Suppose that there are two types of philosophers. One type always picks up his left fork first (a €œlefty€), and the other type always picks up his right fork first (a €œrighty€). The behavior of a lefty is defined in Figure 6.12.

The behavior of a righty is as follows:
begin
repeat
think;
wait ( fork[ (i+1) mod 5] );
wait ( fork[i] );
eat;
signal ( fork[i] );
signal ( fork[ (i+1) mod 5] );
forever
end;
Prove the following:
a. Any seating arrangement of lefties and righties with at least one of each avoids deadlock.
b. Any seating arrangement of lefties and righties with at least one of each prevents starvation.

Transcribed Image Text:

program diningphilosoph ers */ semaphore fork [51 int ii void philosopher (int i) while (true) f think () wait (fork [i]) wait (fork [(i+1) mod 5]) eat ) signal (fork [ (i+1) mod 5]) signal (fork[i]) void main () parbegin (philosopher (0), philosopher (1), philosopher (2) philosopher (4)) philosopher (3)