• on the first question I need some elaboration, listing out some characteristics is not enough.
• on the second question, some of you missed defining what is an external reference.
• computer performance did not double because of other hardware components that act as a bottle neck. software has nothing to do with hardware.
• I need some elaboration on methods of memory protection, listing bound registers and virtual memory without any explanation is not enough.
• I saw similar answers for three student, I will remind you that helping each other has some bounds, crossing these bounds is considered cheating.
•  the processor executes program instructions.
• hard drives, peripheral devices and tertiary storage devices are not required for a computer to execute program instructions.
• memory, register, and cache are all volatile storage.
• register, memory, cache all improve application performance.
• the only memory that can be referenced by a CPU is the register memory.

if any student feels that he/ she deserves another (higher) grade, feel free to stop by my office Monday from 11-1 or any time you see me my door open. by the way, I too make mistakes.