Technical Interview Questions And Answers Pdf

1. What is a Network?
Answer: A network is a set of devices connected using a physical transmission medium.
Example: A Computer Network is a group of computers connected to communicate and share information and resources like hardware, data, and software across each other.

2. What are the concepts of Globalization and Localization in .NET?
Localization means “process of translating resources for a specific culture”, and Globalization means “process of designing applications that can adapt to different cultures”.

Proper Globalization: Your application should be able to Accept, Verify, and Display all global kind of data. It should well also be able to operate over this data, accordingly. We will discuss more this “Accordingly operations over the diff. culture data”.

Localizability and Localization: Localizability stands for clearly separating the components of culture-based operations regarding the user interface, and other operations from the executable code.
The .NET framework has greatly simplified the task of creating applications targeting the clients of multiple cultures
The namespaces involved in the creation of globalizing, localizing applications are:

  • System.Globalization
  • System.Resources
  • System.Text

3. How can we construct an increment statement or decrement statement in C?
We can do this in two different ways. 1) By using the increment operator ++ and decrement operator. For example, the statement “i++” means to increment the value of x by 1. Likewise, the statement “x –” means to decrement the value of x by 1. 2) The 2nd way of writing increment statements is to use the conventional + plus sign or minus sign. In the case of “i++, another way to write it is “i = I +1.

4. Explain the concept of Reentrancy?
It is a useful, memory-saving technique for multiprogrammed timesharing systems. A Reentrant Procedure is one in which multiple users can share a single copy of a program during the same period. Reentrancy has 2 key aspects: The program code cannot modify itself, and the local data for each user process must be stored separately. Thus, the permanent part is the code, and the temporary part is the pointer back to the calling program and local variables used by that program. Each execution instance is called activation. It executes the code in the permanent part but has its copy of local variables/parameters. The temporary part associated with each activation is the activation record. Generally, the activation record is kept on the stack.

Note: A reentrant procedure can be interrupted and called by an interrupting program, and still execute correctly on returning to the procedure.

5. What is the difference between verification and validation?
Verification is a review without actually executing the process while validation is checking the product with actual execution. For instance, code review and syntax check is verification while running the product and checking the results is validation.

6. So If Md5() Generates The Most Secure Hash, Why Would You Ever Use The Less Secure Crc32() And Sha1()?
Crypto usage in PHP is simple, but that doesn’t mean it’s free. First off, depending on the data that you’re encrypting, you might have reasons to store a 32-bit value in the database instead of the 160-bit value to save on space. Second, the more secure the crypto is, the longer is the computation time to deliver the hash value. A high volume site might be significantly slowed down if frequent md5() generation is required.

7. What is a Proxy Server and how do they protect the computer network?
For data transmission, IP addresses are required and even DNS uses IP addresses to route to the correct website. It means without the knowledge of correct and actual IP addresses it is not possible to identify the physical location of the network.

Proxy Servers prevent external users who are unauthorized to access such IP addresses of the internal network. The Proxy Server makes the computer network virtually invisible to the external users.

proxy server

image source: Proxy Server

Proxy Server also maintains the list of blacklisted websites so that the internal user is automatically prevented from getting easily infected by viruses, worms, etc. 

8. What is Data Encapsulation?
In a computer network, to enable data transmission from one computer to another, the network devices send messages in the form of packets. These packets are then added with the IP header by the OSI reference model layer.

The Data Link Layer encapsulates each packet in a frame that contains the hardware address of the source and the destination computer. If a destination computer is on the remote network then the frames are routed through a gateway or router to the destination computer. 

9. Define Network?
A network is a set of devices connected by physical media links. A network is recursively is a connection of two or more nodes by a physical link or two or more networks connected by one or more nodes.

10. What are the different types of joins in SQL?
There are 4 types of SQL Joins:

Inner Join: This type of join is used to fetch the data among the tables which are common in both the tables.
Left Join: This returns all the rows from the table which is on the left side of the join but only the matching rows from the table which is on the right side of the join.
Right, Join: This returns all the rows from the table which is on the right side of the join but only the matching rows from the table which is on the left side of the join.
Full Join: This returns the rows from all the tables on which the join condition has put and the rows which do not match hold null values.

