Question Paper of CS-64: Introduction to Computer Organisation

Ql(a). Perform the following arithmetic operations using 8-bit register. Use 2’s complement method. Indicate overflow or underflow if it occurs.
(i) 28 + (-28)
(ii) 26 (-26)
(iii) - 38 (90)
(iv) 25 90

(b) Construct the karnaugh’s map for the following function in term of various A, B, C, D. Find the optimal function using this map.

©Describe the need of a multiplexer in a system. How is a multiplexer different j-rom a decoder? Draw a logic diagram of a 2 * 1 multiplexer and 2 * 4 decoder.

(d) Write a program in 8086 to find the largest number in a list of integers stored in the memory. The program should output the number and its locution in the memory.

(e) How does the micro-programmed control unit of a computer function? Explain with the help of a block diagram.

(f) What is the need of having master-slave flip-flop? Example the working of a master-slave flip-flop with the help of logic diagram.

Q2(a). What is a bit slice? Where can it be used? Compare and contrast the features of Random Access to Direct Access. Give an example of Direct Access.

(b) Write a program in 8086 assembly language that compares two strings. The
program will output———1 if string 1 < string 2; 0 if both the stings are equal;
+ 1 if string 1> string 2.

© What is the head of a disk? List the various head mechanisms. Compare and contrast these mechanisms.
are the functional requirements of an I/O module? Explain briefly. Explain the interrupt driven Input/ Output.

(b) What are the advantages and disadvantages of evaluation-stack architecture? Describe the architecture with an example.

© What is the need of having many addressing modes in a machine? As a machine designer, select five most important addressing modes for your machine. Give reasons of your selection.

Q4(a). How is the memory read and write operation carried out using system bus? Write the necessary micro-operations for the above.

(b) Design a floating point number representation for the following:
Base: 2
Mantissa: Normalised
Precision : Single precision
Range of Exponent: 1 X 10�M
Range of mantissa: Equivalent to 5 decimal digits represented correctly
Exponent: Biased exponent
Assume that the word size of the above machine is 16 bits.

© What is firmware? How is it different from software? Describe the Wilkes
control unit.

Q5(a). Compare and contrast unencoded and highly encoded micro instructions.

(b) Write a 8086 assembly program to replace an uppercase letter by a lowercase letter. Make suitable assumptions, if any.

© What is the purpose of the queue in the bus interface unit of 8086 microprocessor?

Q6. Describe the following terms in the context of computer organisation and 8086 micro-processor:

(a) Linker Also called link editor and binder, a linker is a program that combines object
strong>(b) Associative memories
© Co-processor and peripheral processors

(e) Mask and Insert operation

(f)Mapping of cache blocks

Question Paper of CS-64: Introduction to Computer Organisation

Ql(a). Perform the following arithmetic operations on 8-bit numbers using signed 2’s complement notation. Indicate the overflow/underflow, if any.

(b) Simplify the following Boolean function in sum-of-product form by using four variable Karnaugh’s Draw the resultant logic diagram using AND-OR gates.

( c) The register of processor has the following values:
AL 0011 0011
BL 1100 1100
CL 1111 1111
DL 0000 1111
What will be the value of various registers, if the following operations are performed:

(i) Increment CL
(ii)Mask AL With DL
(iii) Selective set BL Using DL
(iv) Rotate arithmetic left DL
(v) Register AL = AL + BL (use new values)

(d) Write a program in 8086 assembly language to find the 10’s complement for a 2 digit packed BCD number. The number can be available in AL register.

(e) What is a micro-operation? How is the micro-operation different from an instruction ? Compare and contrast micro-operation with micro-instruction. Give an example each for an instruction, micro-operation and micro-instruction.

(f) How can two half adders be used (along with some other gates) for constructing all adder? Draw the resultant block diagram. How can you construct a 4-bit adder circuit using full adders? Draw the resultant block diagram.

Q2(a). Design a combinational circuit that generates an odd parity bit for the four
digit number input.

