Tranpose for quicker viewing

SAS can read very large data files indeed. But only the records that you are viewing are held in memory. This means that for two files of the same size, it takes much much longer to view the file with a few records but a large number of variables than a file with many records but only a few variables. (This is why you can have a number of records that is only limited by the size of your hard drive, but 'only' 32,768 variables.)
So the first thing to do if you have one of the former (for instance when using a two-dimensional array) is to transpose it into the latter.