ISRO Scientist/Engineer CS Solved Papers

Consider the following sequence of micro-operations. (MBR = Memory Base Register, PC = Program Counter, MAR = Memory Address Register.)
$$\begin{aligned} \text{MBR} &\leftarrow \text{PC} \\ \text{MAR} &\leftarrow X \\ \text{PC} &\leftarrow Y \\ \text{Memory} &\leftarrow \text{MBR} \end{aligned}$$
Which one of the following is a possible operation performed by this sequence?

Instructions execution in a processor is divided into 5 stages: Instruction Fetch (IF), Instruction Decode (ID), Operand Fetch (OF), Execute (EX), and Write Back (WB). These stages take 5, 4, 20, 10 and 3 nanoseconds (ns) respectively. A pipelined implementation of the processor requires buffering between each pair of consecutive stages with a delay of 2 ns. The execution time for 20 instructions on this pipeline is:

A processor can support a maximum memory of 8 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.

Which of the following addressing mode is best suited to access elements of an array of contiguous memory locations?

Consider the schema $R(S, T, U, V)$ and the dependencies $S \rightarrow T,\; T \rightarrow U,\; U \rightarrow V,\; V \rightarrow S$. Let $R = \{R_1, R_2\}$ such that $R_1 \cap R_2 = \Phi$. Then the decomposition is:

A FAT (file allocation table) based file system is being used and the total overhead of each entry in the FAT is 4 bytes in size. Given a $100 \times 10^6$ bytes' disk on which the file system is stored and data block size is $10^3$ bytes, the maximum size of a file that can be stored on this disk in units of $10^6$ bytes is

Which of the following is are drawbacks of the Two-Phase Locking (2-PL) mechanism?
I. Deadlock
II. Serializability
III. Starvation
IV. Cascading Rollback

The given table has two attributes $A$ and $C$ where $A$ is the primary key and $C$ is the foreign key referencing $A$ with on-delete cascade.

Consider the relation scheme $R = \{E, F, G, H, I, J, K, L, M, N\}$ and the set of functional dependencies:
$$\{\{E, F\} \rightarrow \{G\},\; \{F\} \rightarrow \{I, J\},\; \{E, K\} \rightarrow \{H, L, M\},\; \{L\} \rightarrow \{N\}\}$$
on $R$. What is the Key for $R$?

Which of the following is/are TRUE?
I. No relation can be in both BCNF and 3NF
II. Every relation in BCNF is also in 3NF
III. A relation $R$ is in 3NF if every non-prime attribute of $R$ is fully functionally dependent on every key of $R$.
IV. Every relation in 3NF is also in BCNF

The hamming distance between the octets of $0\text{x}0\text{A}$ and $0\text{x}05$ is

In a class B network on the internet, the subnet mask is 255.255.240.0. What is the maximum number of hosts per subnet?

A Pure ALOHA network transmits 200-bit frames on a shared channel of 200 kbps. What is the throughput if the system (all stations together) produces 1000 frames per second?

Count to infinity is a problem associated with

ARP request and reply packets are

Consider the following C language program

#include <stdio.h>
#define print(x) printf("%d", x)
int x;
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);
}

Consider the following C program:

#include <stdio.h>
void first() {
    printf("Hello World");
}
void main() {
    void *ptr() = first;
    ptr++;
    ptr();
}

What does the following C-statement declare?

int (*f) (int *);

Given any two functions $f(\cdot)$ and $g(\cdot)$, which of the following is TRUE about $h(n) = f(n) + g(n)$?
I. $h(n)$ is $\Theta(\max\{f(n), g(n)\})$.
II. $h(n)$ is $\Omega(\max\{f(n), g(n)\})$.
III. $h(n)$ is $O(\max\{f(n), g(n)\})$.

Let $A_1, A_2, A_3$, and $A_4$ be four matrices of dimensions $10 \times 5$, $5 \times 20$, $20 \times 10$, and $10 \times 5$, respectively. The minimum number of scalar multiplications required to find the product $A_1 \times A_2 \times A_3 \times A_4$ using the basic matrix multiplication method is

Which one of the following inequalities hold asymptotically true?

Consider a complete binary tree with 7 nodes. Let $A$ denote the set of first 3 elements obtained by performing Breadth-First Search (BFS) starting from the root. Let $B$ denote the set of first 3 elements obtained by performing Depth-First Search (DFS) starting from the root. The value of $|A - B|$ is

Which of these data structures can be used for efficiently storing the symbol table in a compiler implementation?

A company needs to develop digital signal processing software for one of its newest inventions. The software is expected to have 40000 lines of code. The company needs to determine the effort in person-months needed to develop this software using the basic COCOMO model. The multiplicative factor for this model is given as 2.8 for the software development on embedded systems, while the exponentiation factor is given as 1.20. What is the estimated effort in Person-Months?

How many onto (or surjective) functions are there from an $n$-element ($n \ge 2$) set to a 2-element set?