Q. Consider the following sequence of memory reference from 460 words programs
10,11,104,170,73,309,185,245,246,434,364
a. give the reference string assuming page size of 100 words
b. find number of page faults using LRU assuming 200 words of primary memory.
Solution.
a.
Reference String assuming 100 words
1,1,2,2,1,4,1,2,3,3,5,5,4
b.
Using LRU
Page size=100 words
Primary memory=200 words
So no. of pages = 200/100=2
Thrashing
=========
CPU utilization for a process decreases if continuous swapping of memory takes place once the memory is full and there is no place for other program execution(thats where virtualization comes into existence).
File Structure
===========
1. Single Level File Structure
Example-> C:\>Program files
2. Double Level File Structure
Example-> C:>Program files>Microsoft
Similarly ....Multi level File access has many levels
File Access
=========
1. Sequential file Access
2. Index Sequential
3. Secondary Sequential
4. Direct File Access
File Allocation Methods
====================
1.Contiguous File Allocation
2.Linked File Allocation
3.Indexed File Allocation
Indexed File allocation is the most efficient file allocation because :
->direct memory access
->Least memory wastage
this ans isn't correct
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