(b) Write program in 8086 assembly language to count the occurrence of vowels in a given string. You may assume that a 20 byte long string is available in the data segment of the program.

© What is the purpose of stack segment in an assembly program? How is the stack segment used for implementing procedure call?

Q3(a). How is the input/output performed from a disk using DMA module? What are the advantages of DMA for reading/writing from/to disks?

(b) The logical addresses used in 8086 are of 16 bit. whereas the actual physical addresses are of 20 bits. How is the 16 bit address mapped to a 20 bit address in 8086 micro-processor? Describe with help of an example. What are the advantages/ disadvantages of such addressing mechanisms?

© Design a floating point number representation for the following requirements:
Base of number: 2

Q4(a). What is the purpose of master-slave flip-flop? Draw the block diagram for the master slave flip-flop. Describe the functioning of the master slave flip-flop.

(b) Write a program in 8086 assembly language that finds the largest of the 10 given numbers in the data segment. The program also finds the average of these numbers. (Assume that numbers are only S bit and are in hexadecimal format).

© What is a BUS in the context of Computer Architecture? Draw the logic diagram of a 4 bit bus involving two input and output registers using multiplexers.

Q.5(a).What is the purpose of Single Error Correcting (SEC) code? Why do the ccur? What do we mean by error corrrection?

(b) What is the purpose of Cache memory in a computer? “Even if the size of Cache is sma’j, it increases the overall efficiency of a computer operation.” Comment on above statement giving reasons. Describe the associative cache mapping scheme.

© Compare and contrast the following:
(i’) Daisy chaining bus arbitration versus polling bus arbitration mechanism.

(ii) Flash memory versus ROM

(iii) Contact head mechanism versus Aerodynamic gap head mechanism.

Q6. Describe the following terms in the context the computer organisation and
8086 macro processor:
(a) Content Addressable Memory such Associative memory

(b) Multiplexer and Decoder

© Wilkes Control

(d) Input/Output Processor

(e) Interrupt mechanism

Question Paper of CS-64: Introduction to Computer Organisation

Ql(a). Perform the following arithmetic operations using 8-bit registers. Use 2’s complement method. Indicate overflow/underflow, if any.

(b) Simplify the following boolean function in sum-of-product form using four variable Karnaugh map. Draw the resulting logic diagram:
F(A,B,C,D)={(0,5,6,9,10,12,15)

© Describe tbt functioning of the basic R-S latch with the help of logic diagram. How can the ffip~flop be made synchronous (clocked)?

(d) Write a program in 8086 assembly language to find even number in the list of
10 numbers available in the data segment.

(e) What is the concept of segmentation in the context of 8086 micro-processor? How is a 16-bit address of 8086 micro-processor mapped to 20-bit physical address?

(f) What is the purpose of having micro-programmed control unit in a computer? How is the micro-program executed?

Question Paper of CS-64: Introduction to Computer Organisation

Ql(a). Perform the following arithmetic operation using 8-bit registers. Use 2’s complement method. Indicate overflow/underflow, if any:

(b) Simplify the following boolean function in sum of product form using four variable Karnaugh map. Draw the resulting logic diagram:

© What is the need of multiplexer in computers? Draw the block/logic diagram of a muiltiplexer and explain its functioning.

(d) Write a program in 8086 assembly language to reverse a string stored in the Data Segment. The reversed string should be stored in the location where the original string was stored.

(e) What is an Interrupt? How is the interrupt 21h used in 8086 microprocessor?

(f)What is a micro-instruction Compare and constrast the characteristics of horizontal micro-instruction to vertical micro-instructions.

Q2(a). What is a synchronous counter? How is it different from ripple counter? Where are ripple counters used? Draw the logic diagram for a 3bit ripple counter.

(b) Can a machine have zero address instruction? If yes, then explain its funtioning with an example. If no, then explain why not.

