This document contains a model question paper for the subject Operating Systems with 140 total marks. It has two parts: Part A contains one mark questions testing basic concepts and terms, and Part B contains two mark questions requiring explanations or short answers. The questions cover topics such as processes, memory management, file systems, I/O, and concurrency issues like deadlocks.

1. Model Question Paper
Subject Code: BC0042
Subject Name: Operating Systems
Credits: 4 Marks: 140
Part A (One mark questions)
1. sequence of instructions telling the computer what to do is called
a ---------------------
a) program
b)language
c) translator
d) package
2. A process is ------------------
a) program in main memory
b) Program in cache memory
c) program in secondary storage
d) program in execution

2. 3. A program to be executed must be in ---------------
a) main memory
b) secondary memory
c) virtual memory
d) Read only memory
4. ------------------ are very expensive and employed for specialized applications such as weather
forecasting
a) Micro computers
b) Super computers
c) Personal computers
d) Mainframe computers
5. In MS-DOS, the interfaces and levels of functionality are ---------------
a) not well separated.
b) well separated
c) independent
d) dependent
6. --------------------- approach simplifies debugging and system verification
a) Kernel
b) Layered
c) Extended
d) Virtual machine
7. In layered approach each layer uses the functions and services of ------------------
a) kernel
b) lower-level layers
c) higher-level layers

3. d) all of these
8. ------------------------------is a piece of computer software that isolates the application being used by the
user from the computer.
a) compiler
b) Modules
c)virtual machine
d) none of these
9. Using---------------- the file subsystem of Kernel mode is responsible for file and I/O management.
a) system calls
b) device drivers
c) modules
d) virtualization technique
10. A process may create a new process by executing --------------- system call
a) init
b) fork
c) create
d) new
11. A process control block contains varies attributes required by --------------------- to control a process
a) RAM
b) virtual memory
c) BIOS
d) Operating System
12. ------------- are popular way to improve application through parallelism
a) Processes

4. b) Threads
c) Context switching
d) none of these
13. ---------------is responsible for allocating primary memory to processes and for assisting the
programmer in loading and storing the contents of the primary memory.
a) Operating system
b) Memory manager
c)database administrator
d) RAM
14. ------------------------- refers to the technology in which some space in hard disk is used as an
extension of main memory.
a) cache memory
b) paging
c) virtual memory
d) paging
15. ------------- deals with when a modified page should be written out to secondary memory.
a) cleaning policy
b) fetch policy
c) frame locking
d) none of these
16. Microprocessors with small internal caches often employ the ---------------------------
mechanism
a) direct mapping
b) fully associative
c) set associative

5. d) sector mapping
17. ______________ selects a process from among the ready processes to execute on the CPU.
a) CPU Schedular
b) Loader
c) Dispatcher
d) Compiler
18. The time taken by the Dispatcher to stop one process and start another running is known as
_________________.
a) Turnaround time
b) Dispatch Latency
c) Access time
d) Response time
19. __________ systems are required to complete a critical task within a guaranteed amount of
time.
a) Virtual
b) soft real time
c) Hard Real time
d) None of these
20. A solution to starvation is _____________.
a) segmentation
b) Aging
c) Paging
d) virtual memory
21. When resources have multiple instances --------------- is used for deadlock Avoidance

6. a) Banker’s algorithm
b) Resource Allocation Graph
c) semaphores
d) all of these
22. ---------------------------- is a situation in which two computer programs sharing the same
resource are effectively preventing each other from accessing the resource, resulting in both
programs ceasing to function.
a) Semaphore
b) Deadlock
c) Mutual Exclusion
d) No preemption
23. ---------------------------------refers to a strategy where whenever a resource is requested, it is
only granted if it cannot result in deadlock.
a) Deadlock Prevention
b) Livelock
c) Deadlock avoidance
d) none of these
24. When a child dies, it sends a ------------------------ signal to its parent.
a) SIGCHLD
b) EDEADLK
c) WNOHANG
d) SEDECHLD
25. ------------------- occurs when two or more execution flows are able to run simultaneously.

