Operating System Set 8 (30 mcqs)

1. I/O hardware contains
a) bus
b) controller
c) I/O port and its registers
d) all of the mentioned

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

3. The host sets _____ bit when a command is avialable a command is avialable for the controller to execute.
a) write
b) status
c) command-ready
d) control

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

5. Device drivers are implemented to interface
a) character devices
b) block devices
c) network devices
d) all of the mentioned

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

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

8. Which buffer holds the output for a device?
a) spool
b) output
c) status
d) magic

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

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

11) RAID level 3 supports a lower number of I/Os per second, because _______________.
a) every disk has to participate in every I/O request
b) only one disk participates per I/O request
c) I/O cycle consumes a lot of CPU time
d) All of these

12) RAID level _____ is also known as block interleaved parity organisation and uses block level striping and keeps a parity block on a seperate disk.
a) 1
b) 2
c) 3
d) 4

13) A performance problem with _________ is the expense of computing and writing parity.
a) non-parity based RAID levels
b) parity based RAID levels
c) all RAID levels
d) None of these

14) In RAID level 4, one block read, accesses __________.
a) only one disk
b) all disks simultaneously
c) all disks sequentially
d) None of these
.
15) The overall I/O rate in RAID level 4 is :
a) low
b) very low
c) high
d) None of these

16) A write of a block has to access : (choose all that apply)
a) the disk on which the block is stored
b) parity disk
c) a parity block
d) All of these

17) RAID level 5 is also known as :
a) bit-interleaved parity organization
b) block-interleaved parity organization
c) block-interleaved distributed parity
d) memory-style ECC organization

18) RAID level ____ spreads parity and data among all N+1 disks rather than storing data in N disks and parity in 1.
a) 3
b) 4
c) 5
d) 6

19) The potential overuse of a single parity disk is avoided in RAID level ____.
a) 3
b) 4
c) 5
d) All of these

20) RAID level 0+1 is used because, RAID level 0 provides ______ whereas RAID level 1 provides ________.
a) performance, redundancy
b) performance, reliability
c) redundancy, performance
d) None of these

21) What are the characteristics of tightly coupled system ? (Choose three)
a) Same clock, usually shared memory
b) Communication is via this shared memory
c) Multiprocessors
d) Different clock

22) What are the characteristics of tightly coupled system ? (Choose three)
a) Different clock
b) Use communication links
c) Same clock
d) Distributed systems

23) What are the characteristics of mutual exclusion using centralized approach ? (Choose three)
a) One processor as coordinator which handles all requests
b) It requires request,reply and release per critical section entry
c) The method is free from starvation
d) When responses are received from all processes, then process can enter its Critical Section

24) What are the characteristics of fully distributed approach ? (Choose two)
a) When responses are received from all processes, then process can enter its Critical Section
b) When process exits its critical section, the process sends reply messages to all its deferred requests.
c) It requires request,reply and release per critical section entry
d) One processor as coordinator which handles all requests

25) What are the advantages of token(with rings) passing approach ? (Choose three)
a) One processor as coordinator which handles all requests
b) No starvation if the ring is unidirectional
c) There are many messages passed per section entered if few users want to get in section
d) One processor as coordinator which handles all requests
e) Only one message/entry if everyone wants to get in

26) What is the characteristics of atomicity ?
a) All operations associated are executed to completion or none are performed
b) One processor as coordinator which handles all requests
c) When responses are received from all processes, then process can enter its Critical Section
d) Use communication links

27) What things are transaction coordinator is responsible for ? (Choose three)
a) Starting the execution of the transaction
b) Breaking transaction into a number of subtransactions
c) Coordinating the termination of the transaction
d) Syncronization of the parties

28) Single coordinator approach has the following advantages : (Choose two)
a) Simple implementation
b) Simple deadlock handling
c) Speed of operation
d) No bottleneck

29) Single coordinator approach has the following disadvantages : (Choose two)
a) Bottleneck
b) Slow response
c) Vulnerability
d) One request per second

30) What are the disadvantages of majority protocol ? (Choose two)
a) Complicated implementation
b) Deadlock can occur easily
c) Bottleneck
d) Vulnerability

Answers
1-d 2-a 3-c 4-d 5-d
6-a 7-d 8-a 9-a 10-b
11-a 12-d 13-b 14-a 15-c
16-d 17-c 18-c 19-c 20-a
21-a,b,c 22-abd 23-abc 24-ab 25-abd
26-a 27-abc 28-ab 29-ac 30-ab

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