Q. The essential difference between traps and interrupts is

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Q. The size of the ROM required to build an 8-bit adder/subtractor with mode control, carry input, carry output and two's complement overflow output is given as

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Q. A specific editor has 200 K of program text, 15 K of initial stack, 50 K of initialized data, and 70 K of bootstrap code. If five editors are started simultaneously, how much physical memory is needed if shared text is used?

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Q. A hierarchical memory system that uses cache memory has cache access time of 50 nano seconds, main memory access time of 300 nano seconds, 75% of memory requests are for read, hit ratio of 0.8 for read access and the write-through scheme is used. What will be the average access time of the system both for read and write requests ?

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Q. For switching from a CPU user mode to the supervisor mode following type of interrupt is most appropriate

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Q. In a dot matrix printer the time to print a character is 6 m:sec., time to space in between characters is 2 m.sec., and the number of characters ina line are 200. The printing speed of the dot matrix printer in characters per second and the time to print a character line are given by which of the following options?

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Q. Match the following 8085 instructions with the flags:
 
a. XCHG i. only carry flag is affected.

b. SUB ii.  no flags are affected.

c. STC iii. all flags other than carry flag are affected.

d. DCR iv. all flags are affected.

code:
a  b  c   d

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Q. How many times will the following loop be executed?

          LXI    B, 0007 H
LOP: DCX  B 
          MOV  A,B
          ORA  C
          JNZ   LOP

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Q. Specify the contents of the accumulator and the status of the S, Z and CY flags when 8085 microprocessor performs addition of 87 H and 79 H.

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Q. Which of the following statements is not true?

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Q.  Consider the following statements :

(a) Boolean expressions and logic networks correspond to labelled acyclic digraphs.
(b) Optimal Boolean expressions may not correspond to simplest networks.
(c) Choosing essential blocks first in a Karnaugh map and then greedily choosing the largest remaining blocks to cover may not give an optimal expression.
Which of these statement(s) is/ are correct

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Q. Consider a full adder with the following input values :

(a) x=1, y=0 and Ci(carry input) = 0
(b) x=0, y=1 and Ci = 1
Compute the values of S(sum) and C0 (carry output) for the above input values.

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Q. In the case of parallelization, Amdahl's law states that if P is the proportion of the program that can be made parallel and (1 - P) is the proportion that cannot be parallelized , then the maximum speed that can be achieved by using N processors is

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Q. Which of the following statements is incorrect for Parallel Virtual Machine (PVM)?

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Q. Which of the following is not valid with reference to Message Passing Interface (MPI) ?

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Q. For the 8 - bit word 00111001, the check bits stored with it would be 0111. Suppose when the word is read from memory, the check bits are calculated to be 1101. What is the data word that was read from memory?

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Q. Consider a 32 - bit microprocessor, with a 16 - bit external data bus, driven by an 8 MHz input clock. Assume that this microprocessor has a bus cycle whose minimum duration equals four input clock cycles. What is the maximum data transfer rate for this microprocessor?

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Q. The RST 7 instruction in 8085 microprocessor is equivalent to :

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Q. The CPU of a system having 1 MIPS execution rate needs 4 machine cycles on an average for executing an instruction. The fifty percent of the cycles use memory bus. A memory read/ write employs one machine cycle. For execution of the programs, the system utilizes 90 percent of the CPU time. For block data transfer, an IO device is attached to the system while CPU executes the background programs continuously. What is the maximum IO data transfer rate if programmed IO data transfer technique is used?

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Q. The number of flip-flops required to design a modulo - 272 counter is :

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