COMP SYNC aligns an item to the natural boundaries, it will be synchronized right and left. If we use binary items that are found at the boundaries of words in memory, these ones have a more rapid address resolution. The size of WORD from mainframe memory is four bytes. So every word has to BEGIN from an address which is divisible by four. When the primary variable is x(3) and the next ONE is s9(4) comp if the Sync clause is not specified, the second variable will begin from byte 3. When Sync is specified the beginning address will be 4; this more rapid, even if we may notice a little waste of memory.

COMP SYNC aligns an item to the natural boundaries, it will be synchronized right and left. If we use binary items that are found at the boundaries of words in memory, these ones have a more rapid address resolution. The size of word from mainframe memory is four bytes. So every word has to begin from an address which is divisible by four. When the primary variable is x(3) and the next one is s9(4) comp if the Sync clause is not specified, the second variable will begin from byte 3. When Sync is specified the beginning address will be 4; this more rapid, even if we may notice a little waste of memory.