Code:
DC04 Subject:
COMPUTER ORGANISATION
Time: 3 Hours Max. Marks: 100
NOTE: There are 9 Questions in all.
· Question 1 is compulsory and carries 20 marks. Answer to Q.1 A. must be written in the space provided for it in the answer book supplied and nowhere else.
· Out of the remaining EIGHT Questions answer any FIVE Questions. Each question carries 16 marks.
· Any required data not explicitly given, may be suitably assumed and stated.
Q.1 A. Choose the correct or best alternative in the following: (2x10)
a. In Reverse Polish notation, expression A*B+C*D is written as
(A) AB*CD*+ (B) A*BCD*+
(C) AB*CD+* (D) A*B*CD+
b. SIMD represents an organization that ______________.
(A) refers to a computer system capable of processing several programs at the same time.
(B) represents organization of single computer containing a control unit, processor unit and a memory unit.
(C) includes many processing units under the supervision of a common control unit
(D) none of the above.
c. Floating point representation is used to store
(A) Boolean values (B) whole numbers
(C) real integers (D) integers
d. Suppose that a bus has 16 data lines and requires 4 cycles of 250 nsecs each to transfer data. The bandwidth of this bus would be 2 Megabytes/sec. If the cycle time of the bus was reduced to 125 nsecs and the number of cycles required for transfer stayed the same what would the bandwidth of the bus?
(A) 1 Megabyte/sec (B) 4 Megabytes/sec
(C) 8 Megabytes/sec (D) 2 Megabytes/sec
e. Assembly language
(A) uses alphabetic codes in place of binary numbers used in machine language
(B) is the easiest language to write programs
(C) need not be translated into machine language
(D) None of these
f. In computers, subtraction is generally carried out by
(A) 9’s complement (B) 10’s complement
(C) 1’s complement (D) 2’s complement
g. The amount of time required to read a block of data from a disk into memory is composed of seek time, rotational latency, and transfer time. Rotational latency refers to
(A) the time its takes for the platter to make a full rotation
(B) the time it takes for the read-write head to move into position over the appropriate track
(C) the time it takes for the platter to rotate the correct sector under the head
(D) none of the above
h. What characteristic of RAM memory makes it not suitable for permanent storage?
(A) too slow (B) unreliable
(C) it is volatile (D) too bulky
i. Computers use addressing mode techniques for _____________________.
(A) giving programming versatility to the user by providing facilities as pointers to memory counters for loop control
(B) to reduce no. of bits in the field of instruction
(C) specifying rules for modifying or interpreting address field of the instruction
(D) All the above
j. The circuit used to store one bit of data is known as
(A) Register (B) Encoder
(C) Decoder (D) Flip Flop
Answer any FIVE Questions out of EIGHT Questions.
Each question carries 16 marks.
Q.2 a. Simplify the Boolean function F together with don’t care conditions d in sum-of-products and product-of-sum forms
(6)
b. Represent the condition control statement by two register transfer statements with control functions.
If (P=1) then 
else if (Q=1)
then 
(6)
c. Explain the use of subroutine with the help of suitable example. (4)
Q.3 a. Justify the statement “Stack computer consists of an operation code only with no address field”. (5)
b. Given that following are all the instructions related to AR, determine the control functions load(LD), clear(CLR) and increment(INC) for AR.
(6)
c. Explain indirect address mode and how the effective address is calculated in this case. (5)
Q.4 a. Why is read and write control lines in a DMA controller bidirectional? Under what condition and for what purpose are they used as inputs? (4)
b. Explain the different types of mapping procedures in the organization of cache memory with diagram. (12)
Q.5 a. What does the instruction field in the assembly language program specify? (3)
b. Explain the working of first pass of assembler using flow chart. (5)
c. Write a program in assembly language to subtract two integer numbers. (8)
Q.6 a. Explain the difference between vectored and non-vectored interrupt. Explain stating examples of each. (8)
b. Explain the various input output modes of data transfer. (8)
Q.7 a. Draw a flowchart for adding and subtracting two fixed point binary numbers where negative numbers are signed 1’s complement representation. (8)
b. Design a 4-bit combinational circuit decrementer using four full adders. (8)
Q.8 a. Differentiate between virtual and cache memory. (6)
b. Discuss Flynn’s classification of Computer (4)
c. A digital computer has a common bus system for 16 registers of 32 bits each. The bus is constructed with multiplexers.
(i) How many selection inputs are there in each multiplexer?
(ii) How many multiplexers are there in the bus? (6)
Q.9 a. Write a program to evaluate the arithmetic statement
(i) Using an accumulator type computer with one address instruction.
(ii)Using a stack organized computer with zero-address instructions. (8)
b. Explain the sequence that takes place when an interrupt occurs. (8)