the target address from said buffer memory;
• second reading means for, when said first determining means cannot identify the addresses or said second determining means determines that the identified addresses do not include the target address, accessing the other of said two address recording areas of each of said plurality of tracks after said first reading means performs an access operation;
• third determining means for determining whether addresses can be identified from data read from said other of said two address recording areas;
• fourth determining means for, when said third determining means can identify the addresses, determining whether the identified addresses include the target address;
• means for, when said fourth determining means determines that the identified addresses include the target address, outputting data of the target address from said buffer memory;
• and
• means for, when said third determining means cannot identify the addresses or said fourth determining means determines that the identified addresses do not include the target address, clearing a content of said buffer memory.