© Where a program in 8086 assembly language that adds two 2-digit packed BCDnumbers that are stored in data segment.

Q3(a). What is Programmed Input/Output? How is it different to that of Interrupt driven Input/Output? Can DMA module replace Programmed Input/Output module? Justify your answer.

(b) Describe the following addressing models with the help of an example

(i) Index-addressing mode
(ii) Relative-addressing mode
(iii) Indirect-addressing mode

©Design a combination circuit that converts a bit pattern as follows:

Q4(a). All instruction for execution are to be brought from the main memory to control unit register. Assuming a simple Von-Neumonn architecture machine, describe the steps of feeling the next instruction from the memory. Make suitable assumption, if any.

(b) What is the use of parity bit? Explain with the help of an example. What should be the length of the code that is nedded to correct one bit errors in a data of 8-bits?

©Design a floating point number format with the following reqirements: Base of the number: Mantissa : Should be able to represent upto 3 decimal
positions
Exponent: Approximately equivalent to 10+25
What will be the maximum and minimum positive and negative values being rep resented by your format? Make suitable assumptions, if any.

Q5(a). Write a program in 8086 assembly language that outputs a string stored in the memory in the data segment.

(b)Dra w the cicuit for 4 bit ROM having four words and explain the design.

© What is independent addressing scheme of bus arbitration? How is it different to polling? Which of the two is more advantageous? justify your answer.

Q6. Compare and construct the following:
(a) DMA versus Input/Output Processor

(b) Magnetic disk versus CD-ROM

© Associative cache mapping versus Set associative cache mapping

(d) Register addressing versus Memory addressing scheme.

(e) Master slave flip-flop versus A simple R-S flip-flop

Question Paper of CS-64: Introduction to Computer Organisation

Ql(a). Perform the following arithmetic operations using 8 bit registers. Use binary signed 1 ’s complement notation. Incdicate overflow/underflow, if any.

(b) Simplify the following boolean function in sum-of-product form using four variable Karnaugh’s map. Draw the resulting logic diagram.

F (A, B, C, D) = (0,5, 6,7, 8,9,10,11,12,15)

Please note that the symbol signifies the minterms whose decimal equivalent is listed in the parentheses. Produce a value 1 in the K map for the function.

© Describe the need of multiplexer in a system. How is a multiplexer different from a decoder? Draw the logic digram of a 2 x 1 multiplexer and 2x4 decoder.

(d) Write a program in 8086 assembly language to find whether a four digit Packed BCD number is divisible by either 3 or 5.

(e) How can you input intergers, characters and strings through keyboard for an assembly language (8086 assembly language) program? Explain with an example.

(f) What is a micro-operation? Is it related to a micro-instruction? What is a horizontal micro-insruction? What are the advantages of horizontal micro-instruction over vertical micro-instruction? Describe the term micro-program.

Q2(a). “ROM although is permanent memory, yet is a combinational circuit,” Justify the above statement by giving example of 2 word - 4 bit ROM. How is a cell of ROM different than that of RAM?

(b) Write a program in 8086 assembly language to find frequency of capital alphabets in a long string. Make suitable assumptions, if any.

© What is a zero address instruction? How can such instruction be executed? Describe a machine ogranisation which can have most of its instructions as zero address instructions.

Q3(a). What is the need of an Input/Output processor? Suggest a method by which an Input/Output processor can be connected to slow devices. Can an In put/Output processor be replaced by a DMA module? Justify your answer.

(b) Design a combinational circuit for a decision function, which takes four in put bit values and generates a value 1 if two or more bit values are 1; otherwise the function output a zero value. Draw the resulting logic diagram.

© What are the displacement addressing modes? Explain with help of an example each. Suggest the addressing modes that can be used in 8086 to handle arrays efficiently. Explain by giving an example.

Q4(a). Draw the logic circuit for one stage of full adder. Draw the block diagram for adding two four bit numbers.

(b) Write a program in 8086 assembly language to add two four digit unpacked BCD numbers.

