When Processes need to share one source, they must run without disturbing each other knowing only one process can use a source. To do so the Critical Section(CS) concept has been developed. One of wel known CS algorithms is Bakery Algorithm.

Bakery Algorithm for n Processes

Before entering C.S. a process is given a number. A process having minimum number enters into C.S.  if P_i and P_j has same number and i<j then P_i enters C.S. in first order. Otherwise P_j enters C.S.

Number giving is always in increasing order (i.e.1,2,3,3,3,3,4,5…).


max (a₀,…, a_n-1) : is the biggest number in number[n] for P_i.
 

boolean choosing[n]; // initially “false”

int number[n]; // initially “0”

do

{

choosing[i] = true;

number[i] = max(number[0], number[1], …, number [n – 1])+1;

choosing[i] = false;

for (j = 0; j < n; j++)

{

while (choosing[j]) ;

while ((number[j] != 0) && (number[j] < number[i])) ;

}

CRITICAL SECTION

number[i] = 0;

REMAINDER SECTION

} while (1); // exit when false 

 
Is Bakery Algorithm Convenient?