第1题:
You are signing on a deck officer,who will be designated as one of the GMDSS operators,before sailing foreign.Which statement is TRUE ________.
A.He/she must have an STCW certificate endorsed as“Valid for Service on Vessels Operating in the GMDSS System”
B.He/she must present either an FCC-issued license or a Coast Guard-issued license
C.You must consult the“List of Qualifications”on the reverse of his/her FCC-issued license
D.His/her Merchant Mariners Document must have an added endorsement as “Radio Electronics Officer”
第2题:
第3题:
在生产者/消费者问题中,用s表示互斥信号量,e表示空缓冲区资源信号量,n表示满缓冲区资源信号量,下列生产者和消费者的操作(生产者和消费者可并发执行),可能产生死锁的是()。
A.生产者:wait(s); wait(e); append(); signal(n); signal(s);消费者: wait(s); wait(n); take(); signal(e); signal(s);
B.生产者:wait(s); wait(e); append(); signal(n); signal(s);消费者: wait(n); wait(s); take(); signal(s); signal(e);
C.生产者:wait(e); wait(s); append(); signal(s); signal(n);消费者: wait(s); wait(n); take(); signal(e); signal(s);
D.生产者:wait(e); wait(s); append(); signal(s); signal(n);消费者: wait(n); wait(s); take(); signal(s); signa
第4题:
第5题:
在生产者/消费者问题中,用s表示实施互斥的信号量,e表示与缓冲区空闲空间数量相关的信号量,n表示与缓冲区中数据项个数相关的信号量,下列生产者和消费者的操作(生产者和消费者可并发执行),可能产生死锁的是()。
A.生产者:wait(s); wait(e); append(); signal(n); signal(s);消费者: wait(s); wait(n); take(); signal(e); signal(s);
B.生产者:wait(s); wait(e); append(); signal(n); signal(s);消费者: wait(n); wait(s); take(); signal(s); signal(e);
C.生产者:wait(e); wait(s); append(); signal(s); signal(n);消费者: wait(s); wait(n); take(); signal(e); signal(s);
D.生产者:wait(e); wait(s); append(); signal(s); signal(n);消费者: wait(n); wait(s); take(); signal(s); signa