11. What are the typical elements of a process image?
User data: Modifiable part of userspace. May include program data, user stack area, and programs that may be modified.

User program: The instructions to be executed.

System Stack: Each process has one or more LIFO stacks associated with it. Used to store parameters and calling addresses for procedure and system calls.

Process control Block (PCB): Info needed by the OS to control processes.

12. What are local and global page replacements?
Local replacement means that an incoming page is brought in only to the relevant process address space. A global replacement policy allows any page frame from any process to be replaced. The latter applies to the variable partitions model only.

Define latency, transfer and seek time concerning disk I/O.
Seek time is the time required to move the disk arm to the required track. Rotational delay or latency is the time it takes for the beginning of the required sector to reach the head. Sum of seek time (if any) and latency is the access time. Time taken to transfer a span of data is transfer time.
Describe the Buddy system of memory allocation.
Free memory is maintained in linked lists, each of equal-sized blocks. Any such block is of size 2^k. When some memory is required by a process, the block size of the next higher order is chosen, and broken into two. Note that the two such pieces differ in address only in their kth bit. Such pieces are called buddies. When any used block is freed, the OS checks to see if its buddy is also free. If so, it is rejoined, and put into the original free-block linked-list.

13. What is the Synchronous mode of data transmission?
It is a serial mode of transmission. In this mode of transmission, bits are sent in a continuous stream without start and stop bit and gaps between bytes. Regrouping the bits into meaningful bytes is the responsibility of the receiver.

14. What is the hamming code?
The hamming code is an error correction method using redundant bits. The number of bits is a function of the length of the data bits. In hamming code for a data unit of m bits, we use the formula 2r >= m+r+1 to determine the number of redundant bits needed. By rearranging the order of bit transmission of the data units, the hamming code can correct burst errors.

15. What is Hypertext Transfer Protocol(HTTP)?
It is the main protocol used to access data on the World Wide Web .the protocol transfers data in the form of plain text, hypertext, audio, video, and so on. It is so-called because its efficiency allows its use in a hypertext environment where there are rapid jumps from one document to another.

16. What is Beaconing?
The process that allows a network to self-repair network problems. The stations on the network notify the other stations on the ring when they are not receiving the transmissions. Beaconing is used in the Token ring and FDDI networks.

17. What is the difference between ARP and RARP?
The address resolution protocol (ARP) is used to associate the 32 bit IP address with the 48-bit physical address, used by a host or a router to find the physical address of another host on its network by sending an ARP query packet that includes the IP address of the receiver.

The reverse address resolution protocol (RARP) allows a host to discover its Internet address when it knows only its physical address.

18. What is the difference between baseband and broadband transmission?
In a baseband transmission, the entire bandwidth of the cable is consumed by a single signal. In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.

19. What Is Meant By Pear In Php?
PEAR is the next revolution in PHP. This repository is bringing higher level programming to PHP. PEAR is a framework and distribution system for reusable PHP components. It eases installation by bringing an automated wizard and packing the strength and experience of PHP users into a nicely organized OOP library. PEAR also provides a command-line interface that can be used to automatically install “packages”.

20. What Is A Persistent Cookie?
A persistent cookie is a cookie that is stored in a cookie file permanently on the browser’s computer. By default, cookies are created as temporary cookies which stored only in the browser’s memory. When the browser is closed, temporary cookies will be erased. You should decide when to use temporary cookies and when to use persistent cookies based on their differences:

  • Temporary cookies can not be used for tracking long-term information.
  • Persistent cookies can be used for tracking long-term information.
  • Temporary cookies are safer because no programs other than the browser can access them.
  • Persistent cookies are less secure because users can open cookie files to see the cookie values.

21. What Are The Differences Between getting And Post Methods In Form Submitting, Give The Case Where We Can Use Get And We Can Use Post Methods?
When you want to send short or small data, not containing ASCII characters, then you can use GET” Method. But for long data sending, say more than 100 characters you can use the POST method.

