# Recent questions tagged gate2017-1

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Errors violating the condition ‘any variable must be declared before its use’ are detected during semantic analysis. Why cannot it come under syntax analysis? Does declaration not fall under Syntax?
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Consider a $2-$way set associative cache with $256$ blocks and uses $LRU$ replacement. Initially the cache is empty. Conflict misses are those misses which occur due to the contention of multiple blocks for the same cache set. Compulsory misses occur due to first time access ... $10$ times. The number of conflict misses experienced by the cache is _________ .
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The values of parameters for the Stop-and-Wait ARQ protocol are as given below: Bit rate of the transmission channel = $1$ Mbps. Propagation delay from sender to receiver = $0.75$ ms. Time to process a frame = $0.25$ ms. Number of bytes in ... efficiency (expressed in percentage) of the Stop-and-Wait ARQ protocol for the above parameters is _____________ (correct to $2$ decimal places).
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A multithreaded program $P$ executes with $x$ number of threads and uses $y$ number of locks for ensuring mutual exclusion while operating on shared memory locations. All locks in the program are non-reentrant, i.e., if a thread holds a lock $l$, then it cannot re-acquire lock $l$ without releasing it. If a thread is ... deadlock are: $x = 1, y = 2$ $x = 2, y = 1$ $x = 2, y = 2$ $x = 1, y = 1$
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Consider the C functions foo and bar given below: int foo(int val) { int x=0; while(val > 0) { x = x + foo(val--); } return val; } int bar(int val) { int x = 0; while(val > 0) { x= x + bar(val-1); } ... $6$ and $6$ respectively. Infinite loop and abnormal termination respectively. Abnormal termination and infinite loop respectively. Both terminating abnormally.
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Consider the C code fragment given below. typedef struct node { int data; node* next; } node; void join(node* m, node* n) { node* p = n; while(p->next != NULL) { p = p->next; } p->next = m; } Assuming that m and n point to valid NULL-terminated linked ... or append list m to the end of list n. cause a null pointer dereference for all inputs. append list n to the end of list m for all inputs.
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Consider the following C program. #include<stdio.h> #include<string.h> void printlength(char *s, char *t) { unsigned int c=0; int len = ((strlen(s) - strlen(t)) > c) ? strlen(s) : strlen(t); printf("%d\n", len); } void main() { char *x = "abc"; ... that $strlen$ is defined in $string.h$ as returning a value of type $size\_t$, which is an unsigned int. The output of the program is __________ .
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In a RSA cryptosystem, a participant $A$ uses two prime numbers $p = 13$ and $q = 17$ to generate her public and private keys. If the public key of $A$ is $35$, then the private key of $A$ is __________ .
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In a database system, unique timestamps are assigned to each transaction using Lamport's logical clock. Let $TS(T_{1})$ and $TS(T_{2})$ be the timestamps of transactions $T_{1}$ and $T_{2}$ respectively. Besides, $T_{1}$ holds a lock on the ... , but not starvation-free. The database system is starvation-free, but not deadlock-free. The database system is neither deadlock-free nor starvation-free.
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A cache memory unit with capacity of $N$ words and block size of $B$ words is to be designed. If it is designed as a direct mapped cache, the length of the TAG field is 10 bits. If the cache unit is now designed as a 16-way set-associative cache, the length of the TAG field is ____________ bits.
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Consider a two-level cache hierarchy with $L1$ and $L2$ caches. An application incurs $1.4$ memory accesses per instruction on average. For this application, the miss rate of $L1$ cache is $0.1$; the $L2$ cache experiences, on average, $7$ misses per $1000$ instructions. The miss rate of $L2$ expressed correct to two decimal places is ________.
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0 answers 16 views
Consider the expression $(a-1) * (((b+c)/3)+d)$. Let $X$ be the minimum number of registers required by an optimal code generation (without any register spill) algorithm for a load/store architecture, in which only load and store instructions can have memory operands and arithmetic instructions can have only register or immediate operands. The value of $X$ is _____________ .
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Consider the following C code: #include<stdio.h> int *assignval (int *x, int val) { *x = val; return x; } void main () { int *x = malloc(sizeof(int)); if (NULL == x) return; x = assignval (x,0); if (x) { x = (int *)malloc( ... be made as $x == NULL$ and not as shown. compiles successfully but execution may result in dangling pointer. compiles successfully but execution may result in memory leak.