© Design a floating point Dumber format for an following requirements: Base:2

Mantissa : Normalised, should be large enough to hold 4 significant decimal
digits.
Exponent: Based exponent in the range of + 25
Precision : Single
Make suitable assumptions, if any.

Q5(a). What is parity bit? How is it used in Single Error Correction Code? How
do you determine the size of SEC code for a given bit of data?

(b) Compare and constrasi the following:
(i) Associative memories versus Interleaved memories

(ii) 2D chip organisation versus 2 (1/2) D chipogranisation.

(iii) DRAM versus SRAM.

© What is arbitration? Describe the method of Polling arbitration. Compare and contrast Polling arbitration mechanism to that of Daisy chaining and Independent requesting.

Q6. Write short notes on the following :

(a) Mapping of Cache blocks

(b)Wilkes control

© Selective set, Selective mask and clear operations

(d) Fetch cycle of an instruction

(e) Peripheral processors and Co-processors

Question Paper of CS-64: Introduction to Computer Organisation

Ql(a). Perform the following arithmetic operations on 8 bit number using signed 2’s complement notation. Indicate the overflow and underflow, if any.

(b) Simplify the following Boolean function in sum-of-products form by using four variable karnaugh’s map. Draw the resultant logic diagram using AND-ORgates

F(A,B,C,D)= (0,5,6,7,9,10,15)

Please note that symbol means that the minterms that produce 1 for the function are listed as decimal equivalent of cell number in K-map, enclosed in the parentheses.

(d) What is meant by functionally complete set of gates ? Show that {NAND} is a
functionally complete set of gates.

(e) Write a program in 8086 assembly language to find that a given unpacked BCD number is even or odd.

(OWhat is Wilkes control ? How is it different from hardwired control ? What is a micro program ? How is a microprogram executed ?

Q2(a). Design a combinational circuit, which takes four input values and outputs a value 1, if the number of 1 ’s in the input values are odd; otherwise it output.

(b) Write a program in 8086 assembly language to count the number of decimal digits/ alphabets in a string. Make suitable assumption, if any.

© How can a stack be used for implementing a subroutine call ? Can this scheme be used to pass parameter also ? Justify your answer.

Q3(a). What is Interrupt Driven Input/Output ? How is it different from Direct Memory Access mechanism ? How is DMA module different from an I/O module ?

(b)What is the use of segment registers in 8086 microprocessor ? What are data segment and stack segment register? Where are they used ? Describe with the help of an example each. Why do 8086 need exta segment register ?

© Design a floating point number representation for the following :
Base : 2
Mantissa
Precision
Range of Exponent
Exponent

Q4(a), C sscribe the functioning of 3 x 8 decoder with the help of a logic diagram.

(b) What is a multiplexer ? Where is it used ? Draw the block diagram.

(d) Write a program in 8086 assembly language to convert a 2 digit BCD packet number to equivalent binary. Use INT function for input.

Q5(a). Describe the process of error detection and correction. What is the use of parity bit ? Can it be used in identifying the location of error? Justify your answer.

(b) What is the purpose of using Cache memory? What is set associative mapping of Cache ? Compare and contrast the set associative Cache mapping to that of associative Cache mapping schemes.

© Compare and contrast the following: (i) Various head mechanism of disks

(ii) Any three bus arbitration mechanisms

Q6. Write short notes on the following in the context of computer organisation and 80S6 micro processor: (a)Interrupt Vector Table (IVT)

(b)Vertical Micro-instruction

Vertical micro instruction :
Some characterstics of Vertical Microinstruction :-

© Mask and Insert operations

We are in the process of upadting this section for the question papers of BCA IGNOU

Ql (a). Perform the following arithmetic operations using 8-bit register. Use 2’s complement method. Indicate overflow or underflow if it occurs.

(b) Construct the karnaugh’s map for the following function in term of various A, B, C, D. Find the optimal function using this map.
F(A,B,C,D) = ?(2,6,10,14)
Draw the resulting logic diagram of the function.

