Name: 张 海
练习8 (第12、13章)
#1 Points possible: 2
Which of the following storage device does not belong to the tertiary storage structure?
CD-ROM DVD Hard disks Tapes
#2 Points possible: 2
Which provides high reliability inexpensively?
RAID 0 RAID 2 RAID 4 RAID 5
#3 Points possible: 2
Which kind of swap space is fastest?
A swap file on FAT A swap file on ext3
A partition with sophisticated file system functions A raw partition
#4 Points possible: 2
UNIX treats I/O devices as ______.
regular files directory files indexed files special files
#5 Points possible: 2
_______ present a uniform device-access interface to the I/O subsystem, much as system calls provide a standard interface between the application and the operating system.
Kernel
Device drivers Bus
Operating system
#6 Points possible: 2
The I/O control of disk devices mainly adopt following method.
polled interrupt channel DMA
#7 Points possible: 2
Disk access time does not include _____ .
seek time
rotational latency time read/write time
CPU scheduling time
#8 Points possible: 2
__________ is used to cope with the speed mismatch between CPU and I/O devices.
Buffering parallel caching semaphore
#9 Points possible: 2
In the disk scheduling algorithm, which algorithm may change the arm’s movement direction at any moment?
C-SCAN SSTF SCAN
none of the above
#10 Points possible: 0
45、（7分）假设计算机系统采用CSCAN（循环扫描）磁盘调度策略，使用2KB的内 存空间记录16384个磁盘块的空闲状态。
（1） 请说明在上述条件下如何进行磁盘块空闲状态管理。
（2） 设某单面磁盘旋转速度为每分钟6000转。每个磁道有100个扇区，相邻磁道 间的平均移动时间为1ms。若在某时刻，磁头位于100号磁道处，并沿着磁道号增 大的方向移动（如下图所示），磁道号请求队列为50、90、30、120，对请求队列 中的每个磁道需读取1个随机分布的扇区，则读完这4个扇区总共需要多少时间？要 求给出计算过程。
（3）如果将磁盘替换为随机访问的Flash半导体存储器（如U盘、SSD等），是否有 比CSACN更高效的磁盘调度策略？若有，给出磁盘调度策略的名称并说明理由；若 无，说明理由。
