As you want the placement paper of Computer Science of Indian Space Research Organisation [ISRO] so here I am providing you.

ISRO Computer Science placement paper

1. The Boolean expression Y = (A + B + AB) C is given by

_
(a) AC

_
(b) BC


_
(c) C


(d) AB



2. The circuit shown in the following Figure realizes the function

___ _ _
(a) (A+B+C) (D E)

___ _
(b) (A+B+C) (D E)

___ _
(c) (A+B+C) (D E)

_ _ _
(a) (A+B+C) (D E)



3. The circuit shown in the given Figure is a

(a) full adder

(b) full subtracter

(c) shift register

(d) decade counter



4. When two numbers are added in excess-3 code and the sum is less than 9, then in order to get the correct answer it is necessary to

(a) subtract 0011 from the sum

(b) add 0011 to the sum

(c) subtract 0110 from the sum

(d) add 0110 to the sum



5. The characteristic equation of an SR flip-flop is given by





6. A grap with "n" vertices and n-1 edges that is not a tree, is

(a) Connected

(b) Disconnected

(c) Euler

(d) A circuit



7. If a graph requires k different colours for its proper colouring, the the chromatic number of the graph is

(a) 1

(b) k

(c) k-1

(d) k/2



8. A read bit can be read

(a) and written by CPU

(b) and written by peripheral

(c) by pheripheral and written by CPU

(d) by CPU and written by the peripheral



9. Eigen vectors of







10. The term "aging" refers to

(a) booting up the priority of a process in multi-level of queue without feedback.

(b) gradually increasing the priority of jobs that wait in the system for a long time to remedy infinite blocking.

(c) keeping track of the following a page has been in memory for the purpose of LRU replacement

(d) letting job reside in memory for a certain amount of time so that the number of pages required can be estimated accurately.



11. Consider a set of n tasks with known runtimes r1, r2 ......... rn, to be run on a uniprocessor machine. Which of the following processor scheduling algorithms will result in the ma throughput ?

(a) Round Robin

(b) Shortest job first

(c) Highest response ratio next

(d) first cum first served



12. Consider a job scheduling problem with four jobs J1 J2 J3 and J4 with corresponding deadlines : (d1, d2, d3, d4) = (4,2,4,2)

Which of the following is not a feasible schedule without violating any job deadline ?

(a) J2, J4, J1, J3

(b) J4, J1, J2, J3

(c) J4, J2, J1, J3

(d) J4, J2, J3, J1



13. By using an eight bit optical encoder the degree of resolution that can be obtained is (approximately)

(a) 1.80

(b) 3.40

(c) 2.80

(d) 1.40



14. The principal of locality of reference justifies the use of

(a) virtual memory

(b) interrupts

(c) main memory

(d) cache memory



15. Consider the following psuedocode

x : = 1;

i : = 1;

while (x ? 1000)

begin

x : = 2x ;

i : = i + 1 ;

end ;

What is the value of i at the end of the pseudocode ?

(a) 4

(b) 5

(c) 6

(d) 7



16. The five items : A, B, C, D, and E are pushed in a stack, one after the other starting from A. The stack is popped four times and each element is inserted in a queue. Then two elements are deleted from the queue and pushed back on the stack. Now one item is popped from the stack. The popped item is

(a) A

(b) B

(c) C

(d) D



17. Round Robin scheduling is essentially the pre-emptive version of

(a) FIFO

(b) Shortest Job First

(c) Shortest remaining time

(d) Longest remaining time



18. The number of digit 1 present in the binary representation of 3 * 512 + 7 * 64 + 5 * 8 + 3 is

(a) 8

(b) 9

(c) 10

(d) 12



19. Assume that each character code consists of 8 bits. The number of characters that can be transmitted per second through an synchronous serial line at 2400 baud rate, and with two stop bits is

(a) 109

(b) 216

(c) 218

(d) 219



20. If the bandwidth of a signal is 5 kHz and the lowest frequency is 52 kHz, what is the highest frequency

(a) 5 kHz

(b) 10 kHz

(c) 47 kHz

(d) 57 kHz



21. An Ethernet hub

(a) functions as a repeater

(b) connects to a digital PBX

(c) connects to a token-ring network

(d) functions as a gateway



22. Phase transition for each bit are used in

(a) Amplitude modulation

(b) Carrier modulation

(c) Manchester encoding

(d) NRZ encoding



23. Study the following programme

// precondition : x > = 0

public void demo (int x)

{

System.out.print(x%10);

if ((x/10) ! = 0)

{

demo(x/10);

}

System.out.print(x%10);

}

Which of the following is printed as a result of the call demo (1234) ?