Once the most important difference is when you are sending the form with getting a method. You can see the output which you are sending in the address bar. Whereas if you send the form with the POST” method then the user can not see that information.

22. Explain DHCP briefly?
DHCP stands for Dynamic Host Configuration Protocol and it automatically assigns IP addresses to the network devices. It completely removes the process of manual allocation of IP addresses and reduces the errors caused due to this.

This entire process is centralized so that the TCP/IP configuration can also be completed from a central location. DHCP has a “pool of IP addresses” from which it allocates the IP address to the network devices. DHCP cannot recognize if any device is configured manually and assigned with the same IP address from the DHCP pool.

In this situation, it throws the “IP address conflict” error.


image source: DHCP

DHCP environment requires DHCP servers to set-up the TCP/IP configuration. These servers then assign, release and renew the IP addresses as there might be a chance that network devices can leave the network and some of them can join back to the network.

23. What sort of criteria are you using to decide the organization you will work for?
Most importantly, I am looking for a company that values quality, ethics, and teamwork. I would like
to work for a company that hires overachievers.

24. How would a professor who knows you well describe you? One who does not know you
A professor who knows me well would likely describe my personal qualities: sweet, down-to-earth,

smart, hard-working, and conscientious.
As specific examples of those who did not know me well, my soils professor and soils teaching
assistant each considered me smart and respectful, and both thought that I must have enjoyed the

25. What’s The Difference Between Htmlentities() And Htmlspecialchars()?
htmlspecialchars only take care of <, >, single quote ‘, double quote ” and ampersand.
htmlentities translates all occurrences of character sequences that have different meanings in HTML.

26. What is ASP.NET??
ASP.NET was developed in direct response to the problems that developers had with classic ASP. Since ASP is in such wide use, however, Microsoft ensured that ASP scripts execute without modification on a machine with the .NET Framework (the ASP engine, ASP.DLL, is not modified when installing the .NET Framework). Thus, IIS can house both ASP and ASP.NET scripts on the same machine. 

27. What is CMM?
The Capability Maturity Model for Software (CMM or SW-CMM) is a model for judging the maturity of the software processes of an organization and for identifying the key practices that are required to increase the maturity of these processes.

28. What is .Net framework?
It is a platform for building various applications on windows. It has a list of inbuilt functionalities in the form of class, library, and APIs which are used to build, deploy and run web services and different applications. It supports different languages such as C#, VB .Net, Cobol, Perl, etc.

29. In the C program, how we can insert quote characters (‘ and ”) into the output screen?
This is a common problem for freshers/beginners because quotes are normally part of a “printf” statement in the program. If we want to insert the quote character as part of the output, use the format specifiers, and ” (for a double quote),’ (for a single quote)

30. What are Firewalls?
It is an electronic downbridge which is used to enhance the security of a network. Its configuration has two components.

i)Two routers
ii)Application gateway
the packets traveling through the LAN are inspected here and packets meeting certain criteria are forwarded and others are dropped.

31. What is time-stamping?
It is a technique proposed by Lamport, used to order events in a distributed system without the use of clocks. This scheme is intended to order events consisting of the transmission of messages. Each system ‘i’ in the network maintains a counter Ci. Every time a system transmits a message, it increments its counter by 1 and attaches the time-stamp Ti to the message. When a message is received, the receiving system ‘j’ sets its counter Cj to 1 more than the maximum of its current value and the incoming time-stamp Ti. At each site, the ordering of messages is determined by the following rules: For messages x from a site i and y from site j, x precedes y if one of the following conditions holds….(a) if Ti<j.

32. What is busy waiting for?
The repeated execution of a loop of code while waiting for an event to occur is called busy-waiting. The CPU is not engaged in any real productive activity during this period, and the process does not progress toward completion.

