Question

(15 points) Consider a swapping system in which memory consists of the following hole sizes in memory order: 16K, 14K, 4K, 20K, 18K, 7K, 9K, 12K, and 15K. Which hole is taken for successive segment requests of (a) 12K (b) 10K (c) 9K for first fit? Now repeat the question for best fit, worst fit, and next fit

Answer 1

first fit: for every segment to allocate hole ,searching of holes from starting until find hole size greater than or equal to segment.(note: hole should not be allocated before with other segment)

above problem:first fit

s.no segment hole

a)    12k ---> 16k

b) 10k ---> 14k

c) 9k ---> 20k

best fit: for every segment to allocate hole, searching of holes from starting until find minimum hole size greater than or equal to segment.  (note: hole should not be allocated before with other segment)

above problem: best fit

s.no segment hole

a)    12k ---> 12k

b) 10k ---> 14k

c) 9k ---> 9k  

worst fit: for every segment to allocate hole, searching of holes from starting until find maximum hole size greater than or equal to segment.(note: hole should not be allocated before with other segment)

above problem : worst fit

s.no segment   hole

a) 12k ---> 20k

b) 10k ---> 18k

c) 9k ---> 15k

next fit: it is also like as first fit. For every segment to allocate a hole, searching of holes starts next from last allocated hole

above problem:

   s.no segment hole

a) 12k ---> 16k

b) 10k ---> 14k

c) 9k ---> 20k