DipIETE – CS (NEW SCHEME)   –   Code: DC57

Subject: COMPUTER ORGANIZATION

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. 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       Choose the correct or the best alternative in the following:                                  (210)

             a.  When 2 n bit binary numbers are added the sum will contain at the most

(A) n bits (B) (n+1) bits

(C) (n+2) bits (D) n+n  bits

             b. The number  is numerically equivalent to  

(A) (B)

(C) (D)

             c.  RISC means

(A) Reduced Instruction Set Computing                                                                            

                  (B) Reduced Instruction Set Computer

(C) Reference Instruction Set Computer                                                                            

                  (D) Rated Instruction Set Computer

             d.  The 2 basic memory reference instructions are  

(A) Move & Store                                (B) Store & Copy

(C) Load & Store                                (D) Move & Load

             e.  In a digital computer, binary subtraction is performed

(A) In the same way as we perform subtraction in decimal number

                  (B) Using 2’s complement method

(C) Using 9’s complement method

                  (D) Using 10’s complement method

             f.   In a flow chart representation of a program diamond shaped box is used to indicate

(A) Decision to be taken by the computer

                  (B) Some processing operation

(C) Beginning or end of a program

                  (D) An I/O operation

             g.   Program counter pc always keeps the address of instruction

(A) to be executed next (B) which is being executed

(C) which has been executed (D) which is not executed

             h.  5 data bytes are pushed into a RAM stack beginning at address .  What is the top of the stack address after the data are loaded?

(A) (B)

(C) (D)

             i.   How many different locations can be selected using 16 address lines?

(A) 16 (B) 32

(C) 65536 (D) 4096                                                              

             j.   If an address code  is applied to 256 bit RAM which row and column will be selected?

(A) 12^th row & 9^th column (B) 9^th row & 12^th column

(C) 25^th row & 1^st column (D) 4^th row & 8^th column                                      

Answer any FIVE Questions out of EIGHT Questions.

Each question carries 16 marks.

  Q.2     a.   Explain different functional units of a digital computer. (10)

             b.   Convert the following pairs of decimal numbers to 5 bit signed 2’s complement binary numbers and add them.  State whether or not overflow occurs in each case:

(i)  -14 & 11                                       (ii)  -10 & -13                                    (3+3)

Q.3     a.   What is UART?  Draw a serial interface circuit that allows separate clock signals to be used for input and output operations.                                (10)

b.   Write a brief note on standard I/O interfaces.                                                      (6)

Q.4     a.   Explain encoding of machine instructions with example.                                     (10)

             b.   Register R5 is used in a program to point to the top of a stack.  Write a sequence of instruction using the index, auto increment and auto decrement addressing modes to perform

                   (i)   Remove the top 10 items from the stack.

                   (ii)  Copy the 5^th item from the top into register R3.                                        (3+3)

  Q.5     a.   Explain the process of enabling and disabling interrupts.                                      (8)

             b.   How is an I/O device converted to the bus?  Explain with diagram.                     (8)

Q.6     a.   Describe SDRAM & DDR SDRAM operations for data transfer between main memory and cache memory.                                                                                                                       (10)

             b.   What are the key factors that affect the performance and cost of a computer with respect to memory?  Explain briefly.                                     (6)

Q.7     a.   Explain Booth’s algorithm.  Multiply two  numbers – 13 (multiplicand) and 11 (multiplier) using normal and Booth’s multiplication method.             (10)

             b.   Explain the IEEE standard for floating point number.                                           (6)

  Q.8     a.   Explain the working principles of magnetic disk.                                                  (6)

             b.   What is n-bit ripple-carry adder?  Draw a block diagram and briefly explain its working.                 (10)

Q.9     a.   What are the major steps a processor has to perform to execute an instruction?  Explain briefly.                                                                 (6)

b.   With a neat diagram explain the hardwired control unit.                                     (10)