FINALTERM EXAMINATION
Spring 2010
CS604- Operating Systems (Session - 4)
Time: 90 min
M a r k s: 60
Question No: 1 ( M a r k s: 1 ) http://vuzs.net
A ---------------- (or an exception)
is a software-generated interrupt caused either by an error (division
by zero or invalid memory access) or by a user request for an operating
system service.
► Interrupt
► Trap
► Signal
► Process
Question No: 2 ( M a r k s: 1 ) http://vuzs.net
Which register holds the smallest legal physical memory address for a process?
► Base register
► Limit register
► Status register
► None of the given options
Question No: 3 ( M a r k s: 1 ) http://vuzs.net
The process of switching from one process to another is called -----------------
► context switching
► scheduling
► quantum period
► latency
Question No: 4 ( M a r k s: 1 ) http://vuzs.net
The --------------semaphore provides mutual exclusion for accesses to the buffer pool and is initialized to the value 1.
► mutex
► binary
► couting
► none of the given options
Question No: 5 ( M a r k s: 1 ) http://vuzs.net
Binary semaphores are those that have only two values---------
► 0 and n
► 0 and 0
► 0 and 1
► None of the given options
Question No: 6 ( M a r k s: 1 ) http://vuzs.net
Addresses generated relative to part of program, not to start of physical memory are
► Virtual
► Physical
► Relocatable
► Symbolic
Question No: 7 ( M a r k s: 1 ) http://vuzs.net
Object files and libraries are combined by a ------------- program to produce the executable binary
► Compiler
► Linker
► Text editor
► Loader
Question No: 8 ( M a r k s: 1 ) http://vuzs.net
Physical
memory is broken down into fixed-sized blocks, called----------- and
Logical memory is divided into blocks of the same size, called
-----------
► Frames, pages
► Pages, Frames
► Frames, holes
► Holes, segments
Question No: 9 ( M a r k s: 1 ) http://vuzs.net
A page table needed for keeping track of pages of the page table is called --------------
► 2-level paging
► Page directory
► Page size
► Page table size
Question No: 10 ( M a r k s: 1 ) http://vuzs.net
The address generated by the CPU, after any indexing or other addressing-mode arithmetic, is called a --------address, and the address it gets translated to by the MMU is called a ---------address.
► Virtual, physical
► Hexadecimal, Binary,
► Valid, invalid
► Physical, Virtual
Question No: 11 ( M a r k s: 1 ) http://vuzs.net
Each page is a power of -------- bytes long in paging scheme.
► 2
► 3
► 4
► 5
Question No: 12 ( M a r k s: 1 ) http://vuzs.net
_______
is a way to establish a connection between the file to be shared and
the directory entries of the users who want to have aces to this file.
► Link
► Directory
► Common Group
► Access Permission
Question No: 13 ( M a r k s: 1 ) http://vuzs.net
When a _____link is created, a directory entry for the existing file is created
► Soft
None of the given options
► Hard
► Soft or Hard
► Soft or Hard
Question No: 14 ( M a r k s: 1 ) http://vuzs.net
The ___________ method requires each file to occupy a set of contiguous blocks on the disk.
► Contiguous Allocation
► Linked Allocation
► Indexed Allocation
► None of the given options
Question No: 15 ( M a r k s: 1 ) http://vuzs.net
Which part of the computer system helps in managing the file and memory management system?
► Operating System
► Device Drivers
► Application Software
► Hardware
Question No: 16 ( M a r k s: 1 ) http://vuzs.net
Which of the following is correct definition for wait operation?
► wait(S) {
while(S<=0)
;// no op
S--;
}
► wait(S) {
S++;
}
► wait(S) {
while(S>=0)
;// no op
S--;
}
► wait(S) {
S--;
}
Question No: 17 ( M a r k s: 1 ) http://vuzs.net
Wrong use of wait and signal operations (in context with semaphores) can cause _________ problem(s).
► Mutual Exclusion
► Deadlock
► Bounded Waiting
► All of the given options are correct
Question No: 18 ( M a r k s: 1 ) http://vuzs.net
If a system is not in a safe state, there can be no deadlocks.
► True
► False
Question No: 19 ( M a r k s: 1 ) http://vuzs.net
If
a process continues to fault, replacing pages, for which it then faults
and brings back in right away. This high paging activity is called
___________.
► paging
► thrashing
► page fault
► CPU utilization
Question No: 20 ( M a r k s: 1 ) http://vuzs.net
In _____________ page replace algorithm we will replace the page that has not been used for the longest period of time.
