Algorithm 2

• Shared variables

1. boolean flag[2];
2. initially flag [0] = flag [1] = false.
3. flag [i] = true Þ Pi ready to enter its critical section

• Process Pi

  do {

  flag[i] := true;
  while (flag[j]) ;  critical section

  flag [i] = false;

  remainder section

  } while (1);

• Satisfies mutual exclusion, but not progress requirement.