CS-01 Computer Fundamentals- Question Papers

MCA (I Yr.) - Term-End Examination

Note :
Time: 3 hours
There are six questions in this paper. Question number 1 is compulsory and carries 30 marks. Answer any three from the rest.

December 1999

Question 1

(a) Design an incrementer circuit, which takes a BCD digit (4 bit input) as input, increments the value and outputs the incremented value. For example if the BCD input is 0 that is 0000, it is incremented to 1 that is 0001, or if the BCD input is 9 that is 1001, it is incremented to 0 that is 0000, as the 5^th bit 1 is discarded. Also draw the resulting logic diagram. (10)

(b) Suppose a stack is to be used by CPU to manage subroutine calls and returns. Write a program segment in 8086 assembly which simulates parameter passing of one integer value of 16 bit and one floating point number of 32 bit. Print these values through the subroutine and then return to calling program and once again print the values from the calling program. (10)

(c) What is the role played by large register files in Reduced Instruction Set Computers? Can this role be done by having a large Cache? Justify your answer. (5)

(d) What are the usage of the following in the context of computer architecture: (5)

• Multiplexer and Decoder
• Addressing modes

Question 2

(a) Draw the logic diagram for an associative memory cell. (5)

(b) Draw the block diagram for a 4 bit adder-subtractor circuit. This circuit is to be fabricated using four full adder circuits and 4 exclusive OR gates. (5)

(c) Draw the logic diagram for a 3 bit synchronous counter. (5)

Question 3

(a) Write a program in 8086 assembly language to multiply a four digit packed BCD number with decimal digit 4. (5)

(b) What are the steps required for writing a memory resident Interrupt Servicing Routine for 8086 processor? Also explain the basic requirements of Interrupt Servicing Program. (5)

(c) Write a program in 8086 assembly language to check whether two strings are identical. (5)

Question 4

Compare and contrast the following: (15)

(a) Direct Memory Access versus Input-Output processor.

(b) Instruction and Arithmetic pipelining in array processors versus Instruction and Arithmetic pipelining in Reduced Instruction Set Computers.

(c)   (i) Static versus Dynamic RAMs
       (ii) 2D chip organisation versus 2 1/2D chip organisation.

(d)Horizontal micro instructions versus Vertical micro instructions.

(e) Associative Cache mapping versus Set Associative Cache mapping.

Question 5

(a) Design a floating-point representation for the following number ranges: (5)
Maximum number = 1 * 10²⁰
Minimum number = -1 * 10²⁰
The base of representation = 2
Zero needs to represented by this format.

(b) What is Cache coherence problem? Why is it important in shared-memory multi-processor systems? How can you resolve this problem? (5)

(c) Describe the following terminology in the context of multiprocessor systems: (5)

• Mutual Exclusion
• Critical Section
• Hardware Lock
• Semaphore
• Test and Set Instruction
  

Question 6

(a) Write short notes on the following: (14)

• RISC instructions
• Micro-operations
• Status bits and Flag register
• Interrupt vector table in 8086 microprocessor
• Bus arbitration
• Stored program concept
• Interrupts and Trap

(b) What is masking operation? Where is it used? Can masking be done by Exclusive OR operation? (1)