Explain the popular multiprocessor thread-scheduling strategies.
Load Sharing: Processes are not assigned to a particular processor. A global queue of threads is maintained. Each processor, when idle, selects a thread from this queue. Note that load balancing refers to a scheme where work is allocated to processors on a more permanent basis.
Gang Scheduling: A set of related threads is scheduled to run on a set of processors at the same time, on a 1-to-1 basis. Closely related threads/processes may be scheduled this way to reduce synchronization blocking, and minimize process switching. Group scheduling predated this strategy.
Dedicated processor assignment: Provides implicit scheduling defined by the assignment of threads to processors. For the duration of program execution, each program is allocated a set of processors equal in number to the number of threads in the program. Processors are chosen from the available pool.
Dynamic scheduling: The number of threads in a program can be altered during execution.

33. What are the different types of multiplexing?
Multiplexing is of three types. Frequency division multiplexing and wave division multiplexing are for analog signals and time division multiplexing is for digital signals.

34. What is the World Wide Web?
Answer: The 
World Wide Web is a repository of information spread all over the world and linked together. It is a unique combination of flexibility, portability, and user-friendly features. The World Wide Web today is a distributed client-server service, in which a client using a browser can access a service using a server. The service provided is distributed over many locations called web sites.

35. What is the difference between baseband and broadband transmission?
In a baseband transmission, the entire bandwidth of the cable is consumed by a single signal. In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.

36. What is Hypertext Transfer Protocol(HTTP)?
It is the main protocol used to access data on the World Wide Web .the protocol transfers data in the form of plain text, hypertext, audio, video, and so on. It is so-called because its efficiency allows its use in a hypertext environment where there are rapid jumps from one document to another.

37. Describe the layers of the OSI model?
OSI model stands for Open System Interconnection It is a framework that guides the applications on how they can communicate in a network.

OSI model has seven layers. They are listed below,

Physical Layer (Deals with transmission and reception of unstructured data through a physical medium)
Data Link Layer (Helps in transferring error-free data frames between nodes)
Network Layer (Decides the physical path that should be taken by the data as per the network conditions)
Transport Layer (Ensures that the messages are delivered in sequence and without any loss or duplication)
Session Layer (Helps in establishing a session between processes of different stations)
Presentation Layer (Formats the data as per the need and presents the same to Application layer)
Application Layer (Serves as the mediator between Users and processes of applications).

38. Explain the characteristics of networking?
The main characteristics of networking are mentioned below,

Topology: This deals with how the computers or nodes are arranged in the network. The computers are arranged physically or logically.
Protocols: Deals with the process of how computers communicate with one another.
Medium: This is nothing but the medium used by computers for communication.

39. In how many ways the data is represented and what are they?
Data transmitted through the networks’ comes in different ways like text, audio, video, images, numbers, etc.

Audio: It is nothing but the continuous sound which is different from text and numbers.
Video: Continuous visual images or a combination of images.
Images: Every image is divided into pixels. And the pixels are represented using bits. Pixels may vary in size based on image resolution.
Numbers: These are converted into binary numbers and are represented using bits.
Text: Text is also represented as bits.

40. What is MVC?
MVC stands for Model View Controller. It is an architectural model for building the .Net applications.

Models – Model objects store and retrieve data from the database for an application. They are usually the logical parts of an application that is implemented by the application’s data domain.

View – These are the components that display the view of the application in the form of UI. The view gets the information from the model objects for their display. They have components like buttons, drop boxes, combo boxes, etc.

Controllers – They handle the User Interactions. They are responsible for responding to the user inputs, work with the model objects, and pick a view to be rendered to the user.

41. What is ICMP?
ICMP is an Internet Control Message Protocol, a network layer protocol of the TCP/IP suite used by hosts and gateways to send notification of datagram problems back to the sender. It uses the echo test/reply to test whether a destination is reachable and responding. It also handles both control and error messages.

42. What is the IP address?
The internet address (IP address) is 32bits that uniquely and universally defines a host or router on the internet. The portion of the IP address that identifies the network is called netid. The portion of the IP address that identifies the host or router on the network is called hosting.

43. Explain CAS (Code Access Security)?
Net provides a security model that prevents unauthorized access to resources. CAS is a part of that security model. CAS is present in the CLR. It enables the users to set permissions at a granular level for the code.

