Final answer:
When designing control procedures for a computer system, it is important to build them into the system as it is designed and consider the costs and benefits. Control procedures should be implemented based on the level of risk and impact on the system.
Step-by-step explanation:
When designing control procedures for a computer system, it is important to consider several factors. One of the key points is that control procedures should be built into the system as it is designed. This means that control measures should be integrated into the system architecture and functionality from the beginning. By doing so, it becomes easier to ensure the security and integrity of the system.
Implementing control procedures after the system is functioning properly (option b) may introduce vulnerabilities and make it more difficult to maintain a secure environment. Control procedures are not irrelevant (option a), as they play a crucial role in safeguarding the system and its data. However, it is essential to carefully consider the costs and benefits associated with implementing control procedures, as they should be prioritized based on the level of risk and impact on the system.