WBUT Previous Years Question Papers CS Computer Organization B Tech Third Sem 2008

WBUT  Previous Years Question Papers CS

Computer Organization B Tech Third Sem  2008


Time : 3 Hours ]

I Full Marks : 70

GROUP-A (Multiple Choice Type Questions)

  1. Choose the correct alternatives for the following :               .        10×1 = 10

J) When signed numbers Eire used In binary arithmetic then which one of the following notations would have unique representation for zero ?

a) Sign magnitude         b) l’s Complement

c) 2’s Complement         d) None of these.         ___ J

ii)        The logic circuitry in ALU is

a)         entirely combinational

b)         entirety sequential

c)         combinational cum sequential

d)         none of these.

iii)      In a micro-processor, the address of the next instruction to be executed, is . stored in

a)         Stack pointer

b)         Address latch                              •

c)         Program counter

d)         General purpose register.

iv)       The technique of placing software in a ROM semiconductor chip is called

‘ a) PROM           b) EPROM

c) FIRMWARE               d) Micro-Processor.

CS/B.TECH (CSEJ/SEM-3/CS-303/08/(09)

v)         Cache Memory

b)         increases performance

c)         reduces performance

vi)        Associative memory is a

a)         very cheap memory c) content addressable memory d) slow memory.

vii)      A single bus structure is primarily found in

a)   main frames   b) super computers

c) high performance machines d) mini and micro-computers.

viii)    Memory mapped I/O scheme is used for the allocation of address to memories and I/O devices is used for

a)  small system           b) large system

c) both large and small systems d) very large system.____

ix)       The convertion of ( FAFAFA ) 16 into octal form is

a)    76767676            b) 76575372

c) 76737672               d) 76727672.              [

x)         Which of the following addressing modes is used in the instruction PUSH B ?

a)         ‘ Immediate               b) Register

c)         Direct                    d) Register Indirect.

GROUP – B ( Short Answer Type Questions )

Answer any three of the following.    3×5=15

f . .

  1. Show the circuit diagram for implementing the following register transfer operation. If ( ab ~ = 1 ) then R1 «- R2 else R1 <- R3, where a and b are control variables.
  2. What do you mean by instruction cycle, machine cycles and T states ?
  3. What is virtual memory ? Why is it called virtual ? Write the advantage of virtual memory.                          2+1+2


  1. What are the advantages of microprogramming control over hardwared control ? What is the role of operating system ?                        »                                          3 + 2
  2. What are the different types of interrupt ? Give examples. What is programmed I/O technique? . ‘                                                                                      3 + 2

GROUP-C ( Long Answer Type Questions )

Answer any three of the following questions. 3×15 = 45

  1. a) What are Von Neumann concept and its bottleneck ?

b)         Represent the decimal value – 7-5 in IEEE – 754 single precision floating-point format.              ‘

c)         Compare parallel adder with serial adder.

d)         What is the necessity of guard bits ?

e)          Explain and draw the 4-bit binary decrementer circuit.    4 + 3 + 4+1 + 3

  1. a)  Draw the internal cell diagram of PROM and explain its functionality.

b)         What is cache memory ? How does it increase th^ performance of a computer ? What is hit ratio ?

c)         A three level memory system having cache access time of 5 nsec and disk access time of 40 nsec, has a cache hit ratio of 0-96 and main memory hit ratio

of 0-9. What should be, the main memory access time to achieve an overall


access time of 16 nsecv ? dj Define : (i) rotational latency, (ii) seek time.                                         4 + 4 + 5 + 2

  1. a) What is instruction cycle ? Draw the time diagram for memory write operation.

b)         Explain the basic DMA operations for transfer of data between memory and Peripherals.

c)         Evaluate the arithmetic statement X = ( A * B) / (C + D) in one, two and three address machines.                     1 + 4 + 5 + 5

  1. mapping, associative mapping and set-associative mapping cache schemes :
    a) Given the following, determine the size of the sub-fields in the address for direct

Main memory size              512 MB

Cache memory size             1 MB

,                Address space of processor 512 MB ‘

Block size .                        128 B

8 blocks in cache set.

b)          Differentiate between memory mapped I/O and I/O mapped I/O.

  1. Write short notes on any three of the following :

a)         Magnetic recording

b)          Cache replacement policies

c)          Non-restoring division method *

d)         Addressing modes                       .

e)          Booth’s algorithm.


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