operating system...

1. What is the difference between external  and internal fragmentation?

_________________________________________________________________________________________ 

_________________________________________________________________________________________ 

1. Given five memory partitions of 100 KB, 400 KB, 200 KB, 300 KB, and 700 KB (in order), how would each of the first-fit, best-fit, and worst-fit algorithms place processes of 312 KB, 217 KB, 112 KB, and 426 KB ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

_________________________________________________________________________________________________________________________________________________________________________________

1. Consider a computer system with a 32-bit logical address and 2-KB page size. The system supports up to 256 MB of physical memory. How many entries are there in a conventional page table? Explain your answer.

_________________________________________________________________________________________ 

_________________________________________________________________________________________ 

_________________________________________________________________________________________ 

_________________________________________________________________________________________ 

1. Consider a paging system with the page table stored in memory. 
1. If a memory reference takes 120 nanoseconds, how long does a paged memory reference take? Explain your answer.

_________________________________________________________________________________________ 

_________________________________________________________________________________________

1. If we add TLBs, and 70% of all page-table references are found in the TLBs, what is the effective memory reference time? (Assume that finding a page-table entry in the TLBs takes zero time, if the entry is there.) ______________________________________________________________________ 

_________________________________________________________________________________________ 

_________________________________________________________________________________________