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Random technical questions and  their answers

The reason for documenting this topic is to provide important technical questions and answers on random topics related to computer networking, wireless networking, operating systems etc. These questions can appear in an aptitude test, organized by different recruiting IT organizations.


Important questions and their answers are as under:

A 2MB PCM (pulse code modulation) has
a) 32 channels
b) 30 voice channels & 1 signaling channel.
c) 31 voice channels & 1 signaling channel.
d) 32 channels out of which 30 voice channels, 1 signaling channel, & 1 Synchronization channel.

Ans. (c)


Time taken for 1 satellite hop in voice communication is
a) 1/2 second
b) 1 seconds
c) 4 seconds
d) 2 seconds

Ans. (a)


Max number of satellite hops allowed in voice communication is :
a) only one
b) more than one
c) two hops
d) four hops

Ans. (c)


What is the max. decimal number that can be accommodated in a byte.
a) 128
b) 256
c) 255
d) 512

Ans. (c)


Conditional results after execution of an instruction in a micro processor is stored in
a) register
b) accumulator
c) flag register
d) flag register part of PSW (Program Status Word)

Ans. (d)


Frequency at which VOICE is sampled is
a) 4 Khz
b) 8 Khz
c) 16 Khz
d) 64 Khz

Ans. (a)


Line of Sight is
a) Straight Line
b) Parabolic
c) Tx & Rx should be visible to each other
d) none

Ans. (c)


Purpose of PC (Program Counter) in a Micro-Processor is
a) To store address of TOS (Top Of Stack)
b) To store address of next instruction to be executed.
c) count the number of instructions.
d) to store base address of the stack.

Ans. (b)


What action is taken when the processor under execution is interrupted by a non-maskable interrupt?
a) Processor serves the interrupt request after completing the execution of the current instruction.
b) Processor serves the interrupt request after completing the current task.
c) Processor serves the interrupt request immediately.
d) Processor serving the interrupt request depends upon the priority of the current task under execution.

Ans. (a)


The status of the Kernel is
a) task
b) process
c) not defined.
d) none of the above.

Ans. (b)


To send a data packet using datagram, connection will be established
a) before data transmission.
b) connection is not established before data transmission.
c) no connection is required.
d) none of the above.

Ans. (c)

Word alignment is
a) aligning the address to the next word boundary of the machine.
b) aligning to even boundary.
c) aligning to word boundary.
d) none of the above.

Ans. (a)


When a 'C' function call is made, the order in which parameters passed to the function are pushed into the stack is
a) left to right
b) right to left
c) bigger variables are moved first than the smaller variables.
d) smaller variables are moved first than the bigger ones.
e) none of the above.

Ans. (b)


What is the type of signaling used between two exchanges?
a) inband
b) common channel signaling
c) any of the above
d) none of the above.

Ans. (a)


Buffering is
a) the process of temporarily storing the data to allow for small variation in device speeds
b) a method to reduce cross talks
c) storage of data within transmitting medium until the receiver is ready to receive.
d) a method to reduce routing overhead.

Ans. (a)

Memory allocation of variables declared in a program is
a) allocated in RAM.
b) allocated in ROM.
c) allocated on stack.
d) assigned to registers.

Ans. (c)

A software that allows a personal computer to pretend as a computer terminal is
a) terminal adapter
b) bulletin board
c) modem
d) terminal emulation

Ans. (d)


Which addressing mode is used in the following statements:

(a) MVI  B,55
(b) MOV B,A
(c) MOV M,A

Ans. (a) Immediate addressing mode.
(b) Register Addressing Mode
(c) Direct addressing mode

RS-232C standard is used in _____________.

Ans. Serial I/O

Memory. Management in Operating Systems is done by
a) Memory Management Unit
b) Memory management software of the Operating System
c) Kernel

Ans. (b)

What is done for a Push operation?

Ans. Stack Pointer is decremented and then the value is stored.

Binary equivalent of 52
Ans. 110100

Hexadecimal equivalent of 3452
Ans. 72A

Explain Just In Time Concept in one line ?
Ans. Elimination of waste by purchasing manufacturing exactly when needed

A good way of unit testing s/w program is
Ans. User test

OOT uses
Ans. Encapsulated of detect methods

What is Hard disk time for R/W head to move to correct sector called ?
Ans. Latency Time

The percentage of times a page number bound in associate register is called
Ans. Bit ratio

Expand MODEM
Ans. Modulator and Demodulator

RDBMS file system can be defined as
Ans. Interrelated

Super Key is
Ans. Primary key and Attribute.

