1. I/O hardware contains ____________
a) Bus
b) Controller
c) I/O port and its registers
d) All of the mentioned
Answer: d
Explanation: None.
2. The data-in register of I/O port is ____________
a) Read by host to get input
b) Read by controller to get input
c) Written by host to send output
d) Written by host to start a command
Answer: a
Explanation: None.
3. The host sets _____ bit when a command is available for the controller to execute.
a) write
b) status
c) command-ready
d) control
Answer: c
Explanation: None.
4. When hardware is accessed by reading and writing to the specific memory locations, then it is called ____________
a) port-mapped I/O
b) controller-mapped I/O
c) bus-mapped I/O
d) none of the mentioned
Answer: d
Explanation: It is called memory-mapped I/O.
5. Device drivers are implemented to interface ____________
a) character devices
b) block devices
c) network devices
d) all of the mentioned
Answer: d
Explanation: None.
6. Which hardware triggers some operation after certain programmed count?
a) programmable interval timer
b) interrupt timer
c) programmable timer
d) none of the mentioned
Answer: a
Explanation: None.
7. The device-status table contains ____________
a) each I/O device type
b) each I/O device address
c) each I/O device state
d) all of the mentioned
Answer: d
Explanation: None.
8. Which buffer holds the output for a device?
a) spool
b) output
c) status
d) magic
Answer: a
Explanation: None.
9. Which one of the following connects high-speed high-bandwidth device to memory subsystem and CPU.
a) Expansion bus
b) PCI bus
c) SCSI bus
d) None of the mentioned
Answer: a
Explanation: None.
10. A process is moved to wait queue when I/O request is made with ____________
a) non-blocking I/O
b) blocking I/O
c) asynchronous I/O
d) synchronous I/O
Answer: b
Explanation: None.
11. In _______ information is recorded magnetically on platters.
a) magnetic disks
b) electrical disks
c) assemblies
d) cylinders
Answer: a
Explanation: None.
12. The heads of the magnetic disk are attached to a _____ that moves all the heads as a unit.
a) spindle
b) disk arm
c) track
d) none of the mentioned
Answer: b
Explanation: None.
13. The set of tracks that are at one arm position make up a ___________
a) magnetic disks
b) electrical disks
c) assemblies
d) cylinders
Answer: d
Explanation: None.
14. The time taken to move the disk arm to the desired cylinder is called the ____________
a) positioning time
b) random access time
c) seek time
d) rotational latency
Answer: c
Explanation: None.
15. The time taken for the desired sector to rotate to the disk head is called ____________
a) positioning time
b) random access time
c) seek time
d) rotational latency
Answer: d
Explanation: None.
16. When the head damages the magnetic surface, it is known as _________
a) disk crash
b) head crash
c) magnetic damage
d) all of the mentioned
Answer: b
Explanation: None.
17. A floppy disk is designed to rotate ___________ as compared to a hard disk drive.
a) faster
b) slower
c) at the same speed
d) none of the mentioned
Answer: b
Explanation: None.
18. What is the host controller?
a) controller built at the end of each disk
b) controller at the computer end of the bus
c) all of the mentioned
d) none of the mentioned
Answer: b
Explanation: None.
19. ______ controller sends the command placed into it, via messages to the _____ controller.
a) host, host
b) disk, disk
c) host, disk
d) disk, host
Answer: c
Explanation: None.
20. What is the disk bandwidth?
a) the total number of bytes transferred
b) total time between the first request for service and the completion on the last transfer
c) the total number of bytes transferred divided by the total time between the first request for service and the completion on the last transfer
d) none of the mentioned
Answer: c
Explanation: None.
21. Whenever a process needs I/O to or from a disk it issues a ______________
a) system call to the CPU
b) system call to the operating system
c) a special procedure
d) all of the mentioned
Answer: b
Explanation: None.
22. If a process needs I/O to or from a disk, and if the drive or controller is busy then ____________
a) the request will be placed in the queue of pending requests for that drive
b) the request will not be processed and will be ignored completely
c) the request will be not be placed
d) none of the mentioned
Answer: a
Explanation: None.
23. Consider a disk queue with requests for I/O to blocks on cylinders.
98 183 37 122 14 124 65 67
Considering FCFS (first cum first served) scheduling, the total number of head movements is, if the disk head is initially at 53 is?
a) 600
b) 620
c) 630
d) 640
Answer: d
Explanation: None.