CLR then executes the code depending on the available permissions. CAS can be applied only to the managed code. Unmanaged code runs without CAS. If CAS is used on assemblies, then the assembly is treated as partially trusted. Such assemblies must undergo checks whenever it tries to access a resource.

The different components of CAS are Code group, Permissions, and Evidence.

Evidence– To decide what permissions to give, the CAS and CLR depend on the specified evidence by the assembly. The examination of the assembly provides details about the different pieces of evidence. Some common evidence includes Zone, URL, Site, Hash Value, Publisher and Application directory.

Code Group – Depending on the evidence, codes are put into different groups. Each group has specific conditions attached to it. Any assembly that matches those conditions is put into that group.

Permissions – Each code group can perform only specific actions. They are called Permissions. When CLR loads an assembly, it matches them to one of the code groups and identifies what actions those assemblies can do. Some of the Permissions include Full Trust, Everything, Nothing, Execution, Skip Verification, and the Internet.

44. What is Network Topology?
Network Topology is a physical layout of the computer network and it defines how the computers, devices, cables, etc are connected.

45. What are Routers?
The router is a network device that connects two or more network segments. The router is used to transfer information from the source to the destination.

Routers send the information in terms of data packets and when these data packets are forwarded from one router to another router then the router reads the network address in the packets and identifies the destination network.

46. What is DNS?
Domain Name Server (DNS), in a non-professional language and we can call it as the Internet’s phone book. All the public IP addresses and their hostnames are stored in the DNS and later it translates into a corresponding IP address.

For a human being, it is easy to remember and recognize the domain name, however, the computer is a machine that does not understand the human language and they only understand the language of IP addresses for data transfer.

There is a “Central Registry” where all the domain names are stored and it gets updated periodically. All the internet service providers and different host companies usually interact with this central registry to get the updated DNS details.

For Example: When you type a website , then your internet service provider looks for the DNS associated with this domain name and translates this website command into a machine language – IP address – (note that, this is imaginary IP address and not the actual IP for the given website) so that you will get redirected to the appropriate destination.

This is shortly explained in the below diagram:


image source: DNS

47. what are config and ifconfig?
Ipconfig stands for Internet Protocol Configuration and this command is used on Microsoft Windows to view and configure the network interface.

The command ipconfig is useful for displaying all TCP/IP network summary information currently available on a network. It also helps to modify the DHCP protocol and DNS setting.

Ifconfig (Interface Configuration) is a command that is used on Linux, Mac, and UNIX operating systems. It is used to configure, control the TCP/IP network interface parameters from CLI i.e. Command Line Interface. It allows you to see the IP addresses of these network interfaces

48. What is the Asynchronous mode of data transmission?
It is a serial mode of transmission.

In this mode of transmission, each byte is framed with a start bit and a stop bit. There may be a variable-length gap between each byte.

49. What are the different types of networks? Explain each briefly?
There are 4 major types of networks.

Let’s take a look at each of them in detail.

Personal Area Network (PAN): It is the smallest and basic network type that is often used at home. It is a connection between the computer and another device such as phone, printer, modem tablets, etc
Local Area Network (LAN): LAN is used in small offices and internet cafes to connect a small group of computers. Usually, they are used to transfer a file or for playing the game in a network.
Metropolitan Area Network (MAN): It is a powerful network type than LAN. The area covered by MAN is a small town, city, etc. A huge server is used to cover such a large span of area for connection.
Wide Area Network (WAN): It is more complex than LAN and covers a large span of the area typically a large physical distance. The Internet is the largest WAN which is spread across the world. WAN is not owned by any single organization but it has distributed ownership.
There are some other types of the network as well:

  • Storage Area Network (SAN)
  • System Area Network (SAN)
  • Enterprise Private Network (EPN)
  • Passive Optical Local Area Network (POLAN)

50. What is call by value and call by reference in C Programming language?
We can pass a value to function in two different ways: call by value and call by reference. In case of call by value, a copy of the value is passed to the function, so the original value is not modified in the call by value. But in case of call by reference, an address of value is passed to the function, so the original value is modified in the call by reference.

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