help2002

It's UWAweek 42 (2nd semester, week 12)

help2002

This forum is provided to promote discussion amongst students enrolled in CITS2002 Systems Programming.
Please consider offering answers and suggestions to help other students! And if you fix a problem by following a suggestion here, it would be great if other interested students could see a short "Great, fixed it!" followup message.

Displaying selected article

Showing 1 of 738 articles.
Currently 48 other people reading this forum.

UWA week 42 (2nd semester, week 12) ↓

2nd project Output verification (all 12)

4:33pm Tue 15th Oct, Joshua N.

ANONYMOUS wrote:

> How come it is correct, if the replacement is ignored? > Because in the example in the given input last sequence of numbers are "1 1 2 2 3 3 2 2 1 1" and because of that all the pages of process 0 will definitely be replaced by the new pages of all the other processes right? my input and output is as follows > > in.txt > > 0 0 0 0 0 1 1 2 2 3 3 2 2 1 1 > > out.txt > > Process 0 : 99 99 99 99 > Process 1 : 5 99 4 99 > Process 2 : 6 7 2 3 > Process 3 : 0 1 99 99 > 0,3,9; 0,3,9; 1,3,10; 1,3,10; 2,2,11; 2,2,11; 3,2,12; 3,2,12; 2,1,13; 2,1,13; 0,1,14; 0,1,14; 0,2,7; 0,2,7; 1,2,8; 1,2,8;

This isn't correct because we are using the "Local" Least Recently Used (LRU) algorithm to evict processes. You seem to be using "global". 1. At time 0,1,2,3: 0 0 0 0 is loaded. 2. At time 4: The fifth zero is ignored. 3. At time 5,6,7,8: 1 1 2 2 is loaded. RAM is now full. 4. Since RAM is full we need to evict a process to make room for 3, but no page of 3 is currently on RAM so we need to use "global" LRU instead of "local". 5. At time 9: The first 0 on RAM is evicted and replaced with 3. 6. At time 10: The next 3 is loaded and replaces the other 3 ("local" LRU). 7. At time 11, 12: 2 2 replaces the 2's currently in RAM ("local" LRU). 8. At time 13, 14: 1 1 replaces the 1's currently in RAM ("local" LRU). so in the end the contents of RAM are: 3,1,10; 3,1,10; 0,1,1; 0,1,1; 0,2,2; 0,2,2; 0,3,3; 0,3,3; 1,2,13; 1,2,13; 1,3,14; 1,3,14; 2,2,11; 2,2,11; 2,3,12; 2,3,12;