Friday, 7 October 2016

UGC NET Computer Science Paper II June 2013 (Re-test 8th Sept. 2013) - Part 5

41.       Cross_tab displays permit users to view ................ of multidimensional data at a time.
(A) One dimension                  (B) Two dimensions
(C) Three dimensions             (D) Multidimensions
Answer: B
42.       A method to provide secure transmission of email is called .................
(A) TLS              (B) SA
(C) IPSec          (D) PGP
Answer: D
43.       Thoma’s-write rule is .................
(A) Two phase locking protocol        (B) Timestamp ordering protocol
(C) One phase locking protocol        (D) Sliding window protocol
Answer: B
44.       Match the following:
List – I                                                   List - II
Process state transition                   Reason for transition
a. Ready→Running                           i. Request made by the process
is satisfied or an event for which
it was waiting occurs.
b. Blocked→Ready                             ii. Process wishes to wait for
some action by another process.
c. Running→Blocked                         iii. The process is dispatched.
d Running→Ready                            iv. The process is preempted.
Codes :
      a   b   c    d
(A) iii   i    ii    iv
(B) iv   i    iii   ii
(C) iv  iii   i     ii
(D) iii  iii   ii     i
Answer: A
45.       The hit ratio of a Translation Look Aside Buffer (TLAB) is 80%. It takes 20 nanoseconds (ns) to search TLAB and 100 ns to access main memory. The effective memory access time is ................
(A) 36 ns           (B) 140 ns
(C) 122 ns         (D) 40 ns
Answer: B
Explanation:
Hit ratio is the percentage of time that a frame number is
found in the TLB
– Associative lookup time is a time units
– Memory cycle time is m time units
– Hit ratio is r
– Effective Access Time (EAT) = (m + a) r + (2m + a)(1 – r)
Example
If a = 20 ns, m = 100 ns, and r = 80%, then
EAT = (100 + 20) 0.8 + (2(100) + 20)(1 - 0.8) = 140 ns
For r = 98%, then EAT = 122 ns

46.       Consider the input/output (I/O) requests made at different instants of time directed at a hypothetical disk having 200 tracks as given in the following table:
Assume that:
Current head position is at track no. 65
Direction of last movement is towards higher numbered tracks
Current clock time is 160 milliseconds
Head movement time per track is 1 millisecond.
“look” is a variant of “SCAN” disk-arm scheduling algorithm. In this algorithm, if no more I/O requests are left in current direction, the disk head reverses its direction. The seek times in Shortest Seek First (SSF) and “look” disk-arm scheduling algorithms respectively are:
(A) 144 and 123 milliseconds                       (B) 143 and 123 milliseconds
(C) 149 and 124 milliseconds           (D) 256 and 186 milliseconds
Answer: B
47.       Assume that an implementation of Unix operating system uses i-nodes to keep track of data blocks allocated to a file. It supports 12 direct block addresses, one indirect block address and one double indirect block address. The file system has 256 bytes block size and 2 bytes for disk block address. The maximum possible size of a file in this system is
(A) 16 MB          (B) 16 KB
(C) 70 KB          (D) 71 KB
Answer: Marks given to all
48.       Which of the following set of Unix commands will always display “WELCOME” ?
(A) export title=WELCOME; Echo $title
(B) title = WELCOME; export $ title ; sh –c “echo $title”
(C) title = WELCOME; export title ; sh –c “echo $title”
(D) title = WELCOME; echo $title
Answer: C
49.       What type of logic circuit is represented by the figure shown below?
(A) XOR             (B) XNOR
(C) XAND          (D) XNAND
Answer: B
50.    The speed up of a pipeline processing over an equivalent non-pipeline processing is defined by the ratio:
Where n → no. of tasks
tn → time of completion of each task
k → no. of segments of pipeline
tp → clock cycle time
S → speed up ratio
Answer: A

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