Patent ID: 7602686

Claim:
A simultaneous recording and reproduction method for recording a first real time data in an information recording medium while reproducing a second real time data recorded in the information recording medium, comprising the steps of: searching for unallocated areas on the information recording medium and allocating at least one unallocated area, wherein the at least one unallocated area has a size which is greater than or equal to a minimum size Y, as an area in which the first real time data is to be recorded; selecting at least one area in which the selected at least one area includes a non-used area having a size which is less than or equal to a predetermined size of L from among the allocated at least one area, wherein the non-used area is an area which is not used during the recording operation or the reproduction operation, L denotes the size of non-used area which is allowed within a scale having a size which is less than or equal to 1/N of the minimum size Y and N denotes an integer which is greater than or equal to two; recording the first real time data in the selected at least one area; and reading the second real time data from at least one area in which the second real time data has been recorded, whereby each of the at least one area has a size which is greater than or equal to the minimum size Y, wherein the minimum size Y is determined to enable the simultaneous recording and reproduction, even if an (N+1) number of non-used areas each having a size of L exists within two adjacent areas where data is to be recorded during the recording operations immediately before and immediately after an access operation, or even if the (N+1) number of non-used areas having a size of L exists within two adjacent areas where data is to be read during the reproduction operations immediately before and immediately after an access operation.