# UGC NET Computer Science Previous Questions June 2013 Paper 2 - Part 5

41.       How many different Boolean functions of degree 4 are there?
(A) 24      (B) 28
(C) 212    (D) 216
Explanation:
Number of Boolean expression = 2^2n
= 2^24 = 216
42.       A Boolean operator Ө  is defined as follows:
1Ө1=1, 1Ө0=0, 0Ө1=0 and 0Ө0=1
What will be the truth value of the expression (xӨy)Өz = xӨ(yӨz)?
(A) Always false
(B) Always true
(C) Sometimes true
(D) True when x, y, z are all true
43.       Which one of the following is decimal value of a signed binary number 1101010, if it is in  2's complement form?
(A) -42                (B) - 22
(C) -21               (D) -106
44.       A set of processors P1, P2, ......, Pk can execute in parallel if Bernstein's conditions are satisfied on a pair wise basis; that is
P1 || P2 || P3 || ..... || Pk if and only if:
(A) Pi || Pj for all i ≠ j
(B) Pi || Pj for all i = j+1
(C) Pi || Pj for all i ≤ j
(D) Pi || Pj for all i ≥ j
Explanation:
Bernstein’s Condition:
1. If process Pi writes to a memory cell Mi, then no process Pj can read the cell Mi.
2. If process Pi read from a memory cell Mi, then no process Pj can write to the cell Mi.
3. If process Pi writes to a memory cell Mi, then no process Pj can write to the cell Mi.
45.       When a mobile telephone physically moves from one to another cell, the base station transfers ownership to the cell getting strongest signal. This process is known as.................
(A) handoff                   (B) mobile switching
(C) mobile routing       (D) cell switching

46.       A virtual memory based memory management algorithm partially swaps out a process. This is an example of
(A) short term scheduling                  (B) long term scheduling
(C) medium term scheduling             (D) mutual exclusion
47.       Assuming that the disk head is located initially at 32, find the number of disk moves required with FCFS if the disk queue of I/O block requests are 98, 37, 14, 124, 65, 67:
(A) 310               (B) 324
(C) 320              (D) 321
48.       Let the page fault service time be 10 millisecond(ms) in a computer with average memory access time being 20 nanosecond(ns). If one page fault is generated for every 106 memory accesses, what is the effective access time for memory?
(A) 21 ns           (B) 23 ns
(C) 30 ns           (D) 35 ns
49.       Consider the following UNIX command:
sort <in> temp; head -30 <temp; rm temp
Which of the following functions shall be performed by this command?
(A) Sort, taking the input from "temp", prints 30 lines from temp and delete the file temp
(B) Sort the file "temp", removes 30 lines from temp and delete the file temp
(C) Sort, taking the input from "in" and writing the output to "temp" then prints 30 lines from temp on terminal. Finally "temp" is removed.
(D) Sort, taking the input from 'temp" and then prints 30 lines from "temp" on terminal. Finally "temp" is removed.