Opt-out procedures can be confusing and time consuming, and they do not always work well.

You turn your computer on and nothing happens. The computer light is off. You check the fan and it is running. Which of the following can you assume?

A) The on/off button is malfunctioning. B) The outlet is supplying power. C) The motherboard is bad. D) There is no operating system installed.

Give an example of a schedule in which a pessimistic concurrency control makes a transaction wait but later allows it to commit, while an optimistic concurrency control restarts the transaction.

What will be an ideal response?