Large ________ computers process transactions such as airline reservations, bank transactions, or registrations for students at a college.

The security administrator receives a service ticket saying a host based firewall is interfering with the operation of a new application that is being tested in delevopment. The administrator asks for clarification on which ports need to be open. The software vendor replies that it could use up to 20 ports and many customers have disabled the host based firewall. After examining the system the administrator sees several ports that are open for database and application servers that only used locally. The vendor continues to recommend disabling the host based firewall. Which of the following is the best course of action for the administrator to take?

A. Allow ports used by the application through the network firewall B. Allow ports used externally through the host firewall C. Follow the vendor recommendations and disable the host firewall D. Allow ports used locally through the host firewall

Assume that transactions are executed at REPEATABLE READ. Give an example in which a phantom occurs when a transaction executes a SELECT statement that specifies the value of the primary key in the WHERE clause.

What will be an ideal response?