Embedded Systems Design, 2nd Edition

284 Embedded systems design

allocation and when any virtual memory system needs to swap

memory blocks out to disk. The required software support is

usually performed by an operating system. In the latter case, if

system memory is very small compared with the virtual memory

size and application, the memory management driver will con-

sume a lot of processing power and time in simply moving data to

and from the disk. In extreme cases, this overhead starts to

dominate the system — which is working hard but achieving very

little. The addition of more memory relieves the need to swap and

releases more of the processing power to execute the application.

Finally, ...