PGT-COMPUTER
SCIENCE
UNIT:1 COMPUTER
SYSTEM ARCHITECTURE SET1-230 MCQ
1. In Reverse Polish
notation, expression A*B+C*D is written as
(A) AB*CD*+
(B) A*BCD*+
(C) AB*CD+*
(D) A*B*CD+
Ans: A
2. SIMD represents an
organization that ______________.
(A) refers to a computer
system capable of processing several programs at the same time.
(B) represents
organization of single computer containing a control unit, processor unit and a
memory unit.
(C) includes many
processing units under the supervision of a common control unit
(D) none of the above.
Ans: C
3. Floating point
representation is used to store
(A) Boolean values
(B) whole numbers
(C) real integers
(D) integers
4. Suppose that a bus
has 16 data lines and requires 4 cycles of 250 nsecs each to transfer data.
The bandwidth of this
bus would be 2 Megabytes/sec. If the cycle time of the bus was reduced to 125
nsecs and the number of cycles required for transfer stayed the same what would
the bandwidth of the bus?
(A) 1 Megabyte/sec
(B) 4 Megabytes/sec
(C) 8 Megabytes/sec
(D) 2 Megabytes/sec
Ans: D
5. Assembly language
(A) uses alphabetic
codes in place of binary numbers used in machine language
(B) is the easiest
language to write programs
(C) need not be
translated into machine language
(D) None of these
Ans: A
6. In computers,
subtraction is generally carried out by
(A) 9’s complement
(B) 10’s complement
(C) 1’s complement
(D) 2’s complement
Ans: D
7. The amount of time
required to read a block of data from a disk into memory is composed of seek
time, rotational latency, and transfer time. Rotational latency refers to
(A) the time its takes
for the platter to make a full rotation
(B) the time it takes
for the read-write head to move into position over the appropriate track
(C) the time it takes
for the platter to rotate the correct sector under the head
(D) none of the above
Ans: A
8. What characteristic
of RAM memory makes it not suitable for permanent storage?
(A) too slow
(B) unreliable
(C) it is volatile
(D) too bulky
Ans: C
9. Computers use
addressing mode techniques for _____________________.
(A) giving programming
versatility to the user by providing facilities as pointers to memory counters
for loop control
(B) to reduce no. of
bits in the field of instruction
(C) specifying rules for
modifying or interpreting address field of the instruction
(D) All the above
Ans: D
10. The circuit used to
store one bit of data is known as
(A) Register
(B) Encoder
(C) Decoder
(D) Flip Flop
Ans: D
11. (2FAOC) 16 is
equivalent to
(A) (195 084) 10
(B) (001011111010 0000
1100) 2
(C) Both (A) and (B)
(D) None of these
Ans: B
12. The average time
required to reach a storage location in memory and obtain its contents is
called the
(A) seek time
(B) turnaround time
(C) access time
(D) transfer time
Ans: C
13. Which of the
following is not a weighted code?
(A) Decimal Number
system
(B) Excess 3-cod
(C) Binary number System
(D) None of these
Ans: B
14. The idea of cache
memory is based
(A) on the property of
locality of reference
(B) on the heuristic
90-10 rule
(C) on the fact that
references generally tend to cluster
(D) all of the above
Ans: A
15. Which of the
following is lowest in memory hierarchy?
(A) Cache memory
(B) Secondary memory
(C) Registers
(D) RAM
(E) None of these
Ans (B) Secondary memory
16. The addressing mode
used in an instruction of the form ADD X Y, is
(A) Absolute
(B) indirect
(C) index
(D) none of these
Ans: C
17. If memory access
takes 20 ns with cache and 110 ns with out it, then the ratio (cache uses a 10
ns memory) is
(A) 93%
(B) 90%
(C) 88%
(D) 87%
Ans: B
18. In a memory-mapped
I/O system, which of the following will not be there?
(A) LDA
(B) IN
(C) ADD
(D) OUT
Ans: A
19. In a vectored
interrupt.
(A) the branch address
is assigned to a fixed location in memory.
(B) the interrupting
source supplies the branch information to the processor through an interrupt
vector.
