Andhra University 2006 B.E Information Technology COMPUTER SCIENCE
Wednesday, 01 May 2013 08:05Web
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x.f (1); ((P) y).f(1); z.f(1);
Here ( (P) y) denotes a typecast of y to P. The output produced by executing the above program fragment will be
1 two one
2 one 1
2 one two
2 two 2
76. Which of the subsequent is NOT an advantage of using shared, dynamically linked libraries as opposed to using statically linked libraries?
(a) Smaller sizes of executable files
(b) Lesser overall page fault rate in the system
(c) Faster program startup
(d) Existing programs need not be re-linked to take advantage of newer versions of libraries
77. A uni-processor computer system only has 2 processes, both of which alternate 10ms CPU bursts with 90ms I/O bursts. Both the processes were created at nearly the identical time. The I/O of both processes can proceed in parallel. Which of the subsequent scheduling strategies will outcome in the lowest CPU utilization (over a long period of time) for this system?
First come 1st served scheduling
Shortest remaining time 1st scheduling
Static priority scheduling with various priorities for the 2 processes
Round robin scheduling with a time quantum of five ms.
A processor uses 2-level page tables for virtual to physical address translation. Page tables for both levels are stored in the main memory. Virtual and physical addresses are both 32 bits wide. The memory is byte addressable. For virtual to physical address translation, the 10 most significant bits of the virtual address are used as index into the 1st level page table while the next 10 bits are used as index into the 2nd level page table. The 12 lowest significant bits of the virtual address are used as offset within the page. presume that the page table entries in both levels of page tables are four bytes wide. Further, the processor has a translation look-aside buffer (TLB), with a hit rate of 96%. The TLB caches recently used virtual page numbers and the corresponding physical page numbers. The processor also has a physically addressed cache with a hit rate of 90%. Main memory access time is 10 ns, cache access time is one ns, and TLB access time is also one ns.
78. Assuming that no page faults occur, the avg. time taken to access a virtual address is approximately (to the closest 0.5 ns)
1.5 ns
2 ns
3 ns
4 ns
79. Suppose a process has only the subsequent pages in its virtual address space: 2 contiguous code pages starting at virtual address 0x00000000, 2 contiguous data pages starting at virtual address OxO0400000, and a stack page starting at virtual address 0xFFFFF000. The amount of memory needed for storing the page tables of this process is
8 KB
12 KB
16 KB
20 KB
THE subsequent info TO Q. 80-81
Suppose we want to synchronize 2 concurrent processes P and Q using binary semaphores S and T. The code for the processes P and Q is shown beneath.
Process P: Process Q:
while (1) { while (1) {
W: Y:
print '0’; print '1'
print '0'; print '1'
X: z:
} }
Synchronization statements can be inserted only at points W, X, Y and Z
80. Which of the subsequent will always lead to an output staring with '001100110011' ?
P(S) at W, V(S) at X, P(T) at Y, V(T) at Z, S and T initially one
P(S) at W, V(T) at X, P(T) at Y, V(S) at Z, S initially I, and T initially 0
p(S) at W, V(T) at X, p(T) at Y, V(S) at Z, S and T initially one
P(S) at W, V(S) at X, p(T) at Y, V(T) at Z, S initially 1, and T initially 0
81. Which of the subsequent will ensure that the output string never contains a substring of the form 0.1"0 or 10"1 where n is odd?
p(S) at W, V(S) at X, p(T) at Y, V(T) at Z, S and T initially one
P(S) at W, V(T) at X, p(T) at Y, V(S) at Z, Sand T initially one
P(S) at W, V(S) at X, P(S) at Y, V(S) at Z, S initially one
V(S) at W, V(T) at X, P(S) at Y, P(T) at Z,S and T initially one
82. The subnet mask for a particular network is 255.255.31.0. Which of the subsequent pairs of IP addresses could belong to this network?
(a) 172.57.88.62 and 172.56.87.233
(b) 10.35.28.2 and 10.35.29.4
(c) 191.203.31.87 and 191.234.31.88
(d) 128.8.129.43 and 128.8.161.55
83. A 2km long broadcast LAN has 10 seven bps bandwidth and uses CSMA/CD. The signal travels along the wire at two x 10 eight m/s. What is the minimum packet size that can be used on this network?