In the scanf command of C language , h is used for
Ans. Short int

A process is defined as
Ans. Program in execution.

A thread is
Ans. Detachable unit of executable code.

What is meant by polymorphism ?
Ans. Redefinition of a base class method in a derived class.

What is the essential feature of inheritance ?
Ans. All properties of existing class are derived.

What does the protocol FTP do ?
Ans. Transfer a file b/w stations with user authentication

In the transport layer, TCP is what type of protocol
Ans. Connection oriented.

Why is a gateway used ?
Ans. To connect incompatible networks.

How is linked list implemented ?
Ans. By referential structures

What is a semaphore ?
Ans. It is a method for synchronization of multiple processes.

What is the precedence order from high to low ,of the symbols ( ) ++ /
Ans.( ) , ++, /

In which layer are routers used
Ans. In network layer

Which of the following sorting algorithm has average sorting behavior --
    Bubble sort, merge sort, heap sort, exchange sort

Ans. Heap sort

In binary search tree which traversal is used for getting ascending order values--Inorder ,post order, preorder
Ans. Inorder

What are device drivers used for ?
Ans. To provide software for enabling the hardware

What is fork command in Unix ?
Ans. System call used to create process

What is make command in Unix ?
Ans. Used for creation of more than one file.

In Unix .profile contains
Ans. Start up program

In Unix 'ls ' command stores contents in
Ans. inode block

Which of the following involves context switch,

(a) system call
(b) privileged instruction
(c) floating point exception
(d) all the above
(e) none of the above

Ans. (a)

In OSI, terminal emulation is done in

(a) sessions layer
(b) application layer
(c) presentation layer
(d) transport layer

Ans: (b)


For 1 MB memory, the  number of address lines required,

(d) 24

Ans. (b)


Semaphore is used for

(a) synchronization
(b) dead-lock avoidance
(c) box
(d) none

Ans. (a)


Piggy backing is a technique for

a) Flow control
b) Sequence
c) Acknowledgement
d) retransmission

Ans. (c)


Which is not a memory management scheme?

a) buddy system
b) swapping
c) monitors
d) paging

Ans. c


There was a circuit given using three nand gates with two inputs and one output.
    Find the output.

a) OR
b) AND
c) XOR
d) NOT

Ans. (a)


Integrated check value (ICV) are used as:

Ans. The client computes the ICV and then compares it with the senders value.


When applets are downloaded from web sites , a byte verifier performs _________?

Ans. Status check.


The UNIX shell ....

a) does not come with the rest of the system
b) forms the interface between the user and the kernel
c) does not give any scope for programming
d) does not allow calling one program from with in another
e) all of the above

Ans. (b)


In UNIX a files i-node ......?

Ans. Is a data structure that defines all specifications of a file like the file size, number of lines in the  file, permissions etc.


The very first process created by the kernel that runs till the kernel process is halts is

a) init
b) getty
c) both (a) and (b)
d) none of these

Ans. (a)


In the process table entry for the kernel process, the process id value is

(a) 0
(b) 1
(c) 2
(d) 255
(e) it does not have a process table entry

Ans. (a)

Which of the following API is used to hide a window

a) ShowWindow
b) EnableWindow
c) MoveWindow
d) SetWindowPlacement
e) None of the above

Ans. (a)


The redirection operators > and >>

a) do the same function
b) differ : > overwrites, while >> appends
c) differ : > is used for input while >> is used for output
d) differ : > write to any file while >> write only to standard output
e) None of these

Ans. (b)


The command grep first second third /usr/you/myfile

a) prints lines containing the words first, second or third from the file /usr/you/myfile
b) searches for lines containing the pattern first in the files
second, third, and /usr/you/myfile and prints them
c) searches the files /usr/you/myfiel and third for lines containing the words first or second and prints them
d) replaces the word first with the word second in the files third and /usr/you/myfile
e) None of the above

Ans. (b)

Which program construct must return a value?
a) Package
b) Function
c) Anonymous block
d) Stored Procedure
e) Application Procedure
Ans. (b)

Which three commands cause a transaction to end? (Choose three)

Ans. a ,b ,f


What was the first name given to Java Programming Language.
a) Oak - Java
b) Small Talk
c) Oak
d) None


When a bicycle is in motion, the force of friction exerted by the ground on the two wheels is such that it acts

(a) In the backward direction on the front wheel and in the forward direction on the rear wheel.
(b) In the forward direction on the front wheel and in the backward direction on the rear wheel.
(c) In the forward direction on both the front and rear wheels.
(d) In the backward direction on both the front and rear wheels.

Ans. (d)

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