©Describe the need of a multiplexer in a system. How is a multiplexer different j-rom a decoder? Draw a logic diagram of a 2 * 1 multiplexer and 2 * 4 decoder.

(d) Write a program in 8086 to find the largest number in a list of integers stored in the memory. The program should output the number and its locution in the memory.

(e) How does the micro-programmed control unit of a computer function? Explain with the help of a block diagram.

f) What is the need of having master-slave flip-flop? Example the working of a master-slave flip-flop with the help of logic diagram.

Ql(a). Do the arithmetic addition using binary 2’s complement notation in the following. Assume a register size of 8-bits. Indicate the state of overflow or underflow in each case.

(b) Show that {NOR} is a functionally complete set of gates. Use it to construct the OR, AND and NOT gates.

© Simplify the following Boolean function in the sum-of-product from using a Karnaugh map. Draw the resultant logic diagram using logic gates.
F(A,B,C,D) = 2(3,5,6>8,10,ll,14,15)

(d) The 8-bit registers in a processor have the following values:
AL—11110000
BL— 01000011
CL— 00110011
DL—11110001
What will the values of the register be when the following operations are per formed?

(e)Write a program in 8086 Assembly Language that takes three numbers (of size 8 bits) stored in data segment, calculates their average and then outputs the result on the monitor.

Image no.5

Define the IEEE 754 floating point number standard giving the single and Viouble’prerision floating point number bit’s layout and bias of exponent Also show an example each of addition and subtraction of two floating-point numbers. IEEE Standard Floating Point Float:

Q2 a) You are given four 3X8 decoders. Design a 5X32 decoder using these four decoders.

(b) Write an 8086 assembly program that checks whether a small string is a substring ofa larger string. You may assume a 20-byte long string and a 4-byte long sub-string in the data segment of the program.

© What is a microinstruction? How is it different from an instruction? What formats are used for microinstructions? Explain with the help of an example each.

Q3(a).Explain two major differences between a synchronous and asynchronous Draw the logic diagram of a 4-bit ripple counter.

(B) Give one example (from 8086):
(i) Immediate addressing mode
(ii) Direct addressing mode
(iii) Register-indirect addressing mode
(iv) Based-indirect addressing mode
(v) Based-indexed addressing modi

©.How can a parity bit be used for checking error in a single bit? Example the Process with the help of a diagram.

(d) What are the advantages/disadvantages of using a Parity bit?

(e) How is a parity bit related to a single-error correcting code?

Q4(a). Give at least two advantages/disadvantages of using a higher number of operand addresses in a machine instruction. What is evaluation stack architec ture? Explain with the help of an example, how this machine can be used for evaluating an expression A * B + C - D.

(b)Write a procedure in 8086 assembly which sums 2 numbers passed as parameters to it and returns the result. Also, write the relevant calling code in the calling assembly program. Make suitable assumptions, if any.

© What is the mechanism of handling Interrupt driven Input/Output? Explain using a flow chart. What methods can be used to handle multiple interrupts?

Q5(a). What is RAID? What are RAID levels? Explain any two giving data distribution and advantages/disadvantages of that level.

(b) What is a Bus? Why is it used? How does Bus size influence size of memory addresses? Explain any one Bus arbitration scheme.

© (i) What are the differences in representation of Floating point and Fixed point “umbers?

(ii) What are the four important differences between associative mappings and set associative mapping in cache?

(iii) List three important differences between CRT (Cathode Ray Tube) and LCD (Liquid Crystal Display) displays.

Q6. Describe the following in the context of computer organization and 8086 microprocessor, with the help of an example, if necessary:

(i) Use of Interrupt 21H for data string input

(ii) Characteristics of von Neumann machine

(iii) Types of programmer visible registers.

(iv) Selective complement and Insert operation

(v) Addition of two 8-bit register in 8086 having packed BCD numbers