7. a) Deadlock
b) Concurrency
c) race condition
d) interrupt
26. ----------------------- occurs when multiple processes or threads read and write data items so that
the final result depends on the order of execution of instructions in the multiple processes.
a) Race condition
b) Mutual exclusion
c) Exception
d) Interrupt
27. --------------- is a mechanism the prevents two or more processes from accessing a shared resource
simultaneously.
a) Livelock
b)Preemption
c) Semaphore
d) either a or b
28. In an interrupt driven system, context switches from one process to another can only occur on -------
-------------
a)predetermined time
b) interrupt
c) Busy waiting

8. d) all of these
29. In Multics, a process could have up to 256K segments, but each segment was limited to ---------------
64K words.
a) 64K
b) 32K
c) 1024K
d)112K
30 The problem with logical dumping is --------------
a) very costly
b) very slow
c) human errors
d) all of these
31. A two-byte integer called -------------- is interpreted as an index into an array of inodes in a
fixed, known location on disk.
a) an inode
b) an inumber
c) an imap
c) an imark
32. A variable sized block is called ---------------.
a) an extent
b) a segment
c) a page

9. d) a fragment
33. In ------------------ the disk drive itself has a way of discovering bad blockswith extremely high
probability.
a) disk index
b) Extents
c) Bad-block forwarding
d) back-up dumps
34. Because the I/O devices are not synchronized with the CPU, some information must be
exchanged between the CPU and the device to ensure that the data is received reliably.
This interaction between the CPU and an I/O device is usually referred to as ---------------------
-------
a) polling
b) arbitration
c) handshaking
d) interrupting
35. ------------------- approach can place the data directly into the memory or take the data
directly from the memory without direct intervention from the processor.
a) DMA
b) Daisy chain arbitration
c) polling
d) none of these
36. A SCSI device can transfer up to----------- of information per second.

10. a) 40 Mbytes
b) 60 Mbytes
c) 40 Gbytes
d)60 Gbytes
37. ------------------- file system allows sharing in multiple different locations grouped under one folder.
a) Direct
b) distributed
c) sequential
d) parallel
38. Windows 2000 supports -------------- type of file system .
a) NTFS
b) EFS
c) FEFS
d) EFFS
39. The integral subsystem looks after operating system specific functions on behalf of the -------
-----------
a. specific program
b. environment subsystem
c. programmer
d. application
40. Kernel mode drivers exist in ------------------
a. three levels
b. two levels

11. c. four levels
d. single level

12. Part B (Two mark questions)
41. a context is the contents of a ----------- and --------------- at any point of time..
a) MDR, IR
b) CPU registers, PC
c) MDR, PC
d) CPU registers, IR
42 The introduction of mutual exclusion can prevent race conditions but can lead to problems such as -
-------------------
a)deadlock
b) starvation
c) both a and b
d) none of these
43 The controller can access memory in memory cycles which are not used by the particular
bank of memory into which the DMA controller is writing data. This approach, called ----------------
--------
.
a) interrupting
b) cycle stealing
c) swapping
d) paging

13. 44. Windows NT operating system architecture consists of ------------- and ------------------ layers.
a) physical , data link
b) Micro , Macro
c) user mode, Kernel mode
d) Physical , Micro
45. The two sub systems of user mode layer of windows 2000 are ----------- and -----------.
a) excel, executive
b) environment, integral
c) orbit , kernel
d) Kernel , executive
46. The user mode is made up of subsystems which can pass ----------to the appropriate kernel
mode drivers via the ---------
a. I/O requests, I/O manager
b. I/O manager, I/O requests
c. data, proper channel
d. I/O manager, internet
47. The kernel is further separated into a series of ---------and -------------
a. interfaces, device drivers
b. application program, system program
c. application program, interface
d. application program, device drivers
48. The microkernel method, structures the operating system by removing all ----------------from
the kernel and ------------------then as system and user-level programs

14. a. nonessential components, implementing
b. essential components, record
c. essential components, implementing
d. nonessential components, record.
49. User level threads are mostly used on the systems where the operating system does not-----
------------------, but also can be combined with the ---------------------
a. support C++ application, kernel level threads
b. application program, multilevel threads
c. support threads, kernel level threads
d. support local variables, multilevel threads
50. The Worst fit strategy attempts to reduce the problem of ------------by allocating the largest
fragments to -----------------
a. fragmentation, new processes
b. allocation, old process
c. fragmentation, old process
d. allocation, new processes
51. For paging memory management, each process is associated with a--------------. Each entry
in the table contains the ---------------of the corresponding page
a. records, record number
b. lookup table, frame number
c. lookup table, record number
d. page table, frame number

