Q1-Consider having the following reference string: 6 9 9 0 1 2 2 11 3 6 1 0 6 8

Q1-Consider having the following reference string:
6 9 9 0 1 2 2 11 3 6 1 0 6 8 1 2 6
Use FIFO, OPT, LRU page replacement algorithms and compare between them based on page faults, knowing that 4 pages can be in memory at a time per process.
Q2-Using below disk scheduling algorithms, illustrate the request queue (0-199) and compare between them.
99, 61, 112, 145, 23, 45, 65
Knowing that the Head pointer starts at 122.
FCFS
SCAN
C-SCAN
Q3-What are the types of memory fragmentation? How it could happen? and what is the worst dynamic memory allocation that can increase it?