WBUT Question Papers CS Advanced Computer Architecture B Tech Forth Sem 2011

WBUT Question Papers CS

 Advanced Computer Architecture B Tech Forth Sem 2011

Time Allotted : 3 Hours

Full Marks : 70

The figures in the margin indicate JuU marks.

Candidates are required to give their answers in their own words

as far as practicable.

GROUP – A ( Multiple Choice Type Questions )

  1. Choose the correct alternatives for any ten of the following :

. >’i) Consider the high speed 40 ns memory cache with a

successful hit ratio of 80 ns. The regular memory has an access time of 100 ns. What is the effective access time for CPU to access memory ?

‘ a) 52 ns                                        b) 60 ns

c) 70 ns                                   d) 80 ns.

[ Turn over


U) Assume a system where main memory is of size 16 K x 12 and eache memory is of size IK x 12. For a direet mapping ststem which statement is correct ?

a)          Tag field is 9 bits and index field is 6 bits

b)          Tag field is 4 bits and index field is 10 bits

c)          Tag field is 7 bits and index field is 8 bits

d)          None of these.

iii)        The advantage of RISC over CISC is that

a)          RISC can achieve pipeline segments, requiring just one clock cycle

b)          CISC uses many segments in its pipeline with the longest segment requiring two or more clock cycle

c)           Both (a) & (b)

d)          None of these.

iv)        The expression for Amadahl s law is

a)          S ( n) = 1//where n-> ~

b)          S ( n =/where n ->

c)           S ( n ) = 1/T where n~

d)          None of these.

v)           The vector stride value is required to

a)           deal with the length of vectors

b)           find the parallelism in vectors

C)     access the elements in multi-dimensional vectors

d)    execute vector instruction.

vi) Which MIMD systems are best according to scalability with respect to the number of processors ?

a)           Distributed memory computers

b)           ccNUMA systems

c)           nccNUMA systems

d)          Symmetric multiprocessors.

vil) In general an n input Omega network requires

stages of 2*2* switches.

a) 2                               b) 4

c) 8                               d) 16.

viii)      Dynamic pipeline allows

a)          Multiples function to evaluate

b)          Only streamline connection

c)           To perform fixed function

d)           None of fhese.

ix)        The performance of a pipeline processor suffers if

a)          the pipeline stages suffers different delay

. £ – ,

b)           consecutive instructions are dependent on each other

c)           the pipelining stages share same resources

d)          All of these.


x)           Superscalar processors have CPI ot

a) Less than 1                       b) Greater than 1

C) More than 2                        d) Greater than 3.

xi) The main memory of a computer has 2 cm blocks while the cache has 2 c blocks. If the cache uses the set associative mapping scheme with 2 blocks per set; then block k of the main memory maps to the set

a)           ( k mod m ) of the cache

b)           ( k mod c ) of the cache

c)           ( k mod 2c ) of the cache

d)           ( k mod 2 cm ) of the cache.

Xii) Overlapped register windows                 are used to speed up procedure call and return in

a)   RISC architecture b)      CISC architecture

c)   Both (a) and  (b)       d)  None of these.


GROUP -B ( Short Answer Type Questions )

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

  1. Discuss different types of vector instruction.
  2. What are the differences between loosely coupled and tightly coupled architecture ? What do you mean by non-uniform memory access, uniform memory access and memory bandwidth ?             2 + 3
  3. A 50 MHz processor was used to execute a program with the following instruction mix and clock cycle counts .

Instruction TYPe Instruction Count        Clock Cycle Count

Integer Arithmatic 50000                                     2

Data Transfer 70000                                            3

Floating point arithmetic 25000                          1

Branch 4000                                                        2

Calculate the effective CPI, MIPS rate and execution time fopr this program.                                                                      2 + 2+1

  1. Compare superscalar, super-pipeline & VLIW technique.
  2. What is the cache coherence problem ? Suggest one method to solve this problem.                                                             2 + 3

4201                                            5                                   [Turnover


GROUP -C ( Long Answer Type Questions )

Answer any three of the following.

7. What is pipeline ?

Consider the following reservation table :




3 4
SI X     X
S2   X    
S3     X  

wine uuwn                           *—-

vector. Draw the state diagram for scheduling the pipeline. Find out the sample cycle, greedy cycle and MAL. If the pipeline clock rate is 25 MHz, what is the throughput of the

DiDeline ? What are the bounds on MAL ?

FF                                                        2 + 2 + 3 + 3. + 2 + 3


8. a) What do you mean by MMX ? Differentiate a data flow computer from a control flow computer.

b)           List some potential problems with data flow computer implementation.

c)   With simple diagram explain data flow architecture.

d)           Draw data flow graphs to represent the following computations :

i)            P = X + Y

ii)          9 = p+y

ill)    R = X * P

iv)          S = R – Q

v)            T – R * P

vi)          U = S – T                                         2 + 2 + 3 + 5 + 3


9. What is the main difference and similarities between multi­computer and Multiprocessor ? Give the architecture for a typical MIMD processor ? Explain the shared memory modes of MIMD.               – V-                                          5 + 5 + 5

  1. What are the common data routing functions among the Processing Elements and how are they implemented ? Explain the main factors that can influence the Performance of interconnection networks. What are the different types of Multi-stage interconnection networks ?                   4 + 2 + 6 + a
  2. Write short notes on any three of the following :

i)                Flynn’s classification

ii)             Vector registers architectures

iii)          Write through and write back caches

iv)           Branch handling in instruction pipeline

v)              Pipeline hazards.

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