A method for compressing data, wherein said data are organized in at least one sector (Sector 0,..., Sector 15) comprising sector data being arranged in data blocks (Block 0,..., Block 2) and a sector trailer (Block 3), wherein each sector is separated from adjacent ones by a special sector separating character, and wherein each block within a sector is separated by a special block separating character, wherein the compressing method comprises: (a) searching for consecutive occurrences of same data values in the blocks of sector data wherein the blocks of the sector data are searched for occurrences of same data values throughout the whole block and every block detected that contains the same data value in all of its data elements is replaced by its data value, wherein it is defined as an additional rule that if at least two consecutive blocks contain the same data, then a first value following a block separating character indicates the data value and a second value indicates the number of consecutive blocks having only data of this value, followed by another block separating character, so that if the length of the data stream between two block separator characters is: 16: this block contains unpredictable data with no compression, 1: this block contains a series of 16 times the same value, for example 0x00 means the block is full of 0x00, 2: this and several following blocks contain the same value, for example 0x00 0x02 means that this block and the two following blocks are full of 0x00; and (b) searching for all different sector trailer values, thereby creating a sector trailer values table, which contains all different sector trailer values, and replacing the trailer of each sector by a reference to the respective one of the different sector trailer values contained in the sector trailer values table, thereby creating a sector index table, which defines for each sector which AD:SK:st sector trailer value of the sector trailer values table corresponds to the sector trailer of the respective sector. (a) searching for consecutive occurrences of same data values in the blocks of sector data wherein the blocks of the sector data are searched for occurrences of same data values throughout the whole block and every block detected that contains the same data value in all of its data elements is replaced by its data value, wherein it is defined as an additional rule that if at least two consecutive blocks contain the same data, then a first value following a block separating character indicates the data value and a second value indicates the number of consecutive blocks having only data of this value, followed by another block separating character, so that if the length of the data stream between two block separator characters is: 16: this block contains unpredictable data with no compression, 1: this block contains a series of 16 times the same value, for example 0x00 means the block is full of 0x00, 2: this and several following blocks contain the same value, for example 0x00 0x02 means that this block and the two following blocks are full of 0x00; and 16: this block contains unpredictable data with no compression, 1: this block contains a series of 16 times the same value, for example 0x00 means the block is full of 0x00, 2: this and several following blocks contain the same value, for example 0x00 0x02 means that this block and the two following blocks are full of 0x00; and (b) searching for all different sector trailer values, thereby creating a sector trailer values table, which contains all different sector trailer values, and replacing the trailer of each sector by a reference to the respective one of the different sector trailer values contained in the sector trailer values table, thereby creating a sector index table, which defines for each sector which AD:SK:st