Design Issues

Design Issues

1. local vs global

   • PFF
     • It tells when to increase or decrease a process' page allocation but says nothing about which page to replace on a fault.

2. load control

   • PFF indicates some processes needs more memory but no processes needs less memory. In this case, there is no way to give more memory to those processes needing it without hurting some other processes.
   • A good way to reduce the number of processes competing for memory is to swap some of them to the disk and free up all the pages they are holding

3. page size

4. separate instruction and data spaces