Explore topic-wise MCQs in Computer Science.

A sender uses the Stop-and-Wait ARQ protocol for reliable transmission of frames. Frames are of size 1000 bytes and the transmission rate at the sender is 80 Kbps (1Kbps = 1000 bits/second). Size of an acknowledgement is 100 bytes and the transmission rate at the receiver is 8 Kbps. The one-way propagation delay is 100 milliseconds. Assuming no frame is lost, the sender throughput is __________ bytes/second.

For a host machine that uses the token bucket algorithm for congestion control, the token bucket has a capacity of 1 megabyte and the maximum output rate is 20 megabytes per second. Tokens arrive at a rate to sustain output at a rate of 10 megabytes per second. The token bucket is currently full and the machine needs to send 12 megabytes of data. The minimum time required to transmit the data is _________________ seconds.

Consider the following two phase locking protocol. Suppose a transaction T accesses (for read or write operations), a certain set of objects {O1,...,Ok}. This is done in the following manner: Step 1. T acquires exclusive locks to O1, . . . , Ok in increasing order of their addresses. Step 2. The required operations are performed. Step 3. All locks are released. This protocol will

Which one of the following is TRUE about the above solution?

Consider a computer system with ten physical page frames. The system is provided with an access sequence a1, a2, ..., a20, a1, a2, ..., a20), where each ai number. The difference in the number of page faults between the last-in-first-out page replacement policy and the optimal page replacement policy is __________ [Note that this question was originally Fill-in-the-Blanks question]

Consider a disk queue with requests for I/O to blocks on cylinders 47, 38, 121, 191, 87, 11, 92, 10. The C-LOOK scheduling algorithm is used. The head is initially at cylinder number 63, moving towards larger cylinder numbers on its servicing pass. The cylinders are numbered from 0 to 199. The total head movement (in number of cylinders) incurred while servicing these requests is:   Note : This question was asked as Numerical Answer Type.

Consider a computer system with 40-bit virtual addressing and page size of sixteen kilobytes. If the computer system has a one-level page table per process and each page table entry requires 48 bits, then the size of the per-process page table is _________megabytes.   Note : This question was asked as Numerical Answer Type.

Using the above SDTS, the output printed by a bottom-up parser, for the input aab is

The value of the expression 2 - 5 + 1 - 7 * 3 in this language is __________ ?   Note : This question was asked as Numerical Answer Type.

Let X be a recursive language and Y be a recursively enumerable but not recursive language. Let W and Z be two languages such that Y' reduces to W, and Z reduces to X' (reduction means the standard many-one reduction). Which one of the following statements is TRUE

The maximum possible number of iterations of the while loop in the algorithm is______ [This Question was originally a Fill-in-the-Blanks question]

G = (V, E) is an undirected simple graph in which each edge has a distinct weight, and e is a particular edge of G. Which of the following statements about the minimum spanning trees (MSTs) of G is/are TRUE

I.  If e is the lightest edge of some cycle in G, 
    then every MST of G includes e
II. If e is the heaviest edge of some cycle in G, 
    then every MST of G excludes e

Let G be a complete undirected graph on 4 vertices, having 6 edges with weights being 1, 2, 3, 4, 5, and 6. The maximum possible weight that a minimum weight spanning tree of G can have is. [This Question was originally a Fill-in-the-Blanks question]

The largest possible integer value of x, for which at least one shortest path between some pair of vertices will contain the edge with weight x is ________   Note : This question was asked as Numerical Answer Type

An operator delete(i) for a binary heap data structure is to be designed to delete the item in the i-th node. Assume that the heap is implemented in an array and i refers to the i-th index of the array. If the heap tree has depth d (number of edges on the path from the root to the farthest leaf), then what is the time complexity to re-fix the heap efficiently after the removal of the element?

What will be the output of the following pseudo-code when parameters are passed by reference and dynamic scoping is assumed?

a=3;
void n(x) {x = x * a; print(x);}
void m(y) {a = 1; a = y - a; n(a); print(a);}
void main() {m(a);}

What will be the output of the following C program?

void count(int n)
{
    static int d = 1;
    printf("%d ", n);
    printf("%d ", d);
    d++;
    if(n > 1) count(n-1);
    printf("%d ", d);
}
int main()
{
    count(3);
}

The following function computes the maximum value contained in an integer array p[] of size n (n >= 1)

int max(int *p, int n)
{
    int a=0, b=n-1;
    while (__________)
    {
        if (p[a] <= p[b])
        {
            a = a+1;
        }
        else
        {
            b = b-1;
        }
    }
    return p[a];
}

The missing loop condition is

Consider a carry lookahead adder for adding two n-bit integers, built using gates of fan-in at most two. The time to perform addition using this adder is

The stage delays in a 4-stage pipeline are 800, 500, 400 and 300 picoseconds. The first stage (with delay 800 picoseconds) is replaced with a functionally equivalent design involving two stages with respective delays 600 and 350 picoseconds. The throughput increase of the pipeline is _______ percent. [This Question was originally a Fill-in-the-Blanks question]

The size of the data count register of a DMA controller is 16 bits. The processor needs to transfer a file of 29,154 kilobytes from disk to main memory. The memory is byte addressable. The minimum number of times the DMA controller needs to get the control of the system bus from the processor to transfer the file from the disk to main memory is _________   Note : This question was asked as Numerical Answer Type.

Consider the following experiment.

Step 1. Flip a fair coin twice.
Step 2. If the outcomes are (TAILS, HEADS) then output Y and stop.
Step 3. If the outcomes are either (HEADS, HEAD) or (HEADS, TAILS), 
        then output N and stop.
Step 4. If the outcomes are (TAILS, TAILS), then go to Step 1.