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The output of executing the following C program is _______________ . #include<stdio.h> int total(int v) { static int count = 0; while(v) { count += v&1; v >>= 1; } return count; } void main() { static int x=0; int i=5; for(; i>0; i--) { x = x + total(i); } printf("%d\n", x); }
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Let $A$ be $n\times n$ real valued square symmetric matrix of rank 2 with $\sum_{i=1}^{n}\sum_{j=1}^{n}A^{2}_{ij} =$ 50. Consider the following statements. One eigenvalue must be in $\left [ -5,5 \right ]$ The eigenvalue with the largest ... strictly greater than 5 Which of the above statements about eigenvalues of $A$ is/are necessarily CORRECT? Both I and II I only II only Neither I nor II
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Consider the following grammar: stmt $\rightarrow$ if expr then expr else expr; stmt | $0$ expr $\rightarrow$ term relop term | term term $\rightarrow$ id | number id $\rightarrow$ a | b | c number $\rightarrow [0-9]$ where relop is a relational operator (e.g.. $<$ ... example. the program if $e_1$ then $e_2$ else $e_3$ has $2$ control flow paths. $e_1 \rightarrow e_2$ and $e_1 \rightarrow e_3$.
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Let $A$ and $B$ be finite alphabets and let $\#$ be a symbol outside both $A$ and $B$. Let $f$ be a total function from $A^{*}$ to $B^{*}$. We say $f$ is computable if there exists a Turing machine $M$ which given an input $x \in A^{*}$ ... . If $f$ is computable then $L_{f}$ is recursive, but not conversely. If $f$ is computable then $L_{f}$ is recursively enumerable, but not conversely.
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Consider a database that has the relation schemas EMP(EmpId, EmpName, DeptId), and DEPT(DeptName, DeptId). Note that the DeptId can be permitted to be NULL in the relation EMP. Consider the following queries on the database expressed in tuple relational calculus. {$t$ | $\exists$u $\in$ ... v[DeptId]))} Which of the above queries are safe? I and II only I and III only II and III only I, II and III
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Let $X$ be a Gaussian random variable with mean 0 and variance $\sigma ^{2}$. Let $Y$ = $\max\left ( X,0 \right )$ where $\max\left ( a,b \right )$ is the maximum of $a$ and $b$. The median of $Y$ is ______________ .
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Let $c_{1}.....c_{n}$ be scalars, not all zero, such that $\sum_{i=1}^{n}c_{i}a_{i}$ = 0 where $a_{i}$ are column vectors in $R^{n}$. Consider the set of linear equations $Ax = b$ where $A=\left [ a_{1}.....a_{n} \right ]$ ... set of equations has a unique solution at $x=J_{n}$ where $J_{n}$ denotes a $n$-dimensional vector of all 1. no solution infinitely many solutions finitely many solutions
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Instruction 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 ... . The speedup (correct to two decimal places) achieved by EP over NP in executing 20 independent instructions with no hazards is _________ .
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Consider the language $L$ given by the regular expression $(a+b)^{*} b (a+b)$ over the alphabet $\{a,b\}$. The smallest number of states needed in a deterministic finite-state automaton (DFA) accepting $L$ is ___________ .
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Consider the first-order logic sentence $F:\forall x(\exists yR(x,y))$. Assuming non-empty logical domains, which of the sentences below are implied by $F$? $\exists y(\exists xR(x,y))$ $\exists y(\forall xR(x,y))$ $\forall y(\exists xR(x,y))$ $¬\exists x(\forall y¬R(x,y))$ IV only I and IV only II only II and III only
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The n-bit fixed-point representation of an unsigned real number $X$ uses $f$ bits for the fraction part. Let $i = n-f$. The range of decimal values for $X$ in this representation is $2^{-f}$ to $2^{i}$ $2^{-f}$ to $\left ( 2^{i} - 2^{-f} \right )$ 0 to $2^{i}$ 0 to $\left ( 2^{i} - 2^{-f} \right )$
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Consider the following two functions. void fun1(int n) { if(n == 0) return; printf("%d", n); fun2(n - 2); printf("%d", n); } void fun2(int n) { if(n == 0) return; printf("%d", n); fun1(++n); printf("%d", n); } The output printed when $\text{fun1}(5)$ is called is $53423122233445$ $53423120112233$ $53423122132435$ $53423120213243$
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Let $A$ be an array of $31$ numbers consisting of a sequence of $0$'s followed by a sequence of $1$'s. The problem is to find the smallest index $i$ such that $A\left [i \right ]$ is $1$ by probing the minimum number of locations in $A$. The worst case number of probes performed by an optimal algorithm is ____________.
