is not 0 when n 105 in other words l 106 is not the first block in a write this rule detects a tear in the write at l 105 the relevant blocks are highlighted in bold and also underlined an erroneous write is detected since rule 2 fails u2014 s n 1 lt s n and f n 1 is not equal to n n when n 105 in other words l 105 is not the last block in the write that started at lba n u2212 f n 104 this rule detects a tear in the write at l 105 in the case 3 the data on the storage subsystem will look like the relevant block write is highlighted in bold and also underlined again an erroneous write is detected since rule 2 fails u2014 s n 1 lt s n and f n 1 is not equal to n n when n 106 this rule would detect a tear in the write at l 106 in the case 4 the data on the storage subsystem will look like it might be thought that this erroneous write could be detected by the absence of any blocks with s n 34 being present on the storage subsystem this rule would detect a tear in the write at l 104 in fact performing a write read compare operation would detect any partial or complete tear anywhere in the write however if further writes are performed that overlay l 104 to l 108 then it is no longer possible to know if the write with s 34 was ever performed on the storage subsystem so the only way to detect a completely dropped write is to read the data back and check it for the presence.