(a) 1441

(b) 3443

(c) 12344321

(d) 43211234



24. Bit stuffing refers to

(a) inserting a '0' in user stream to differentiate it with a flag

(b) inserting a '0' in flag stream to avoid ambiguity

(c) appending nibble to the flag sequence

(d) appending a nibble to the use data stream



25. What is the name of the technique in which the operating system of a computer executes several programs concurrently by switching back and forth between them ?

(a) Partitioning

(b) Multi tasking

(c) Windowing

(d) Paging



26. If there are five routers and six networks in an intranet using link state routing, how many routing tables are there ?

(a) 1

(b) 5

(c) 6

(d) 11



27. Virtual memory is

(a) Part of Main Memory only used for swapping

(b) A technique to allow a program, of size more than the size of the main memory, to run

(c) Part of secondary storage used in program execution

(d) None of these



28. The level of aggregation of information required for operational control is

(a) Detailed

(b) Aggregate

(c) Qualitative

(d) None of the above



29. The set of all Equivalence Classes of a set A of Cardinality C

(a) is of cardinality 20

(b) has the same cardinality as A

(c) forms a partition of A

(d) is of cardinality C2



30. 0.75 in decimal system is equivalent to __________ in octal system

(a) 0.60

(b) 0.52

(c) 0.54

(d) 0.50



31. In an SR latch made by cross coupling two NAND gates, if both S and R inputs are set to 0, then it will result in

(a) Q = 0, Q0 = 1

(b) Q = 1, Q0 = 0

(c) Q = 1, Q0 = 1

(d) Indeterminate states



32. Identify the correct translation into logical notation of the following assertion. Some boys in the class are taller than all the girls

Note: taller (x,y) is true if x is taller than y.

image - Computer Science - 2007 -Set A - Qno. 32 (a, b, c, d)



33. Company X shipped 5 computer chips, 1 of which was defective, and Company Y shipped 4 computer chips, 2 of which were defective. One computer chip is to be chosen uniformly at random from the 9 chips shipped by the companies. If the chosen chip is found to be defective, what is the probability that the chip came from Company Y ?

(a) 2/9

(b) 4/9

(c) 2/3

(d) 1/2



34. Ring counter is analogous to

(a) Toggle Switch

(b) Latch

(c) Stepping Switch

(d) S-R flip flop



35. The output 0 and 1 level for TTL Logic family is approximately

(a) 0.1 and 5 V

(b) 0.6 and 3.5 V

(c) 0.9 and 1.75 V

(d) -1.75 and 0.9 V



36. Consider a computer system that stores floating-point numbers with 16-bit mantissa and an 8-bit exponent, each in two's complement. The smallest and largest positive values which can be stored are

(a) 1 * 10-128 and 215 * 10128

(b) 1 * 10-256 and 215 * 10255

(c) 1 * 10-128 and 215 * 10127

(d) 1 * 10-128 and (215 - 1) * 10127



37. In comparison with static RAM memory, the dynamic RAM memory has

(a) lower bit density and higher power consumption

(b) higher bit density and higher power consumption

(c) lower bit density and lower power consumption

(d) higher bit density and lower power consumption



38. The Hexadecimal equivalent of 01111100110111100011 is

(a) CD73E

(b) ABD3F

(c) 7CDE3

(d) FA4CD



39. Disk requests are received by a disk drive for cylinder 5, 25, 18, 3, 39, 8 and 35 in that order. A seek taken 5 msec per cylinder moved. How much seek time is needed to serve these requests for a Shortest Seek First (SSF) algorithm ? Assume that the arm is at cylinder ?, 0 when the last of these requests is made with none of the requests yet served

(a) 125 msec

(b) 295 msec

(c) 575 msec

(d) 750 msec



40. Consider a system having 'm' resources of the same type. The resources are shared by 3 processes A, B, C, which have peak time demands of 3, 4, 6, respectively. The minimum value of 'm' that ensures that deadlock will never occur is

(a) 11

(b) 12

(c) 13

(d) 14