50 bytes
100 bytes
200 bytes
None of the above
84. Host A is sending data to host B over a full duplex link. A and B are using the sliding window protocol for flow control. The send and receive window sizes are five packets every. Data packets (sent only from A to B) are all 1000 bytes long and the transmission time for such a packet is 50 m s. Acknowledgement packets (sent only from B to A) are very small and require negligible transmission time. The propagation delay over the link is 200 m S. What is the maximum achievable throughput in this communication?
(a) 7.69 x 10 six bps (b) 11.11 x 10 six bps
(c) 12.33 x 10 six bps (d) 15.00 x 10 six bps
85. Consider the subsequent functional dependencies in a database:
Date _ of _ Birth ® Age Age ® Eligibility
Name ® Roll _number Roll _number ® Name
Course _number ® Course _name Course _ number ® Instructor
(Roll_ number, Course _number) ® Grade
The relation (Roll _ number, Name, Date_of_birth, Age) is
(a) in 2nd normal form but not in 3rd normal form
(b) in 3rd normal form but not in BCNF
(c) in BCNF
(d) in none of the above
86. Consider the set of relations shown beneath and the SQL query that follows:
Students: (Roll _ number, Name, Date _ of _birth)
Courses: (Course _ number, Course _name, Instructor)
Grades: (Roll _ number, Course _ number, Grade)
choose distinct Name
from Students, Courses, Grades
where Students. Roll _number = Grades. Roll _number
and Courses. Instructor = Korth
and Courses. Course _number = Grades. Course _number
and Grades. grade = A
Which of the subsequent sets is calculated by the above query ?
(a) Names of students who have got an A grade in all courses taught by Korth
(b) Names of students who have got an A grade in all courses
(c) Name of students who have got an A grade in at lowest 1 of the courses taught by
Korth
(d) None of the above
87. Consider 3 data items D1, D2, and D3, and the subsequent execution schedule
of transactions T1, T2, and T3. In the diagram, R(D) and W(D) denote the actions
studying and writing the data item D respectively.
T1 T2 T3
R (D3);
R (D2);
W (D2);
R (D2);
R (D3);
Time R(D1);
W(Dl);
W(D2);
W(D3);
R(Dl);
R(D2);
W(D2);
W(Dl);
The schedule is serializable as T2; T3; T1
The schedule is serializable as T2; T1; T3
The schedule is serializable as T3; T2; T1
The schedule is not serializable
88. In the subsequent C program fragment, j, k n and TwoLog_n are integer variables, and A is an array of integers. The variable n is intialized to an integer ³ 3, and TwoLog _n is initialized to the value of2* é iog 2(n) ù
for (k = 3; k < = n; k++)
A [k} = 0;
for (k=2; k <= TwoLog_n; k++)
for (j=k + 1; j <= n; j++)
A [j] = A (j] || (j%k);
for (j=3; j <= n; j++)
if (!A[j]) print f ("%d ",j);
The set of numbers printed by this program fragment is
(a) {m | m £ n, ( $ i) [m = i!]} (b) {m | m £ n, ( $ i) [m = i 2]}
(c) {m I m £ n, m is prime} (d) {}
89. Consider the C program shown beneath.
# include
#define print (x) print f ("%d", x)
intx;
void Q (int z) {
z + = x; print (z);
}
void p (int *y) {
int x = *y+2;
Q (x); *y = x-1;
print (x)
}
main (void) {
x=5;
p (&x);
print (x);
}
The output of this program is
1276
22 12 11
14 six 6
766
90. Consider the function f described beneath.
struct item {
int data;
struct item * next;
};
int, f(struct item *p) {
return ((p = = NULL) | | (p - > next = = NULL) ||
(( P-> data < = p - > next - > data) &&
f (p - > next)));
}
For a provided linked list p, the function f returns one if and only if
the list is empty or has exactly 1 element
the elements in the list are sorted in non-decreasing order of data value
the elements in the list are sorted in non-increasing order of data value
not all elements in the list have the identical data value.
| Earning: Approval pending. |
