Hello friends.welcome to GeeksforGeeks .today
we are going to learn worst fit algorithm for
memory management. What is worst fit.Worst Fit allocates a process
to the partition which is largest sufficient among
the freely available partitions available in the main memory.
Given block sizes and process size we need to find which block is assigned to which process
under worst fit algorithm. This will be Input i.e block_sizes and process
sizes.and your output should be like this Now let’s look at the implementation
1- Input memory blocks and processes with sizes.
2- Initialize all memory blocks as free. 3- Start by picking each process and find
the Maximum block size that can be assigned to
current process i.e., you have to find the maximum of all the blocks that could be assigned
to a process
, if found then assign it to the current process.
5- If not then leave that process and keep checking
the further processes. Block size is 100,500,200,300,600
Processes size is 212,417,112,426 According to the code in the article we will
see how this example proceeds. N is number of processes which is 4 and m
is number of available blocks which are 5.let allocation be an array of size 4 and initialized
with all -1. i=0 process size=212,
Block with size 500,300,600 can be allocated to this process maximum among them is 600
so worst fit block size would be 600 so allocation=4
which is the index of the block 600 blocksize=600-212=388
Now this block has space 388 i=1 process size=417,worst fit=500 so allocation
becomes 1 blocksize-=417 which is 83. Now available block sizes are 100 83 200 300
388 When i=2 process size=112,so 200,300,388 can
be allocated to this process but maximum among them is 388 so worst fit block size=388
so allocation=4 block size-=112 so which is
276 Now this block has space 276 when i=3 process
size=426,here no block is greater than or
equal to 426 worst fit not available so allocation remains -1
At last allocation array will be like this 4 1 4 -1 and the output should be this.
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