In the same way that a library uses the basement to store books that do not fit in the stacks, computer systems use the main memory to store data that does not fit in hard drive

The hard drive provides an illusion of more capacity than exists in the main memory called

Data in virtual memory takes a short time to access

The Main memory/Physical memory can be viewed as a cache for the most commonly used data from the hard drive

Virtual memory increases the memory capacity by using a hard drive to store data that does not fit in the main memory

Caches and virtual memory add complexity and hardware to a computer system, but the benefits usually outweigh the costs

All modern personal computers doesn’t use caches and virtual memory

Most processors also use the memory interface to communicate with I/O devices.This is called memory-mapped I/O

The percentage of memory accesses not found in a given level of memory

The percentage of memory accesses found in a given level of memory

the average time a processor must wait for memory per load or store instruction

In the typical computer system, the processor first looks for the data in the cache. If the cache misses, the processor then looks in main memory. If the main memory misses, the processor accesses virtual memory on the hard disk

the access times of the virtual memory

the main memory miss rates

the cache miss rates

the access times of the main memory

the access times of the cache

AMAT =

Access time is measured by cycles

Miss Rate is measured by percentage

An 11-cycle average memory access time means that the processor spends …. cycles waiting for data for every … cycle actually using that data