Consider the following schedules which include the beginning operations start events. What happens as each executes under the basic timestamp based concurrency protocol.

$(1)$ s$1$ r$1($a$)$ s$2$ w$2($b$)$ r$2($a$)$ w$1($b$)$

$(2)$ s$1$ s$2$ r$1($a$)$ r$2($b$)$ w$2($a$)$ w$1($b$)$