15. 52. CPU bursts vary from process to-----------, and from program to ---------------
a. program, process
b. controller , controller
c. process, program
d. request, CPU.
53. FCFS can yield some very long average----------------, particularly if the first process takes a -
------------
a. wait times, long time
b. throughput time, long time
c. Turnaround time, short time
d. response time, short time.
54. The idea behind the SJF algorithm is to pick the ----------------that needs to be done, get it out
of the way first, and then pick the next ----------------to do next
a. slowest little job, smallest fastest job
b. fastest little job, smallest fastest job
c. first process, last process
d. slowest little job, last job
55. state true/false
Once deadlock has been detected, in order to correct following strategies
Should be
A- Preemption
B- Kill one or more processes
a. A-T, B-T
b. A-F, B-T
c. A-F, B-F

16. d. A-T, B-F
56. If a child dies before its parent----------, the child becomes a -----------
a. calls wait, zombie
b. circular wait, parents
c. preemption, parents
d. circular wait, zombie
57. Concurrency occurs when -------------execution flows are able to run---------------
a. two or more, simultaneously
b. single, separately
c. two or more, one by one
d. single, simultaneously
58. Unix hides the -------------- of tracks, sectors, etc. and presents each file as a ---------- array of
bytes with no internal structure.
a. smoothness, heterogeneous
b. chunkiness, smooth
c. details, name
d. chunkiness, name
59. In disk Index idea is to keep the --------------representation, but take the link fields out of the
blocks and gather them together all in-------------.
a. array, various place
b. array, one place
c. linked-list, one place
d. linked list, various place

17. 60. The I/O handling procedure will require some-------------- from the-----------------
a. status information , I/O device
b. status information, processor
c. resource, processor
d. resource, I/O device
Part C (Four mark questions)
61. match the following
1. Operating system i). application software
2. Library system ii) system software
3. secondary storage iii) smaller capacity
4. Main memory iv) larger capacity
a) 1-ii, 2-i, 3-iv, 4-iii
b) 1-iv,2-ii, 3-I, 4-iii
c) 1-ii,2-i, 3-iii, 4-iv
d) 1-iv, 2-I, 3-ii, 4-iii
62. which of these is a reason for using threads in designing operating systems ?
a) Unlike processes, threads are not independent of one another
b) All threads can access every address in the task .
c) Because threads can share common data, they do not need to use interprocess
communication.
d) Like processes, thread can create children.

18. 63. Arrange the following memories in terms of increasing access time (from low to high)
1. registers
2. Main memory
3 secondary memory
4 cache
a) 1-3 -4 -2
b) 1-4-2-3
c) 3-2-4-1
d) 2-4-1-3
64. Given four processes with Burst time P1=6, P2=8, P3=7 and P4=3 calculate average waiting time
using SJF scheduling algorithm.
a) 7.0 ms
b) 10.25 ms
c) 3.0 ms
d) 17.0 ms
65. match the following
1. pipes i) continuously change their state
2. livelock ii) WNOHANG
3. Killing Zombies iii) fixed size
4. argument iv) web server
a) 1-iv 2-iii 3-I 4- ii
b) 1-iii 2-i 3-iv 4- ii
c) 1-ii 2- I 3-iv 4-iii
d. 1-iii 2-iv 3-ii 4- i
66. Match the following

19. 1. Programmed controlled I/O i. polled I/O
2. Interrupt controlled I/O ii. Cycle stealing
3. DMA iii. maskable and non maskable
a) 1-i , 2-iii, 3-ii
b) 1-ii 2-iii 3-i
c) 1-iii 2-ii 3-i
d) 1-i 2-ii 3-iii
67. Match the following
1. Process manager i. Device detection and installation
2. IPC manager ii. Thread creation
3. PNP manager iii. Drawing windows and menus
4. Window manager iv . Communication between clients.
a) 1- iv , 2-iii, 3- ii 4- i
b) 1-ii, 2-iv , 3- i, 4-iii
c) 1- iii, 2-ii , 3-iv 4- i
d) 1- iv , 2-ii , 3-iii , 4- i
68. State whether the following statement is true/false for Layered Approach
1. In layered approach operating system is broken up into a number of layers (levels).
2. The main advantage of the layered approach is simplicity of construction and debugging.
3. The first layer can’t be debugged without any concern for the rest of the system.
a. 1. True, 2. true, 3. true
b. 1. true, 2. false, 3. true
c. 1. false, 2. false, 3. false

