I have some problems with the application bestfit allocation dynamic partition in Bash and i want to know how do i create the bestfit algorithm that can work with blocks and processes and allocate by entering if a block fits?
I tried to launch it but i get some errors like command not found although i assigned my values.
I show you my whole program.
Thank you in advance
#!/bin/bash
# 1) Indroduction. Best-Fit program with bash.
echo "==================================================================================================="
echo "======= Welcome by Best-Fit program allocation. ======="
# ================================================================================================================
# 1.1) Declaration
declare -i numblocks
declare -i numprocess
declare -a blocksize=100
declare -a processsize=100
declare -i i
declare -i j
declare -a alloc=100
declare -a avail=100
declare -i min
# ================================================================================================================
# 2.2) Input Number of blocks.
echo -e "\nPlease enter the number of Blocks:"
# 2.2.1) Variable numblocks
read numblocks
# ================================================================================================================
# 1. For-Loop.
for ((i=1; i<=$numblocks; i ));
do
echo -e "\nPlease enter the $i. size of the block:"
read -a blocksize
echo -e "\nThe $i. blocksize is: ${blocksize[*]}"
done
# ================================================================================================================
# 2.2) Input Number of processes.
echo -e "\nPlease enter the number of processes "
# 2.2.1) Variable numprocess
read numprocess
# ================================================================================================================
# 2. For-Loop.
for ((i=1 ; i<=$numprocess; i ));
do
echo -e "\nPlease enter the $i. size of the process:"
read -a processsize
echo -e "\nThe $i. processsize is: ${processsize[*]}"
done
# ================================================================================================================
# Initialize alloc vector to -1 and avail to 9999.
for((i=0; i<$numprocess; i ));
do
alloc[i]=-1
done
for((i=0; i<$numblocks; i ));
do
avail[i]=9999
done
# ================================================================================================================
# Check for each process if a block is available.
for((i=0; i<$numprocess; i ));
do
for((j=0; j<$numblocks; j ));
do
if [ ${blocksize[j]} -gt ${processsize[i]} ]; # Problems. !!!!!!!! -gt means --> > (upper like)
then
avail[j]= ${blocksize[j]} - ${processsize[i]}
fi
done
done
# ================================================================================================================
min=0
for ((j=0; j<$numblocks; j ));
do
if [ ${avail[min]} -gt ${avail[j]} ];
then
min=$j
fi
done
# ================================================================================================================
alloc[i]= $min
if [ ${avail[$min]} -ge 9999 ];
then
alloc[i]=-1
fi
# ================================================================================================================
blocksize[min]=-1
# Initialize avail to 9999.
for ((j=0; j<$numprocess; j ));
do
avail[j]=9999
done
# ================================================================================================================
# Print the Output.
echo -e "\n================================ Results ================================"
for ((i=1; i<$numprocess; i ));
do
if [ ${alloc[i]} -ne -1 ];
then
echo "Process $i of ${processsize[*]} --> Block . ${alloc[*] }"
else
echo "Process $i of ${processsize[*]} --> is not allocated"
fi
done
CodePudding user response：
for ((i=1; i<=$numblocks; i ));
do
echo -e "\nPlease enter the $i. size of the block:"
read -a blocksize
echo -e "\nThe $i. blocksize is: ${blocksize[*]}"
done
This does not assign values to individual array elements. In each loop iteration, you're overwriting the entire array.
Demo:
for i in 1 2; do
printf '%d: ' $i
read -a blocksize
declare -p i blocksize
done
I enter "10" for i=1 and "20" for i=2:
1: 10
declare -- i="1"
declare -a blocksize=([0]="10")
2: 20
declare -- i="2"
declare -a blocksize=([0]="20")
Inside the loop, you need to
read -r "blocksize[$i]" # those quotes are necessary
CodePudding user response：
This Shellcheck-clean code is a Bash implementation for the example in Program for Best Fit algorithm in Memory Management - GeeksforGeeks:
#! /bin/bash -p
read -r -p 'Enter line of block sizes: ' -a block_sizes
read -r -p 'Enter line of process sizes: ' -a process_sizes
process_block_indexes=()
for pidx in "${!process_sizes[@]}"; do
psize=${process_sizes[pidx]}
best_block_idx='' best_block_size=''
for bidx in "${!block_sizes[@]}"; do
bsize=${block_sizes[bidx]}
(( psize > bsize )) && continue
if [[ -z $best_block_idx ]] || (( bsize < best_block_size )); then
best_block_idx=$bidx
best_block_size=$bsize
fi
done
[[ -z $best_block_idx ]] && continue
process_block_indexes[pidx]=$best_block_idx
block_sizes[best_block_idx]=$(( best_block_size - psize ))
done
echo 'Process No. Process Size Block no.'
for pidx in "${!process_sizes[@]}"; do
bidx=${process_block_indexes[pidx]-}
[[ -n $bidx ]] && bnum=$(( bidx 1 )) || bnum='Not Allocated'
printf 'd d s\n' \
"$(( pidx 1 ))" "${process_sizes[pidx]}" "$bnum"
done
Given the block list
100 500 200 300 600
and the process list
212 417 112 426 170 50 100 100
it produces the output
Process No. Process Size Block no.
1 212 4
2 417 2
3 112 3
4 426 5
5 170 5
6 50 2
7 100 1
8 100 Not Allocated