► counter based
► Least Frequently Used
► FIFO
► LRU
Question No: 21 ( M a r k s: 1 ) http://vuzs.net
Overlays are implemented by the _________________
► Operating system
► Programmer
► Kernel
► Shell
Question No: 22 ( M a r k s: 1 ) http://vuzs.net
An acyclic graph does not allow directories to have shared subdirectories and files.
► True
► False
Question No: 23 ( M a r k s: 1 ) http://vuzs.net
The size of pages and frames are same in logical memory and physical memory respectively.
► True
► False
Question No: 24 ( M a r k s: 1 ) http://vuzs.net
A
modification of free-list approach in free space managment is to store
the addresses of n free blocks in the first free block. Known as ______.
► counting
► linked list
► bit vector
► grouping
Question No: 25 ( M a r k s: 1 ) http://vuzs.net
In
deadlock detection and recovery algorithm, a deadlock exists in the
system if and only if the wait for graph contains a _____________
► Cycle
► Graph
► Edge
► Node
Question No: 26 ( M a r k s: 1 ) http://vuzs.net
Intel is basically designed for following Operating Systems except __________.
► MULTICS
► OS/2
► Windows
► Linux
Question No: 27 ( M a r k s: 1 ) http://vuzs.net
Following is NOT true about Virtual memory.
► Virtual memory help in executing bigger programs even greater in size that of main memory.
►
Virtual memory makes the processes to stuck when the collective size of
all the processes becomes greater than the size of main memory.
► Virtual memory also allows files and memory to be shared by several different processes through page sharing.
► Virtual memory makes the task of programming easier because the programmer need not worry about the amount of physical memory,
Question No: 28 ( M a r k s: 1 ) http://vuzs.net
The execution of critical sections must NOT be mutually exclusive
► True
► False
Question No: 29 ( M a r k s: 1 ) http://vuzs.net
The critical section problem can be solved by the following except
► Software based solution
► Firmware based solution
► Operating system based solution
► Hardware based solution
Question No: 30 ( M a r k s: 1 ) http://vuzs.net
The bottom layer in the layered approach of Operating System is-----------
► User interface
► Hardware
► Kernel
► None of the given options
Question No: 31 ( M a r k s: 2 )
Under what conditions can you use the Wait-for graph to detect deadlock?
ANS:
We
use wait-for graph in a condition if all the resources have only a
single instance, then we use deadlock detection algorithm that uses a
variant of the resource allocation graph.
Question No: 32 ( M a r k s: 2 )
List the four events that cause the execution of a piece of code in kernel.
Ans:
List the four events that cause the execution of a piece of code in kernel:
1- Interrupt
2- Trap
3- System call
4- signal
Question No: 33 ( M a r k s: 2 )
What is basic logic in FIFO page replacement algorithm?
Ans:
A
FIFO page replacement algorithm correlates with every page to know the
time when that page was brought into memory. When a page becomes to be
replaced, the oldest page is chosen. It is not necessary to record the
time when the page was brought in. for this we can create a FIFO queue
to hold all pages into memory. We simply replace the page at the head of
the queue.
Question No: 34 ( M a r k s: 2 )
The problem with using an acyclic-graph structure is ensuring that there are no cycles. What is the solution?
Question No: 35 ( M a r k s: 3 )
What are the three different stages/times when the addresses can be bound to instructions and data?
Ans:
1- compile time
2- load time
3- execution time
Question No: 36 ( M a r k s: 3 )
What is Mounting? Name two types of mounting. Give your answer with respect to File System?
Question No: 37 ( M a r k s: 3 )
List down two major benefits of Virtual Memory
Ans:
1-Users would be able to write programs for an extremely lagre virtual address space which simplify the programming task.
2- less input and output needed to load or swap each user program into memory, so each user program would run faster.
Question No: 38 ( M a r k s: 3 )
Write three main responsibilities of an operating system?
Ans:
1- manage secondary storage devices
2- manage processes
3- allow a user to manage files and directories properly
Question No: 39 ( M a r k s: 5 )
Briefly
explain the difference Least frequently used and Most Frequently Used
algorithms with respect to Page Replacement techniques.
Ans:
Question No: 40 ( M a r k s: 5 )
Calculate
the maximum no. of bits required for page number and no. of bits
required for frames when there are 16 pages and 32 frames in the system?
