Items should be aligned for maximum efficiency. The best alignment for data items depends on their size. Aligned data items can be handled more efficiently at machine code level; by default, the ALIGN directive will do this. See the table in the ALIGN directive for more information.
To ensure that all items in a table are correctly aligned, check that the size of an occurrence in the table is a multiple of two or four bytes as required. Pad the table as necessary. For example, in the following table, a three-byte filler has been added to each occurrence in the table to ensure that the numeric data item is always aligned on a four-byte boundary:
01 a OCCURS 10.
03 b PIC X(4) COMP-5
03 c PIC X.
03 filler PIC X(3).
You can use the REF Compiler directive to find out how data items are aligned.