In the design and operation of an information system, three types of controls must be addressed—managerial controls, internal controls, and data or applica¬ tion controls. Managerial controls and internal controls are not unique to computer-based information systems. However, data or application controls are more specific to computerbased systems. Although many controls can be useful at more than one stage, specific data controls are usually categorized as input, processing, or output controls. 

Required

a. Explain the general purpose of

1. Input controls.

2. Processing controls.

3. Output controls.

b. Define and identify the objective of each of the following input controls:

1. Hash totals.

2. Limit checks.

3. Check digits.

c. Define and identify the objective of each of the following processing controls:

1. Sequence checks.

2. File identification.

3. Operating logs.

d. Define and identify the objective of the following output control:

1. Review by knowledgeable parties.