When auditing an EDP accounting system, the independent auditor should have a general familiarity with the effects of the use of EDP on the various characteristics of accounting control and on the auditor's study and evaluation of such control. The independent auditor must be aware of those control procedures that are commonly referred to as "general" controls and those that are commonly referred to as "application" controls. General controls relate to all EDP activities and application controls relate to specific accounting tasks.

Required:

a. What are the general controls that should exist in EDP-based accounting systems?

b. What are the purposes of each of the following categories of application controls?
1. Input controls.
2. Processing controls.
3. Output controls.