计算机考研操作系统统考历年真题答案2009-2015(2)

V(mutex1)

}

}

2015 23-27：A C D C C 28-30：A D D

45.Semaphore mutexA=1;

Semaphore mutexB=1;

Semaphore emptyA=M; Semaphore emptyB=N; Semaphore fullA=0; Semaphore fullB=0;

A{

While(TRUE){

P(fullA);

P(mutexA)

Get a mail from A_mailbox；

V(mutexA); V(fullA); Answer the question and raise aquestion;

P(emptyB);

P(mutexB)

send the mail to B；

V(mutexB);

V(emptyB);

}

}

B{

While(TRUE){

P(fullB);

P(mutexB)

Get a mail from B_mailbox；

V(mutexB);

V(fullB);

Answer the question and raise a question;

P(emptyA);

计算机考研统考真题

P(mutexA)

send the mail to A；

V(mutexA);

V(emptyA);

}