(C) the branch address
is obtained from a register in the processor
(D) none of the above
Ans: B
20. Von Neumann
architecture is
(A) SISD
(B) SIMD
(C) MIMD
(D) MISD
Ans: A
21. The circuit used to
store one bit of data is known as
(A) Encoder
(B) OR gate
(C) Flip Flop
(D) Decoder
Ans: C
22. Cache memory acts
between
(A) CPU and RAM
(B) RAM and ROM
(C) CPU and Hard Disk
(D) None of these
Ans: A
23. Write Through technique
is used in which memory for updating the data
(A) Virtual memory
(B) Main memory
(C) Auxiliary memory
(D) Cache memory
Ans: D
24. Generally Dynamic
RAM is used as main memory in a computer system as it
(A) Consumes less power
(B) has higher speed
(C) has lower cell
density
(D) needs refreshing
circuitary
Ans: B
25. In signed-magnitude
binary division, if the dividend is (11100) 2 and divisor is (10011) 2 then the
result is
(A) (00100) 2
(B) (10100) 2
(C) (11001) 2
(D) (01100) 2
Ans: B
26. Virtual memory
consists of
(A) Static RAM
(B) Dynamic RAM
(C) Magnetic memory
(D) None of these
Ans: A
27. In a program using
subroutine call instruction, it is necessary
(A) initialise program
counter
(B) Clear the
accumulator
(C) Reset the
microprocessor
(D) Clear the
instruction register
Ans: D
28. A Stack-organised
Computer uses instruction of
(A) Indirect addressing
(B) Two-addressing
(C) Zero addressing
(D) Index addressing
Ans: C
29. If the main memory
is of 8K bytes and the cache memory is of 2K words. It uses associative
mapping.
Then each word of cache memory shall be
(A) 11 bits
(B) 21 bits
(C) 16 bits
(D) 20 bits
Ans: C
30 A-Flip Flop can be
converted into T-Flip Flop by using additional logic circuit
(A) n TQD =•
(B) T D =
(C) D = T . Q n
(D) n TQD =?
Ans: D
31. Logic X-OR operation
of (4ACO) H & (B53F) H results
(A) AACB
(B) 0000
(C) FFFF
(D) ABCD
Ans: C
32. When CPU is
executing a Program that is part of the Operating System, it is said to be in
(A) Interrupt mode
(B) System mode
(C) Half mode
(D) Simplex mode
Ans: B
33. An n-bit
microprocessor has
(A) n-bit program
counter
(B) n-bit address
register
(C) n-bit ALU
(D) n-bit instruction
register
Ans: D
34. Cache memory works
on the principle of
(A) Locality of data
(B) Locality of memory
(C) Locality of
reference
(D) Locality of
reference & memory
Ans: C
35. The main memory in a
Personal Computer (PC) is made of
(A) cache memory.
(B) static RAM
(C) Dynamic Ram
(D) both (A) and (B) .
Ans: D
36. In computers,
subtraction is carried out generally by
(A) 1’s complement
method
(B) 2’s complement
method
(C) signed magnitude
method
(D) BCD subtraction
method
Ans: B
37. PSW is saved in
stack when there is a
(A) interrupt recognised
(B) execution of RST
instruction
(C) Execution of CALL
instruction
(D) All of these
Ans: A
38. The multiplicand
register & multiplier register of a hardware circuit implementing booth’s
algorithm have (11101) & (1100). The result shall be
(A) (812) 10
(B) (-12) 10
(C) (12) 10
(D) (-812) 10
Ans: A
39. The circuit
converting binary data in to decimal is
(A) Encoder
(B) Multiplexer
(C) Decoder
(D) Code converter
Ans: D
40. A three input NOR
gate gives logic high output only when
(A) one input is high
(B) one input is low
(C) two input are low
(D) all input are high
Ans: D
41. n bits in operation
code imply that there are ___________ possible distinct operators
(A) 2n
(B) 2n
(C) n/2
(D) n2
Ans: B
42. _________ register
keeps tracks of the instructions stored in program stored in memory.
(A) AR (Address
Register)
(B) XR (Index Register)
(C) PC (Program Counter)
(D) AC (Accumulator)
Ans: C
43. Memory unit accessed
by content is called
(A) Read only memory
(B) Programmable Memory
(C) Virtual Memory
(D) Associative Memory
Ans: D
44. ‘Aging registers’
are
(A) Counters which
indicate how long ago their associated pages have been referenced.
(B) Registers which keep
track of when the program was last accessed.
(C) Counters to keep
track of last accessed instruction.
(D) Counters to keep
track of the latest data structures referred.
Ans: A
45 The instruction ‘ORG
O’ is a
(A) Machine Instruction.
(B) Pseudo instruction.
(C) High level
instruction.
(D) Memory instruction.
Ans: B
46 Translation from
symbolic program into Binary is done in
(A) Two passes.
(B) Directly
(C) Three passes.
(D) Four passes.
Ans: A
47 A floating point
number that has a O in the MSB of mantissa is said to have
(A) Overflow
(B) Underflow
(C) Important number
(D) Undefined
Ans: B
48 The BSA instruction
is
(A) Branch and store
accumulator
(B) Branch and save
return address
(C) Branch and shift
address
(D) Branch and show
accumulator
Ans: B
49 State whether True or
False.
(i) Arithmetic
operations with fixed point numbers take longer time for execution as compared
to with floating point numbers.
Ans: True.
(ii) An arithmetic shift
left multiplies a signed binary number by 2.
Ans: False.
