GATE-CS-2007

Question 61

Consider the table employee(empId, name, department, salary) and the two queries Q1 ,Q2 below. Assuming that department 5 has more than one employee, and we want to find the employees who get higher salary than anyone in the department 5, which one of the statements is TRUE for any arbitrary employee table?

Q1 : Select e.empId
     From employee e
     Where not exists
        (Select * From employee s where s.department = “5” and 
                                        s.salary >=e.salary)
Q2 : Select e.empId
     From employee e
     Where e.salary > Any
    (Select distinct salary From employee s Where s.department = “5”)

• Q1 is the correct query
• Q2 is the correct query
• Both Q1 and Q2 produce the same answer.
• Neither Q1 nor Q2 is the correct query

Question 62

Which one of the following statements if FALSE?

• Any relation with two attributes is in BCNF
• A relation in which every key has only one attribute is in 2NF
• A prime attribute can be transitively dependent on a key in a 3 NF relation.
• A prime attribute can be transitively dependent on a key in a BCNF relation.

Question 63

The order of a leaf node in a tree B+ ? is the maximum number of (value, data record pointer) pairs it can hold. Given that the block size is 1K bytes, data record pointer is 7 bytes long, the value field is 9 bytes long and a block pointer is 6 bytes long, what is the order of the leaf node?

• 63
• 64
• 67
• 68

Question 64

Consider the following schedules involving two transactions. Which one of the following statements is TRUE?

• Both S1 and S2 are conflict serializable.
• S1 is conflict serializable and S2 is not conflict serializable.
• S1 is not conflict serializable and S2 is conflict serializable.
• Both S1 and S2 are not conflict serializable.

Question 65

There are n stations in a slotted LAN. Each station attempts to transmit with a probability p in each time slot. What is the probability that ONLY one station transmits in a given time slot?

• (1-p)^(n-1)
• np(1-p)^(n-1)
• p(1-p)^(n-1)
• 1-(1-p)^(n-1)

Question 66

In a token ring network the transmission speed is 10^7 bps and the propagation speed is 200 meters/micro second. The 1-bit delay in this network is equivalent to:

• 500 metres of cable.
  

• 200 metres of cable.
  

• 20 metres of cable.
  

• 50 metres of cable.
  

Question 67

The address of a class B host is to be split into subnets with a 6-bit subnet number. What is the maximum number of subnets and the maximum number of hosts in each subnet?

• 62 subnets and 262142 hosts.
• 64 subnets and 262142 hosts.
• 62 subnets and 1022 hosts.
• 64 subnets and 1024 hosts.

Question 68

The message 11001001 is to be transmitted using the CRC polynomial x^3 + 1 to protect it from errors. The message that should be transmitted is:

• 11001001000
• 11001001011
• 11001010
• 110010010011

Question 69

The distance between two stations M and N is L kilometers. All frames are K bits long. The propagation delay per kilometer is t seconds. Let R bits/second be the channel capacity. Assuming that processing delay is negligible, the minimum number of bits for the sequence number field in a frame for maximum utilization, when the sliding window protocolis used, is:

• A
• B
• C
• D

Question 70

Match the following:

(P) SMTP     (1) Application layer
(Q) BGP      (2) Transport layer
(R) TCP      (3) Data link layer
(S) PPP      (4) Network layer
             (5) Physical layer 

• P – 2 Q – 1 R – 3 S – 5
• P – 1 Q – 4 R – 2 S – 3
• P – 1 Q – 4 R – 2 S – 5
• P – 2 Q – 4 R – 1 S – 3