MCA I (First) Semester Examination 2014-15

Course Code: MCA106 Paper ID: 0872104

Computer Organization and Architecture

Time: 3 Hours Max. Marks: 70 Max Marks: 75

Note: Attempt six questions in all. Q. No. 1 is compulsory.

1. Answer any five of the following (limit your answer in 50 words). (4x5=20)

a) Explain the concept of parity bits.

b) How floating point numbers are represented in computer?

c) Perform the following binary operations:

i) (567)8 = ( )2 ii) 1110001 + 0111101

d) Design the NAND gate circuit by using AND gates.

e) Define Canonical SOP and POS forms of any binary expression with suitable examples.

f) Explain various Shift micro operations used in systems.

g) Describe the three state bus buffer logic and its importance in data communication.

h) Why an Interface is required between processor and Input/Output?

2. a) Explain Demorgan’s Law of binary arithmetic. Also prove the laws with the help of binary laws. (5)

b) How sequential circuits are different from combinational circuits? Explain with the help of diagram and example. (5)

3. Differentiate any two: (5+5)

a) Encoders and Decoders

b) MUX and DEMUX

4. Define Registers. Explain the construction of registers. Describe various purpose and types of registers based on type of data stored. Why do we need RTL? Explain various rules of RTL with appropriate examples. Why it is preferred to have common bus system for transferring of data among various registers? (10)

5. a) Define addressing modes. Explain any four addressing modes used to retrieve the data. (5)

b) How instructions are different from microinstructions? List down various phases of instruction cycle and explain any first two phases in detail. (5)

6. a) How register reference instructions are distinguished from memory reference instructions? Give two examples of each type. (5)

b) What is handshaking? Why it is important in asynchronous data transfer? (5)

7. Define interrupts. Enlist any five interrupts generated while processing. Describe the concept of interrupt handling and interrupt prioritization. (10)

8. a) How programmed I/O is different from interrupt initiated I/O? (5)

b) Explain how usage of DMA enhances the system performance in terms of execution time. (5)