20. d .1. true, 2. true, 3. False
69. match the following
1. The process has finished execution i). Ready State
2. The process being created ii) New State
3. If process uses CPU iii) Terminated
State
a. 1-ii, 2-i, 3-iii
b. 1-iii,2-ii, 3-I,
c. 1-ii,2-i, 3-iii,
d. 1-iii, 2-ii, 3-i,
70. match the following
Set-1
1. The allocator places a process in the smallest block of unallocated memory in which it
will fit.
2. begins at the start of primary memory and allocates memory from the first hole it
encounters large enough to satisfy the request
3. The memory manager places a process in the largest block of unallocated memory
available
Set-2
A. First fit
B. Best fit
C. Worst fit
a. 1-A,2-B,3-C
b. 1-B,2-A,3-C
c. 1-C,2-A,3-B
d. 1-C,2-B,3-A
71. match the following

21. Set-1
1.Time required for a particular process to complete, from submission time to completion
2. Number of processes completed per unit time
3 .The time taken in an interactive program from the issuance of a command to the
commence
Set-2
A. Throughput
B. Turnaround time
C.Response time
a. 1-A,2-B,3-C
b. 1-B,2-A,3-C
c. 1-C,2-A,3-B
d. 1-C,2-B,3-A
72. match the following
Set-1
1. Each process is waiting to obtain a resource which is held by another process
2. processes currently holding resources can request new resources
3. Once a process holds a resource, it cannot be taken away by another process or the
kernel .
A. Hold and Wait
B. No preemption
C. Circular wait
a. 1-A,2-B,3-C

22. b. 1-B,2-A,3-C
c. 1-C,2-A,3-B
d. 1-C,2-B,3-A
73. State whether the following statement is true/false for Mutual Exclusion
1. Mutual exclusion needs to be enforced only when processes access shared modifiable
data
2. Mutual exclusion occurs when a process remains inside its critical section for a finite time
only.
3. Mutual exclusion is a way of making sure that if one process is using a shared modifiable
data, the other processes will be excluded from doing the same thing.
.
a. 1. True, 2. true, 3. true
b. 1. true, 2. false, 3. true
c. 1. false, 2. false, 3. False
d .1. true, 2. true, 3. False
74. match the following
Set-1
1. Read or write the next record or next n bytes of the file.
2. Read or write the record with a given key
3. Read or write the nth record or bytes i through j.
Set-2

23. A. Random Access
B. Sequential Access
C.Indexed Access
a. 1-A,2-B,3-C
b. 1-B,2-C,3-A
c. 1-C,2-A,3-B
d. 1-C,2-B,3-A
75. In IO structure for handshaking which of the following events are
important
1. The device providing the data (the talker) must indicate that valid data
is now available.
2. The device accepting the data (the listener) must indicate that it has
accepted the data.
3. The talker indicates that the data on the bus is no longer valid, and
removes the data from the bus.
a. 1-T,2-T,3-T
b. 1-T,2-F,3-T
c. 1-T,2-T,3-F
d. 1-F,2-T,3-T

24. Answer Keys
Part - A Part - B Part - C
Q. No. Ans. Key Q. No. Ans. Key Q. No. Ans. Key Q. No. Ans. Key
1 A 21 A 41 B 61 A
2 D 22 B 42 C 62 C
3 A 23 C 43 B 63 B
4 B 24 A 44 A 64 A
5 A 25 B 45 B 65 B
6 B 26 A 46 A 66 A
7 B 27 C 47 A 67 B
8 B 28 B 48 A 68 D
9 B 29 A 49 C 69 D
10 B 30 B 50 A 70 B
11 D 31 B 51 D 71 B
12 B 32 A 52 C 72 C
13 B 33 C 53 A 73 A
14 C 34 C 54 B 74 B
15 A 35 A 55 B 75 A
16 B 36 A 56 A
17 A 37 B 57 A
18 B 38 A 58 B
19 C 39 B 59 C
20 B 40 A 60 A