C# Interview Questions and Answers PDF Download

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C# Interview Questions
C# interview questions and answers most asked at top companies. These C# questions are for both experienced & fresher candidates PDF Download Free.

List of C# Interview Questions and Answers PDF

What is C#?

C# is an object oriented, type safe and managed language that is compiled by .Net framework to generate Microsoft Intermediate Language.

What are the types of comment in C# with examples?

Single line

Eg: //This is a Single line comment

 

ii. Multiple line (/* */)

/*This is a multiple line comment
We are in line 2
Last line of comment*/

 

iii. XML Comments (///).

/// summary;
///  Set error message for multilingual language.
/// summary

Can multiple catch blocks be executed?

No, Multiple catch blocks can’t be executed. Once the proper catch code executed, the control is transferred to the finally block and then the code that follows the finally block gets executed.

What is the difference between public, static and void?

Public declared variables or methods are accessible anywhere in the application. Static declared variables or methods are globally accessible without creating an instance of the class. Static member are by default not globally accessible it depends upon the type of access modified used. The compiler stores the address of the method as the entry point and uses this information to begin execution before any objects are created. And Void is a type modifier that states that the method or variable does not return any value.

What is an object?

An object is an instance of a class through which we access the methods of that class. “New” keyword is used to create an object. A class that creates an object in memory will contain the information about the methods, variables and behavior of that class.

Define Constructors?

A constructor is a member function in a class that has the same name as its class. The constructor is automatically invoked whenever an object class is created. It constructs the values of data members while initializing the class.

What is Jagged Arrays?

The array which has elements of type array is called jagged array. The elements can be of different dimensions and sizes. We can also call jagged array as Array of arrays.

What is the difference between ref & out parameters?

An argument passed as ref must be initialized before passing to the method whereas out parameter needs not to be initialized before passing to a method.

What is the use of using statement in C#?

The using block is used to obtain a resource and use it and then automatically dispose of when the execution of block completed.

What is serialization?

When we want to transport an object through network then we have to convert the object into a stream of bytes. The process of converting an object into a stream of bytes is called Serialization. For an object to be serializable, it should implement ISerialize Interface. De-serialization is the reverse process of creating an object from a stream of bytes.

Can “this” be used within a static method?

We can’t use ‘This’ in a static method because we can only use static variables/methods in a static method.

What is difference between constants and read-only?

Constant variables are declared and initialized at compile time. The value can’t be changed afterwards. Read only is used only when we want to assign the value at run time.

What is an interface class?

Interface is an abstract class which has only public abstract methods and the methods only have the declaration and not the definition. These abstract methods must be implemented in the inherited classes.

What are value types and reference types?

Value types are stored in the Stack whereas reference types stored on heap.
Value types:

int, enum , byte, decimal, double, float, long

 

Reference Types:

string , class, interface, object

What are Custom Control and User Control?

Custom Controls are controls generated as compiled code (Dlls), those are easier to use and can be added to toolbox. Developers can drag and drop controls to their web forms. Attributes can be set at design time. We can easily add custom controls to Multiple Applications (If Shared Dlls), If they are private then we can copy to dll to bin directory of web application and then add reference and can use them.
User Controls are very much similar to ASP include files, and are easy to create. User controls can’t be placed in the toolbox and dragged – dropped from it. They have their design and code behind. The file extension for user controls is ascx.

What are sealed classes in C#?

We create sealed classes when we want to restrict the class to be inherited. Sealed modifier used to prevent derivation from a class. If we forcefully specify a sealed class as base class then a compile-time error occurs.

What are the differences between System.String and System.Text.StringBuilder classes?

System.String is immutable. When we modify the value of a string variable then a new memory is allocated to the new value and the previous memory allocation released. System.StringBuilder was designed to have concept of a mutable string where a variety of operations can be performed without allocation separate memory location for the modified string.

What is method overloading?

Method overloading is creating multiple methods with the same name with unique signatures in the same class. When we compile, the compiler uses overload resolution to determine the specific method to be invoke

What’s the difference between the System.Array.CopyTo() and System.Array.Clone() ?

Using Clone() method, we creates a new array object containing all the elements in the original array and using CopyTo() method, all the elements of existing array copies into another existing array. Both the methods perform a shallow copy

What is the difference between Array and Arraylist?

In an array, we can have items of the same type only. The size of the array is fixed. An arraylist is similar to an array but it doesn’t have a fixed size.

Can a private virtual method be overridden?

No, because they are not accessible outside the class.

Describe the accessibility modifier “protected internal”.

Protected Internal variables/methods are accessible within the same assembly and also from the classes that are derived from this parent class.

How can we sort the elements of the array in descending order?

Using Sort() methods followed by Reverse() method.

Write down the C# syntax to catch exception?

To catch an exception, we use try catch blocks. Catch block can have parameter of system.Exception type.

Eg:

try
{
GetAllData();
}
catch(Exception ex)
{
}

What’s the difference between an interface and abstract class?

