CS-01 Computer Fundamentals- Sample 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.

Question 1

(a) Suppose you have two 4 x 1 multiplexer circuits, and one decoder. Construct a 8 x 1 multiplexer circuit using these circuits. Assume the necessary number of select lines and enable lines. (5)

(b) "A subroutine call can be implemented by specifying a location in subroutine for storing the return address." Comment on the above statement. Suggest a scheme through which parameters can also be passed during a subroutine call. (5)

(c) Suppose a machine is not allowed to have stack implementation. Suggest five addressing modes for this machine. Explain your selection. (5)

(d) Write a program in 8086 assembly language to convert a two digit BCD packed number to equivalent binary. (5)

(e) What are the advantages and disadvantages of having multiprocessor systems? Explain one interconnection structure for multiprocessor systems. (5)

(f) An eight-bit register contains a value 01111000. What will be the value of register if the following operations are performed in sequence on the register: (5)

• Arithmetic shift right.
• Logical shift right.
• Circular shift right.
• Masking of lower nibble
• Clearing of upper nibble.

Show all the steps. Assume the presence of another register B. Make suitable assumptions, if any.

Question 2

(a) Draw the logic diagram for a 4 bit -2 word ROM having values 1010 and 0101. (5)

(b) Write a program in 8086 assembly language to multiply a 2 digit unpacked BCD number with a value 4. The result should be an unpacked BCD value. (5)

(c) What does the term vector processing mean? Can vector processing be done on a Uniprocessor System? Justify your answer. What kind of pipeline will you suggest for vector processing hardware support? (5)

Question 3

(a) Interrupt driven input/output and DMA both require an Interrupt. How are the two different in responding to the Interrupt? Compare and contrast the features of DMA to that of Interrupt driven I/O. (5)

(b)What is Bus Arbitration? What is polling in the context of bus arbitration? How is it different from Daisy chaining? Can these two methods of bus arbitration be used in multiprocessor systems? Justify your answer. (5)

(c) Write an algorithm in 8086 assembly language to count the number of alphabets In a string. Make suitable assumptions, if any. (5)

Question 4

(a) Design a combinational circuit for a "Minority Function" having 3 input values. The output is the value that is in minority. For example, input values 101 will result in output as 0, whereas input value 001 will result in output as 1. (5)

(b) Write a program in 8086 assembly language that calls a subroutine "add" that adds two numbers stored in AX and BX registers. Also show the stack values on subroutine call. (5)

(c) What is Inter-processor Synchronization? How is Mutual Exclusion mechanism followed in Multiprocessor System? (5)

Question 5

(a) What is Wilkes Control? How is it different from hardwired control? Can micro programming be used in RISC? Justify your answer. (5)

(b) Compare and contrast large register file used in RISC versus Cache memory available in CISC. Why is RISC pipeline optimized? What are the problems with RISC pipelining? (5)

(c) Design a floating-point single precision number with the following requirements: (5)

Base of number: 2
Precision: At least equivalent to 3 decimal digits
Exponent: 10^±25

Make suitable assumptions, if any.

Question 6

Compare and contrast the following: (15)

1. Memory hierarchy versus Memory interleaving.
2. Flash memories versus EEPROMs.
3. Access method on main memory versus Access methods of secondary storage.
4. Input / Output processor versus Peripheral processor.
5. J-K flip-flop versus R-S flip-flop.
6. Various head mechanisms on disks.