UGC NET CS 2016 July – III

Question 1

Which of the following is a sequential circuit?

• A. Multiplexer
• B. Decoder
• C. Counter
• D. Full adder

Answer: (C)

• Multiplexer, Decoder and Full adder are example of combinational circuits.
• Counter is a Sequential circuit.

For more information on sequential circuits Refer:Digital Logic | Introduction of Sequential Circuits Option (C) is correct.

Question 2

8085 microprocessor has _____ hardware interrupts.

• A. 2
• B. 3
• C. 4
• D. 5

Answer: (D)

8085 microprocessor has 5 hardware interrupts. Named TRAP, RST 7.5, RST 6.5, RST 5.5 and INTR. 8086 microprocessor has 2 hardware interrupts. Named NMI and INTR. So, option (D) is correct.

Question 3

Which of the following in 8085 microprocessor performs HL = HL + DE ?

• A. DAD D
• B. DAD H
• C. DAD B
• D. DAD SP

Answer: (A)

DAD will perform Double addition (16 bit) between HL pair and any other pair of register. Among HL, BC, DE and SP; B, H and D register will be used first. So, DAD H will do HL = HL + HL; DAD B will do HL = HL + BC; DAD D will do HL = HL + DE; SP is stack pointer and it is not a pair register, DAD SP will do HL = HL + SP; So, option (A) is correct.

Question 4

The register that stores all interrupt requests is:

• A. Interrupt mask register
• B. Interrupt service register
• C. Interrupt request register
• D. Status register

Answer: (C)

• The register that stores all interrupt requests is Interrupt request register.
• Interrupt mask register is a read and write register. This register enables or masks interrupts from being triggered on the external pins of the Cache Controller.
• Interrupt service register handle the interrupt and service them according to priority and other condition.
• Status register is a hardware register that contains information about the state of the processor
So, option (C) is correct.

Question 5

The _____ addressing mode is similar to register indirect addressing mode, except that an offset is added to the contents of the register. The offset and register are specified in the instruction.

• A. Base indexed
• B. Base indexed plus displacement
• C. Indexed
• D. Displacement

Answer: (D)

• The displacement addressing mode is similar to register indirect addressing mode, except that an offset is added to the contents of the register. The offset and register are specified in the instruction.
• Based Indexed Addressing: The operand’s offset is sum of the content of a base register BX or BP and an index register SI or DI.
• Based Indexed plus displacement addressing mode: In this mode of addressing the operand’s offset is given by offset=[BX or BP]+[SI or DI]+8 bit or 16 bit displacement.
• Indexed addressing mode: The operand’s offset is the sum of the content of an index register SI or DI and an 8 bit or 16 bit displacement.

So, option (D) is correct.

Question 6

In _____ method, the word is written to the block in both the cache and main memory, in parallel.

• A. Write through
• B. Write back
• C. Write protected
• D. Direct mapping

Answer: (A)

In write through method, the word is written to the block in both the cache and main memory, in parallel and in write back method the word is written to the block in cache but actual update into the corresponding location in main memory only at specified intervals or under certain conditions. In Write Protected cache policy word cannot be modified or deleted.
In direct mapping block M of main memory maps into block M modulo n of the cache, where n is the total number of blocks in cache. So, option (A) is correct.

Question 7

Which of the following statements concerning Object-Oriented databases is FALSE?

• A. Objects in an object-oriented database contain not only data but also methods for processing the data.
• B. Object-oriented databases store computational instructions in the same place as the data.
• C. Object-oriented databases are more adapt at handling structured (analytical) data than relational databases.
• D. Object-oriented databases store more types of data than relational databases and access that data faster.

Answer: (C)

• Objects in an object-oriented database contain not only data but also methods for processing the data.Correct
• Object-oriented databases store computational instructions in the same place as the data.Correct
• Object-oriented databases are more adapt at handling structured (analytical) data than relational databases.Incorrect
• Object-oriented databases store more types of data than relational databases and access that data faster.Correct

So, option (C) is correct.

Question 8

In distributed databases, location transparency allows for database users, programmers and administrators to treat the data as if it is at one location. A SQL query with location transparency needs to specify:

• A. Inheritances
• B. Fragments
• C. Locations
• D. Local formats

Answer: (B)

Question 9

Consider the relations R(A, B) and S(B, C) and the following four relational algebra queries over R and S: I. Π_{A, B} (R ⨝ S) II. R ⨝ Π_B(S) III. R ∩ (Π_A(R) × Π_B(S)) IV. Π_{A, R.B} (R × S) where R⋅B refers to the column B in table R. One can determine that:

• A. I, III and IV are the same query.
• B. II, III and IV are the same query.
• C. I, II and IV are the same query.
• D. I, II and III are the same query.

Answer: (D)

Question 10

Which of the following statements is TRUE? D₁ : The decomposition of the schema R(A, B, C) into R₁(A, B) and R₂ (A, C) is always lossless. D₂ : The decomposition of the schema R(A, B, C, D, E) having AD → B, C → DE, B → AE and AE → C, into R₁ (A, B, D) and R₂ (A, C, D, E) is lossless.

• A. Both D₁ and D₂
• B. Neither D₁ nor D₂
• C. Only D₁
• D. Only D₂

Answer: (D)

Only D2 is True because AD is key and present in both the tables. D1 is not always true because FD’s not given and if we take B->A and C->A then it is lossy decomposition because no common attributes contain key from one of the table.