Test Papers / Previous Question Papers of IGNOU CS01 Computer Fundamentals December 2005

PGDCA / MCA (I Yr) / BCA
Term-End Examination

CS01 (S): Computer Fundamentals

Time: 3 hours
Maximum Marks: 75

1. (a) Draw the logic circuit for
Y = (ABAR+B) (A+B+CBAR)
Use Karnaugh's map to simplify the equation. Then draw the corresponding logic circuit using AND, OR, and NOT gates. (6)

(b) Write the syntax and explain the function of the following 8086 assembly language instructions: (6)
(i) REP
(ii) ROR
(iii) XOR
(iv) CMP

(c) Give an example of the addition of two floating point operands using an arithmetic pipeline. Show all the steps lnvolved. (6)

(d) Describe th€ following in the context of a multiprocessor system, giving an example of each: (6)

(i) Test, Set
(ii) Compare, Swap

(e) Explain the characteristics of highly encoded and unencoded microinstructions. (6)

2. (a) Show that the NOR gate is a functionally complete set of gates.

(b) Explain the difference between memory mapped I/O and I/O mapped I/O.

(c) Write an 8086 assembly language program to convert a two digit BCD number passed in AX to it's binary equivalent (5)

3. (a) An 8-bit reglster R1 contains 10101010. What should the value of the regisier R2 be such that the most significant 4-bits of R1 are
(i) selectively set?
(ii) selectively cleared?
(iii) selectively complemented?
{iv) masked?
Show the resulting operation (6)

(b) An 8-blt micro-processor has a 16-bit address bus.The tirst 15 lires of fhe address are used to select abank of 32 K bytes of memory. The high order bitof the address is used to select a register whichreceives the contents of a data bus. Explain how thisconfiguration can be used to extend the rnemorycapacity of the system of 8 banks of 32 K bytes eachfor a total of 256 K bytes of memory. (4)

(c) Daborate various addressing mechanisms of the 8086 micro-processor. Give an example of each type. (5)

4. (a) List four subcycles of an instruction cycle. Also list the various micro-operatlons of these subcycles. (6)

(b) What are the steps involved in programmed input/output ? Expiain the situations in which you would prefer Programmed lnput/output over Interrupt driven input/output. (6)

(c) Describe three characteristics of an MIMD multiprocessor that distinguish them from a multiple computer system. (3)

5. (a) What is the purpose ol making data flow graph ?
Make a data flow graph for
U = (X*(X + Y) - (X + Y)/Y)

(b) Explaln the following terms with the help of an example of diagram: (9)

(i) Single Error Correcting Code
(ii) Constant Linear Velocily (CLV) Disk Layout
(iii) Reset vector
(iv) Interrupt vector table
(v) Access Time for a magnetic disk
(vi) Floating point number format