Disc having a data read-only area and a data recording arm and a recording reproducing system therefor

A system for information recording/reproducing on an optical disc having a plurality of tracks divided into a plurality of sectors, wherein said optical disc includes:

• a light sensitive recording material formed on all tracks and each sector has a sector identifier portion in which address information is recorded and a data field portion for recording/reproducing data, said tracks including first tracks defining a data read-only area in which area has been recorded in a form of concave and convex pits in data field portions, and second tracks defining a data recording/reproducing area in which data can be recorded, a data field identifier flag recorded in the sector to discriminate between first tracks of said data read-only area and second tracks of said data recording/reproducing area, and at least one dummy sector provided at beginning portions of said data read-only area and/or said data recording area with the data field portion of said dummy sector being recorded with no data;
• said system including:
• detection means for detecting said data field identification flag of a sector,
• reproduction condition control means for switching signal-reading conditions between said data read-only area and said data recording/reproducing area in response to said area discriminating means, and
• data reproduction compensation means, for undetected address information of the target sector, for causing the data reading of said reproducing means to read data from the data field portion of said target sector after a time delay corresponding to one sector after detecting the address information of the sector identifier portion of a sector just preceding to said target sector, and therefore setting data reproducing conditions to cause said reading by referring to the data field identification flag of said preceding sector.

A system for information recording/reproducing on an optical disc having a plurality of tracks divided into a plurality of sectors, wherein said optical disc includes a light sensitive recording material formed on all tracks and each sector has a sector identifier portion in which address information is recorded and a data field portion for recording/reproducing data, said tracks including first tracks defining a data read-only area in which area has been recorded in a form of concave and convex pits in data field portions, and second tracks defining a data recording/reproducing area in which data can be recorded, and includes guard areas each having a width corresponding to a plurality of tracks and to which and from which no recording and no reproduction of data are caused respectively, said guard areas being formed before and after a boundary between said data read-only area and said data recording/reproducing area;

• said system comprising:
• track search means for searching a target track by a rough searching and a fine searching;
• detecting means for detecting said data field identification flag of an addressed sector, and
• control means for controlling writing and reading of data, the number of tracks of said guard area being set equal to or greater than a maximum number of tracks constituting a possible search error which corresponds to a difference between a target track in the rough searching and a track at the time of completion of the rough searching performed by said track search means, in order to prevent said control means from recording and reproducing data in said guard area.