在一个使用循环调度的系统中，s表示执行进程切换所需要的时间，q表示循环的时间片，r表示进程在发生I/O阻塞前平均运行时间。(a)如果q=∞，CPU　效率是(31)；(b)如果q＞r，那么，CPU的效率是(32)；(c)s＜q＜r，CPU的效率是(33)；(d)s=q＜r，效率为(34)；(e)q几乎为零时，CPU的效率是(35)。

(65)

(63)

(64)

(62)

Network　managers　have　long　awaited　practical　voice-over-IP(VOIP)solutions.　VOIP　promises(71)network　management　and　decreases　costs　by(72)a　company's　telephony　and　data　infrastructures　into　one　network.　And　a　VOIP　solution　implemented　at　a　company'　s　head　-quarters　with　far　-reaching　branch　offices　can(73)tremendous　amounts　of(74)in　long　distance　phone　bills,　provided　that　solution　delivers　POTS　-like　voice(75)over　the　Internet.

(60)

(59)

(58)

(66)is a protocol that a host uses to inform. a router when it joins or leaves an Internet multicast group.

(67)is an error detection code that most data conlmunication networks use.

(68)is an interior gateway protocol that uses a distance vector algorithm to propagaterouting information.

(69)is a transfer mode in which all types of information are organized into fixed form. cells on all asynchronous or nonperiodic basis over a range of media.

(70)is an identifier of a web page.

(57)