When an online computer system is in use, internal control can be strengthened by

a. Providing for the separation of duties between data input and error listing operations.

b. Attaching plastic file protection rings to reels of magnetic tape before new data can be entered on the file.

c. Making a validity check of an identification number before a user can obtain access to the computer files.

d. Preparing batch totals to provide assurance that file updates are made for the entire input.