GATE 2014 SET-2 CS Computer Science and information technology
[Q1 – Q25 carry ONE mark each ]
Q1➡| Engineering Mathematics The security system at an IT office is composed of 10 computers of which exactly four are working. To check whether the system is functional, the officials inspect four of the computers picked at random (without replacement). The system is deemed functional if at least three of the four computers inspected are working. Let the probability that the system is deemed functional be denoted by p. Then 100p =__________.
Q2➡| Engineering Mathematics Each of the nine words in the sentence “The quick brown fox jumps over the lazy dog” is written on a separate piece of paper. These nine pieces of paper are kept in a box. One of the pieces is drawn at random from the box. The expectedlength of the word drawn is _____________. (The answer should be rounded to one decimal place.)
Q6➡| Digital Logic Design The dual of a Boolean function F(x1, x2,…, xn, +, ∙ , ′ ), written as FD, is the same expression as that of F with + and ⋅ swapped. F is said to be self-dual if F = FD. The number of self-dual functions with n Boolean variables is
Q7➡| Digital Logic Design Let k = 2n. A circuit is built by giving the output of an n-bit binary counter as input to an n-to-2nbit decoder. This circuit is equivalent to a
Q9➡| Computer Organization A 4-way set-associative cache memory unit with a capacity of 16 KB is built using a block size of 8 words. The word length is 32 bits. The size of the physical address space is 4 GB. The number of bits for the TAG field is
Q11➡| Programming in C Suppose n and p are unsigned int variables in a C program. We wish to set p to nC3. If n is large, which one of the following statements is most likely to set p correctly?
Q12➡| Data Structure A priority queue is implemented as a Max-Heap. Initially, it has 5 elements. The level-order traversal of the heap is: 10, 8, 5, 3, 2. Two new elements 1 and 7 are inserted into the heap in that order. The level-order traversal of the heap after the insertion of the elements is:
Q14➡| Engineering Mathematics Consider the tree arcs of a BFS traversal from a source node W in an unweighted, connected, undirected graph. The tree T formed by the tree arcs is a data structure for computing
i ➥ the shortest path between every pair of vertices.
ii ➥ the shortest path from W to every vertex in the graph.
iii ➥ the shortest paths from W to only those nodes that are leaves of T
Q16➡| Theory of Computation Let A ≤N B denotes that language A is mapping reducible (also known as many-to-one reducible) to language B. Which one of the following is FALSE?
i ➥ If A ≤N B and B is recursive then A is recursive.
ii ➥ If A ≤N B and A is undecidable then B is undecidable.
iii ➥ If A ≤N B and B is recursively enumerable then A is recursively enumerable.
iv ➥ If A ≤N B and B is not recursively enumerable then A is not recursively enumerable
Q17➡| Compiler Design Consider the grammar defined by the following production rules, with two operators ∗ and + S ⟶ T ∗ P T ⟶ U | T ∗ U P ⟶ Q + P | Q Q ⟶ Id U ⟶ Id Which one of the following is TRUE?
i ➥ + is left associative, while ∗ is right associative
ii ➥ + is right associative, while ∗ is left associative
Q20➡| Operating System 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 x 106 bytes disk on which the file system is stored and data block size is 103 bytes, the maximum size of a file that can be stored on this disk in units of 106 bytes is .
Q23➡| Computer Network Which one of the following is TRUE about the interior gateway routing protocols – Routing Information Protocol (RIP) and Open Shortest Path First (OSPF)?
i ➥ RIP uses distance vector routing and OSPF uses link state routing
ii ➥ OSPF uses distance vector routing and RIP uses link state routing
iii ➥ Both RIP and OSPF use link state routing
iv ➥ Both RIP and OSPF use distance vector routing
Q25➡| Computer Network In the diagram shown below, L1 is an Ethernet LAN and L2 is a Token-Ring LAN. An IP packet originates from sender S and traverses to R, as shown. The links within each ISP and across the two ISPs, are all point-to-point optical links. The initial value of the TTL field is 32. The maximum possible value of the TTL field when R receives the datagram is .
Q26➡| Computer Network Consider the store and forward packet switched network given below. Assume that the bandwidth of each link is 106 bytes / sec. A user on host A sends a file of size 103 bytes to host B through routers R1 and R2 in three different ways. In the first case a single packet containing the complete file is transmitted from A to B. In the second case, the file is split into 10 equal parts, and these packets are transmitted from A to B. In the third case, the file is split into 20 equal parts and these packets are sent from A to B. Each packet contains 100 bytes of header information along with the user data. Consider only transmission time and ignore processing, queuing and propagation delays. Also assume that there are no errors during transmission. Let T1, T2 and T3 be the times taken to transmit the file in the first, second and third case respectively. Which one of the following is CORRECT?
An IP machine Q has a path to another IP machine H via three IP routers R1, R2, and R3.
Q—R1—R2—R3—H
H acts as an HTTP server, and Q connects to H via HTTP and downloads a file. Session layer encryption is used, with DES as the shared key encryption protocol. Consider the following four pieces of information:
[I1] The URL of the file downloaded by Q [I2] The TCP port numbers at Q and H [I3] The IP addresses of Q and H [I4] The link layer addresses of Q and H Which of I1, I2, I3, and I4 can an intruder learn through sniffing at R2 alone?
Q28➡| Computer Network A graphical HTML browser resident at a network client machine Q accesses a static HTML webpage from a HTTP server S. The static HTML page has exactly one static embedded image which is also at S. Assuming no caching, which one of the following is correct about the HTML webpage loading (including the embedded image)?
i ➥ Q needs to send at least 2 HTTP requests to S, each necessarily in a separate TCP connection to server S
ii ➥ Q needs to send at least 2 HTTP requests to S, but a single TCP connection to server S is sufficient
iii ➥ A single HTTP request from Q to S is sufficient, and a single TCP connection between Q and S is necessary for this
iv ➥ A single HTTP request from Q to S is sufficient, and this is possible without any TCP connection between Q and S
Q30➡|Database Management System Consider a join (relation algebra) between relations r(R)and s(S) using the nested loop method. There are 3 buffers each of size equal to disk block size, out of which one buffer is reserved for intermediate results. Assuming size(r(R))<size(s(S)), the join will have fewer number of disk block accesses if.
i ➥ relation r(R) is in the outer loop.
ii ➥ relation s(S) is in the outer loop.
iii ➥ join selection factor between r(R) and s(S) is more than 0.5.
iv ➥ join selection factor between r(R) and s(S) is less than 0.5.
Q32➡| Operating System Three processes A, B and C each execute a loop of 100 iterations. In each iteration of the loop, a process performs a single computation that requires tc CPU milliseconds and then initiates a single I/O operation that lasts for tio milliseconds. It is assumed that the computer where the processes execute has sufficient number of I/O devices and the OS of the computer assigns different I/O devices to each process. Also, the scheduling overhead of the OS is negligible. The processes have the following characteristics: . The processes A, B, and C are started at times 0, 5 and 10 milliseconds respectively, in a pure time sharing system (round robin scheduling) that uses a time slice of 50 milliseconds. The time in milliseconds at which process C would complete its first I/O operation is .
