[1]in which引出的定语从句修饰cases，从句中又由such that引出状语从句，此从句中主语为sharing the bus．
[2]将损失很多（毫秒的）时间．
[3]264MB/s折算为数据传输速率为264×8Mb/s=2．112Gb/s．
[4]DRAM：动态随机存储器。bridge实为缓冲器，见下句．
[5]yet作“并”解，由yet引出另一个并列句．
EXERCISES
1．True / False．
（1）______ A general-purpose bus is point-to-point between two physical devices．
（2）______Dedicated buses are used of special high-bandwidth applications．
（3）______ Many users on a general-purpose bus can share the same bus simultaneously．
（4）______ The difference between centralized and decentralized control is to grant or not grant a device access to the bus．
（5)______According to this text，decentralized control is the same as distributed control．
（6）______The clock rate of asynchronous communication is limited．
（7）______PCI is designed to support single processor system only．
（8）______ PCI bridge acts as a buffer．
（9）______ A disk controller has a receiver only．
（10）______ A dedicated bus needs address 1ines．
2．Fill in the blanks．
（1）In a computer system the bus is used to pass______between its components．
（2）The current standard of PCI allows the use of up to______．
（3）We can classify the buses by ______．
（4）When we hope short latent time and high bandwidth of a bus，we should choice______.
（5）Synchronous communication needs a common______while asynchronous communication doesn’t need．
（6）All devices in a centralized control are treated equally except for their ______．
（7）If a disk is unable to read，the system performance will be______．
（8）Centralized controllers have at least three types______．
（9）Asynchronous transmission can get the fastest______and smallest______．
（10）In a typical server system we can find two types of bus，they are______．
a．64 data lines
b．priority for bus access
c．dedicated bus
d．system bus，PCI bus
e．daisy chain，polling with a global counter，and polling with local counters
f．data rate，delay
g．clock
h．lost
i．address，instruction，and data
j．purpose，control，and communication technique
1.（1）f（2）t（3）t（4）f（5）t（6）f（7）f（8）t（9）f（10）f
2.（1）i（2）a（3）j（4）c（5）g（6）b（7）h（8）e（9）f（10）d