The probability that the output of the experiment is Y is (up to two decimal places). [This Question was originally a Fill-in-the-Blanks question]

Consider the recurrence relation a1 = 8, an = 6n2 + 2n + an-1. Let a99 = k x 104. The value of K is _____   Note : This question was asked as Numerical Answer Type.

The coefficient of x12 in (x3 + x4 + x5 + x6 + ...)3 is. [This Question was originally a Fill-in-the-Blanks question]

Which of the following is/are example(s) of stateful application layer protocols?

(i)  HTTP
(ii) FTP
(iii) TCP
(iv) POP3 

Which one of the following protocols is NOT used to resolve one form of address to another one?

A database of research articles in a journal uses the following schema.

(VOLUME, NUMBER, STARTPGE, ENDPAGE, TITLE, YEAR, PRICE) 

The primary key is (VOLUME, NUMBER, STARTPAGE, ENDPAGE) and the following functional dependencies exist in the schema.

(VOLUME, NUMBER, STARTPAGE, ENDPAGE) -> TITLE
(VOLUME, NUMBER)                     -> YEAR
(VOLUME, NUMBER, STARTPAGE, ENDPAGE) -> PRICE 

The database is redesigned to use the following schemas.

(VOLUME, NUMBER, STARTPAGE, ENDPAGE, TITLE, PRICE)
(VOLUME, NUMBER, YEAR) 

Which is the weakest normal form that the new database satisfies, but the old one does not?

Which one of the following is NOT a part of the ACID properties of database transactions?

Which of the following is NOT a superkey in a relational schema with attributes V, W, X, Y, Z and primary key V Y ?

Consider an arbitrary set of CPU-bound processes with unequal CPU burst lengths submitted at the same time to a computer system. Which one of the following process scheduling algorithms would minimize the average waiting time in the ready queue?

Consider the following code segment.

x = u - t;
y = x * v;
x = y + w;
y = t - z;
y = x * y; 

The minimum number of total variables required to convert the above code segment to static single assignment form is   Note : This question was asked as Numerical Answer Type.

Which of the following languages is generated by the given grammar? S → aS|bS| ε 

Consider the following C program.

#include<stdio.h>
void mystery(int *ptra, int *ptrb) 
{
   int *temp;
   temp = ptrb;
   ptrb = ptra;
   ptra = temp;
}
int main() 
{
    int a=2016, b=0, c=4, d=42;
    mystery(&a, &b);
    if (a < c)
       mystery(&c, &a);
    mystery(&a, &d);
    printf("%dn", a);
}

The output of the program _____________   Note : This question was asked as Numerical Answer Type.

Let G be a weighted connected undirected graph with distinct positive edge weights. If every edge weight is increased by the same value, then which of the following statements is/are TRUE?

P: Minimum spanning tree of G does not change
Q: Shortest path between any pair of vertices does not change

The worst case running times of Insertion sort, Merge sort and Quick sort, respectively, are:

Consider the following C program.

void f(int, short);
void main()
{
  int i = 100;
  short s = 12;
  short *p = &s;
  __________ ;   // call to f()
}

Which one of the following expressions, when placed in the blank above, will NOT result in a type checking error?

The number of different topological orderings of the vertices of the graph is   Note : This question was asked as Numerical Answer Type.

A queue is implemented using an array such that ENQUEUE and DEQUEUE operations are performed efficiently. Which one of the following statements is CORRECT (n refers to the number of items in the queue)?

A processor can support a maximum memory of 4 GB, where the memory is word-addressable (a word consists of two bytes). The size of the address bus of the processor is at ____ least bits.   Note : This question was asked as Numerical Answer Type.

We want to design a synchronous counter that counts the sequence 0-1-0-2-0-3 and then repeats. The minimum number of J-K flip-flops required to implement this counter is   Note : This question was asked as Numerical Answer Type.

The 16-bit 2’s complement representation of an integer is 1111 1111 1111 0101; its decimal representation is   Note : This question was asked as Numerical Answer Type.

Consider the Boolean operator # with the following properties: x#0 = x, x#1 = x', x#x = 0 and x#x' = 1 Then x#y is equivalent to

Two eigenvalues of a 3 x 3 real matrix P are (2 + √ -1) and 3. The determinant of P is _____   Note : This question was asked as Numerical Answer Type.

A probability density function on the interval [a, 1] is given by 1 / x2 and outside this interval the value of the function is zero. The value of a is :   Note : This question was asked as Numerical Answer Type.

In a process, the number of cycles to failure decreases exponentially with an increase in load. At a load of 80 units, it takes 100 cycles for failure. When the load is halved, it takes 10000 cycles for failure. The load for which the failure will happen in 5000 cycles is ________.

If f(x) = 2x7 + 3x - 5 Which of the following is a factor of f(x)?

Consider the following statements relating to the level of poker play of four players P, Q, R, and S.

I    P always beats Q
II.  R always beats S
III. S loses to P only sometimes
IV.  R always loses to Q 

Which of the following can be logically inferred from the above statements?

(i) P is likely to beat all the three other players
(ii) S is the absolute worst player in the set 

Indian currency notes show the denomination indicated in at least seventeen languages. If this is not an indication of the nation’s diversity, nothing else is. Which of the following can be logically inferred from the above sentences?

Which product contributes the greatest fraction to the revenue of the company in that year?

A cube is built using 64 cubic blocks of side one unit. After it is built, one cubic block is removed from every corner of the cube. The resulting surface area of the body (in square units) after the removal is __________.