Briefly describe concurrency execution?
Lock - based protocols
Locks
There are several modes in which a data item may be locked in this section we restrict our attention to two modes
Ø Shared
Ø Exclusive
T1 : lock - x(B );
read(B);
B:=B-50;
write(B);
unlock(B);
Lock-x(A);
read(A);
A:=A+50;
write(A);
unlock(A).