GATE-CS-2014-(Set-2)

Question 31

Given the STUDENTS relation as shown below. 

[caption width="800"] [/caption]

For (StudentName, StudentAge) to be the key for this instance, the value X should not be equal to

• 18

• 19

• 17

• 20

Question 32

Which one of the following is TRUE about interior Gateway routing protocols - Routing Information Protocol (RIP) and Open Shortest Path First (OSPF)

• RIP uses distance vector routing and OSPF uses link state routing
• OSPF uses distance vector routing and RIP uses link state routing
• Both RIP and OSPF use link state routing
• Both RIP and OSPF use distance vector routing

Question 33

Which one of the following socket API functions converts an unconnected active TCP socket into a passive socket.

• connect
• bind
• listen
• accept

Question 34

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 link within each ISP, and across two ISPs, are all point to point optical links. The initial value of TTL is 32. The maximum possible value of TTL field when R receives the datagram is

• 25
• 24
• 26
• 28

Question 35

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? 

[caption width="800"] [/caption]

• T1 < T2 < T3

• T1 > T2 > T3

• T2 = T3, T3 < T1

• T1 = T3, T3 > T2

Question 36

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?

• Only I1 and I2
• Only I1
• Only I2 and I3
• Only I3 and I4

Question 37

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)?

• Q needs to send at least 2 HTTP requests to S, each necessarily in a separate TCP connection to server S
• Q needs to send at least 2 HTTP requests to S, but a single TCP connection to server S is sufficient
• A single HTTP request from Q to S is sufficient, and a single TCP connection between Q and S is necessary for this
• A single HTTP request from Q to S is sufficient, and this is possible without any TCP connection between Q and S

Question 38

Consider the following schedule S of transactions T1, T2, T3, T4: Which one of the following statements is CORRECT?

• S is conflict-serializable but not recoverable
• S is not conflict-serializable but is recoverable
• S is both conflict-serializable and recoverable
• S is neither conflict-serializable nor is it recoverable

Question 39

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

• relation r(R) is in the outer loop.

• relation s(S) is in the outer loop.

• join selection factor between r(R) and s(S) is more than 0.5.

• join selection factor between r(R) and s(S) is less than 0.5.

Question 40

Consider the procedure below for the Producer-Consumer problem which uses semaphores: Which one of the following is TRUE?

• The producer will be able to add an item to the buffer, but the consumer can never consume it.
• The consumer will remove no more than one item from the buffer.
• Deadlock occurs if the consumer succeeds in acquiring semaphore s when the buffer is empty.
• The starting value for the semaphore n must be 1 and not 0 for deadlock-free operation.