Information Technology - Online Test
Q1. Database table by name Loan_Records is given below.
Borrower Bank_Manager Loan_ Amount
Ramesh Sunderajan 10000.00
Suresh Ramgopal 5000.00
Mahesh Sunderajan 7000.00
What is the output of the following SQL query?
SELECT count(*)
FROM(
(SELECT Borrower. Bank_Manager FROM Loan_Records) AS S
NATURAL JOIN
(SELECT Bank_Manager, Loan_Amount FROM Loan_Records) AS T
);
Answer : Option C
Explaination / Solution:
After executing the given query, the output would be
Q2. On a non-pipelined sequential processor, a program segment, which is a part of
the interrupt service routine, is given to transfer 500 bytes from an I/O device to
memory.
Initialize the address register
Initialize the count to 500
LOOP: Load a byte from device
Store in memory at address given by address register
Increment the address register
Decrement the count
If count != 0 go to LOOP
Assume that each statement in this program is equivalent to a machine
instruction which takes one clock cycle to execute if it is a non-load/store
instruction. The load-store instructions take two clock cycles to execute.
The designer of the system also has an alternate approach of using the DMA
controller to implement the same transfer. The DMA controller requires 20 clock
cycles for initialization and other overheads. Each DMA transfer cycle takes two
clock cycles to transfer one byte of data from the device to the memory.
What is the approximate speedup when the DMA controller based design is used
in place of the interrupt driven program based input-output?
Answer : Option A
Explaination / Solution:
No. of clock cycles required by using load-store approach = 2 + 500 × 7 = 3502
and that of by using DMA = 20 + 500 × 2 = 1020
Required speed up = 3502/1020 = 3.4
Q3. Consider the following circuit involving three D-type flip-flops used in a certain type of counter configuration.
If at some instance prior to the occurrence of the clock edge, P. Q and R have a
value 0, 1 and 0 respectively, what shall be the value of PQR after the clock
edge?
Answer : Option D
Explaination / Solution:
From the Table Shown in the explanation of question 50, if first state is 010 next
State is 011
Q4. Let W(n) and A(n) denote respectively, the worst case and average case running time of an
algorithm executed on an input of size n. Which of the following is ALWAYS TRUE?
Answer : Option C
Explaination / Solution:
The average case time can be lesser than or even equal to the worst case. So A(n) would be
upper bounded by W(n) and it will not be strict upper bound as it can even be same (e.g.
Bubble Sort and merge sort).
∴A(n) = O(W(n))
Q5. An Internet Service Provider (ISP) has the following chunk of CIDR-based IP addresses
available with it: 245.248.128.0/20. The ISP wants to give half of this chunk of addresses to
Organization A, and a quarter to Organization B, while retaining the remaining with itself.
Which of the following is a valid allocation of address to A and B?
Answer : Option A
Explaination / Solution:
Since half of 4096 host addresses must be given to organization A, we can set 12th bit to 1
and include that bit into network part of organization A, so the valid allocation of addresses to
A is 245.248.136.0/21
Now for organization B, 12th bit is set to ‘0’ but since we need only half of 2048 addresses,
13th bit can be set to ‘0’ and include that bit into network part of organization B so the valid
allocation of addresses to B is 245.248.128.0/22
Q6. In a binary tree with n nodes, every node has an odd number of descendants.
Every node is considered to be its own descendant. What is the number of nodes
in the tree that have exactly one child?
Answer : Option D
Explaination / Solution:
No Explaination.
Q7. A thread is usually defined as a ‘light weight process’ because an operating
system (OS) maintains smaller data structures for a thread than for a process. In
relation to this, which of the followings is TRUE?
Answer : Option A
Explaination / Solution:
No Explaination.
Q8. Which of the following pairs have DIFFERENT expressive power?
Answer : Option B
Explaination / Solution:
NPDA is more powerful than DPDA.
Q9. Consider a database table T containing two columns X and Y each of type integer.
After the creation of the table, one record (X= 1, Y=l) is inserted in the table.
Let MX and MY denote the respective maximum values of X and Y among all
records in the table at any point in time. Using MX and MY, new records are
inserted in the table 128 times with X and Y values being MX+1, 2*MY+1
respectively. It may be noted that each time after the insertion, values of MX and
MY change.
What will be the output of the following SQL query after the steps mentioned
above are carried out?
SELECT Y FROM T WHERE X=7;
Answer : Option A
Explaination / Solution:
Q10. Register renaming is done is pipelined processors
Answer : Option C
Explaination / Solution:
Register renaming is done to eliminate WAR/WAW hazards.
