8. A method of writing data to a linear tape data storage medium, said method comprising: arranging a block of user data into a data group of a logical array of data bytes, the array comprising a plurality of rows of said data bytes and a plurality of columns of said data bytes; applying error correction coding to individual ones of said rows, such that each of said rows is each arranged into four code words; in each of said rows, interleaving said four code words of the row, wherein in each of the rows, a first code word, a second code word, a third code word, and a fourth code word of the four code words are interleaved in an order of a portion of the first code word, a portion of the second code word, a portion of the third code word, and a portion of the fourth code word, and wherein the interleaved order of the portion of the first code word, the portion of the second code word, the portion of the third code word, and the portion of the fourth code word is repeated to perform the interleaving; writing said data group with the rows each having the interleaved code words as a single data track extending diagonally across the width of said tape data storage medium such that all of said data group is contained within said single data track extending across said width of said tape data storage medium.
8. A method of writing data to a linear tape data storage medium, said method comprising: arranging a block of user data into a data group of a logical array of data bytes, the array comprising a plurality of rows of said data bytes and a plurality of columns of said data bytes; applying error correction coding to individual ones of said rows, such that each of said rows is each arranged into four code words; in each of said rows, interleaving said four code words of the row, wherein in each of the rows, a first code word, a second code word, a third code word, and a fourth code word of the four code words are interleaved in an order of a portion of the first code word, a portion of the second code word, a portion of the third code word, and a portion of the fourth code word, and wherein the interleaved order of the portion of the first code word, the portion of the second code word, the portion of the third code word, and the portion of the fourth code word is repeated to perform the interleaving; writing said data group with the rows each having the interleaved code words as a single data track extending diagonally across the width of said tape data storage medium such that all of said data group is contained within said single data track extending across said width of said tape data storage medium. 13. The method as claimed in claim 8 , wherein said data are written to tape at a bit density in the range 6,220 to 6,614 bits/mm.