一道关于数据库串行与调度的题

Sa: r1(x);w1(x);r2(x);w1(x);c2;c1
Sb: r1(x);w1(x);r2(x);w1(x);a2;c1
请问上面两个是可恢复调度吗
还有是冲突串行吗？

http://zhidao.baidu.com/link?url=uiYwuBzMsPll1EbYtxdGWSH1TlzHph46nP59qPpLb39aQjE9-mlvcEs_Elfv7mSkyn0N2jZE7Mqw4d3tDA9bJ1lJI45dHcjl8FBJD2n6u4u