24. Consider a disk queue with requests for I/O to blocks on cylinders.
98 183 37 122 14 124 65 67
Considering SSTF (shortest seek time first) scheduling, the total number of head movements is, if the disk head is initially at 53 is?
a) 224
b) 236
c) 245
d) 240
Answer: b
Explanation: None.
25. Random access in magnetic tapes is _________ compared to magnetic disks.
a) fast
b) very fast
c) slow
d) very slow
Answer: d
Explanation: None.
26. Magnetic tape drives can write data at a speed ________ disk drives.
a) much lesser than
b) comparable to
c) much faster than
d) none of the mentioned
Answer: b
Explanation: None.
27. On media that use constant linear velocity (CLV), the _____________ is uniform.
a) density of bits on the disk
b) density of bits per sector
c) the density of bits per track
d) none of the mentionedAnswer: c
Explanation: The farther a track is from the center of the disk.
28. SSTF algorithm, like SJF __________ of some requests.
a) may cause starvation
b) will cause starvation
c) does not cause starvation
d) causes aging
Answer: a
Explanation: None.
29. In the ______ algorithm, the disk arm starts at one end of the disk and moves toward the other end, servicing requests till the other end of the disk. At the other end, the direction is reversed and servicing continues.
a) LOOK
b) SCAN
c) C-SCAN
d) C-LOOK
Answer: b
Explanation: None.
30. In the _______ algorithm, the disk head moves from one end to the other, servicing requests along the way. When the head reaches the other end, it immediately returns to the beginning of the disk without servicing any requests on the return trip.
a) LOOK
b) SCAN
c) C-SCAN
d) C-LOOK
Answer: c
Explanation: None.
31. In the ______ algorithm, the disk arm goes as far as the final request in each direction, then reverses direction immediately without going to the end of the disk.
a) LOOK
b) SCAN
c) C-SCAN
d) C-LOOK
Answer: a
Explanation: None.
32. The process of dividing a disk into sectors that the disk controller can read and write, before a disk can store data is known as ____________
a) partitioning
b) swap space creation
c) low-level formatting
d) none of the mentioned
Answer: c
Explanation: None.
33. The data structure for a sector typically contains ____________
a) header
b) data area
c) trailer
d) all of the mentioned
Answer: d
Explanation: None.
34. The header and trailer of a sector contain information used by the disk controller such as _________ and _________
a) main section & disk identifier
b) error correcting codes (ECC) & sector number
c) sector number & main section
d) disk identifier & sector number
Answer: b
Explanation: None.
35. The two steps the operating system takes to use a disk to hold its files are _______ and ________
a) partitioning & logical formatting
b) swap space creation & caching
c) caching & logical formatting
d) logical formatting & swap space creation
Answer: a
Explanation: None.
36. The _______ program initializes all aspects of the system, from CPU registers to device controllers and the contents of main memory, and then starts the operating system.
a) main
b) bootloader
c) bootstrap
d) rom
Answer: c
Explanation: None.
37. For most computers, the bootstrap is stored in ________
a) RAM
b) ROM
c) Cache
d) Tertiary storage
Answer: b
Explanation: None.
38. A disk that has a boot partition is called a _________
a) start disk
b) end disk
c) boot disk
d) all of the mentioned
Answer: c
Explanation: None.
39. Defective sectors on disks are often known as __________
a) good blocks
b) destroyed blocks
c) bad blocks
d) none of the mentioned
Answer: c
Explanation: None.
40. In SCSI disks used in high end PCs, the controller maintains a list of _________ on the disk. The disk is initialized during ________ formatting which sets aside spare sectors not visible to the operating system.
a) destroyed blocks, high level formatting
b) bad blocks, partitioning
c) bad blocks, low level formatting
d) destroyed blocks, partitioning
Answer: c
Explanation: None.
41. The scheme used in the above question is known as _______ or ________
a) sector sparing & forwarding
b) forwarding & sector utilization
c) backwarding & forwarding
d) sector utilization & backwarding
Answer: a
Explanation: None.
42. An unrecoverable error is known as _________
a) hard error
b) tough error
c) soft error
d) none of the mentioned
Answer: a
Explanation: None.
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