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Threads of a process share global variables but not heap heap but not global variables neither global variables nor heap both heap and global variables
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Let $u$ and $v$ be two vectors in R2 whose Euclidean norms satisfy $\left \| u \right \| = 2\left \| v \right \|$. What is the value of $\alpha$ such that $w = u + \alpha v$ bisects the angle between $u$ and $v$? $2$ $\frac{1}{2}$ $1$ $\frac{ -1}{2}$
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Consider the following context-free grammar over the alphabet $\Sigma = \{a,b,c\}$ with $S$ as the start symbol:$S \rightarrow abScT \mid abcT$$T \rightarrow bT \mid b$ ... $\{\left ( ab \right )^{n}\left ( cb^{n} \right )^{m} \mid m,n \geq 1 \}$
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A sender $S$ sends a message $m$ to receiver $R$, which is digitally signed by $S$ with its private key. In this scenario, one or more of the following security violations can take place. $S$ can launch a birthday attack to replace $m$ with a fraudulent ... replace $m$ with a fraudulent message Which of the following are possible security violations? I and II only I only II only II and III only
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Recall that Belady's anomaly is that the page-fault rate may increase as the number of allocated frames increases. Now, consider the following statement: $S1$: Random page replacement algorithm (where a page chosen at random is replaced) suffers from Belady's anomaly. $S2$: LRU page replacement ... $S1$ is true, $S2$is false $S1$ is false, $S2$is true $S1$ is false, $S2$is false
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Consider the Karnaugh map given below, where $X$ represents "don't care" and blank represents $0$. Assume for all inputs $\left ( a,b,c,d \right )$, the respective complements $\left ( \bar{a}, \bar{b}, \bar{c}, \bar{d} \right )$ are also available. The above logic is implemented using $2$-input $\text{NOR}$ gates only. The minimum number of gates required is ____________ .
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Consider a TCP client and a TCP server running on two different machines. After completing data transfer, the TCP client calls close to terminate the connection and a FIN segment is sent to the TCP server. Server-side TCP responds by sending an ACK, which is received by the ... does the client-side TCP connection wait for the FIN from the server-side TCP? LAST-ACK TIME-WAIT FIN-WAIT-1 FIN-WAIT-2
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Consider the $C$ struct defined below: struct data { int marks [100]; char grade; int cnumber; }; struct data student; The base address of student is available in register $R1$ ... mode, $R1$ Index addressing mode, $X(R1)$, where $X$ is an offset represented in $2's$ complement $16-bit$ representation
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When two 8-bit numbers $A_{7}...A_{0}$ and $B_{7}...B_{0}$ in 2's complement representation (with $A_{0}$ and $B_{0}$ as the least significant bits) are added using a ripple-carry adder, the sum bits obtained are $S_{7}...S_{0}$ and the carry bits are $C_{7}...C_{0}$. An overflow is said to ... $\left ( A_{0}.B_{0}.\bar{S_{0}}+\bar{A_{0}}.\bar{B_{0}}.S_{0} \right )$ is 1
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Consider a RISC machine where each instruction is exactly $4$ bytes long. Conditional and unconditional branch instructions use PC-relative addressing mode with Offset specified in bytes to the target location of the branch instruction. Further the Offset is always with respect to ... $i,$ then the decimal value of the Offset is ____________ .
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Let $T$ be a tree with $10$ vertices. The sum of the degrees of all the vertices in $T$ is ________
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Consider the following functions from positive integers to real numbers: $10$, $\sqrt{n}$, $n$, $\log_{2}n$, $\frac{100}{n}$. The CORRECT arrangement of the above functions in increasing order of asymptotic complexity is: $\log_{2}n$, $\frac{100}{n}$, $10$, $\sqrt{n}$, $n$ $\frac{100}{n}$, $10$ ... $\frac{100}{n}$, $\sqrt{n}$, $\log_{2}n$, $n$ $\frac{100}{n}$, $\log_{2}n$, $10$, $\sqrt{n}$, $n$
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Arun, Gulab, Neel and Shweta must choose one shirt each from a pile of four shirts coloured red, pink, blue and white respectively. Arun dislikes the colour red and Shweta dislikes the colour white. Gulab and Neel like all the colours. In how many different ways can they choose the shirts so that no one has a shirt with a colour he or she dislikes? $21$ $18$ $16$ $14$
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Consider a database that has the relation schema CR(StudentName, CourseName). An instance of the schema CR is as given below. ... $T2 \leftarrow CR\div T1$ The number of rows in $T2$ is ______________ .