Interfaces have all the methods having only declaration but no definition. In an abstract class, we can have some concrete methods. In an interface class, all the methods are public. An abstract class may have private methods.

What is the difference between Finalize() and Dispose() methods?

Dispose() is called when we want for an object to release any unmanaged resources with them. On the other hand Finalize() is used for the same purpose but it doesn’t assure the garbage collection of an object

What are circular references?

Circular reference is situation in which two or more resources are interdependent on each other causes the lock condition and make the resources unusable.

What are generics in C#.NET?

Generics are used to make reusable code classes to decrease the code redundancy, increase type safety and performance. Using generics, we can create collection classes. To create generic collection, System.Collections.Generic namespace should be used instead of classes such as ArrayList in the System.Collections namespace. Generics promotes the usage of parameterized types.

What is an object pool in .NET?

An object pool is a container having objects ready to be used. It tracks the object that is currently in use, total number of objects in the pool. This reduces the overhead of creating and re-creating objects.

List down the commonly used types of exceptions in .Net?

ArgumentException, ArgumentNullException , ArgumentOutOfRangeException, ArithmeticException, DivideByZeroException ,OverflowException , IndexOutOfRangeException ,InvalidCastException ,InvalidOperationException , IOEndOfStreamException , NullReferenceException , OutOfMemoryException , StackOverflowException etc.

What are Custom Exceptions?

Sometimes there are some errors that need to be handeled as per user requirements. Custom exceptions are used for them and are used defined exceptions.

What are delegates?

Delegates are same are function pointers in C++ but the only difference is that they are type safe unlike function pointers. Delegates are required because they can be used to write much more generic type safe functions.

How do you inherit a class into other class in C#?

Colon is used as inheritance operator in C#. Just place a colon and then the class name.

public class DerivedClass : BaseClass

What is the base class in .net from which all the classes are derived from?

System.Object

What is the difference between method overriding and method overloading?

In method overriding, we change the method definition in the derived class that changes the method behavior. Method overloading is creating a method with the same name within the same class having different signatures.

What are the different ways a method can be overloaded?

Methods can be overloaded using different data types for parameter, different order of parameters, and different number of parameters.

Why can’t you specify the accessibility modifier for methods inside the interface?

In an interface, we have virtual methods that do not have method definition. All the methods are there to be overridden in the derived class. That’s why they all are public.

How can we set class to be inherited, but prevent the method from being over-ridden?

Declare the class as public and make the method sealed to prevent it from being overridden.

What happens if the inherited interfaces have conflicting method names?

Implement is up to you as the method is inside your own class. There might be problem when the methods from different interfaces expect different data, but as far as compiler cares you’re okay.

What is the difference between a Struct and a Class?

Structs are value-type variables and classes are reference types. Structs stored on the stack, causes additional overhead but faster retrieval. Structs cannot be inherited.

How to use nullable types in .Net?

Value types can take either their normal values or a null value. Such types are called nullable types.

Int? someID = null;
If(someID.HasVAlue)
{
}

How we can create an array with non-default values?

We can create an array with non-default values using Enumerable.Repeat.

What is difference between is and as operators in c#?

“is” operator is used to check the compatibility of an object with a given type and it returns the result as Boolean.

“as” operator is used for casting of object to a type or a class.

What’s a multicast delegate?

A delegate having multiple handlers assigned to it is called multicast delegate. Each handler is assigned to a method.

What are indexers in C# .NET?

Indexers are known as smart arrays in C#. It allows the instances of a class to be indexed in the same way as array.

Eg:

public int this[int index]    // Indexer declaration

What is difference between the “throw” and “throw ex” in .NET?

“Throw” statement preserves original error stack whereas “throw ex” have the stack trace from their throw point. It is always advised to use “throw” because it provides more accurate error information.

What are C# attributes and its significance?

C# provides developers a way to define declarative tags on certain entities eg. Class, method etc. are called attributes. The attribute’s information can be retrieved at runtime using Reflection.

How to implement singleton design pattern in C#?

In singleton pattern, a class can only have one instance and provides access point to it globally.

Eg:

Public sealed class Singleton
{
Private static readonly Singleton _instance = new Singleton();
}

What is the difference between directcast and ctype?

DirectCast is used to convert the type of an object that requires the run-time type to be the same as the specified type in DirectCast.

Ctype is used for conversion where the conversion is defined between the expression and the type.

Is C# code is managed or unmanaged code?

C# is managed code because Common language runtime can compile C# code to Intermediate language.

BPO Interview Questions and Answers PDF Download

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BPO Interview Questions
BPO interview questions and answers most asked at top companies. These BPO questions are for both experienced & fresher candidates PDF Download Free.

List of BPO Interview Questions and Answers PDF

Tell me something about BPO and how it works?

BPO is abbreviated as Business Process Outsourcing.  When a company wants its non-core work to be done by an expert at cheaper costs then they outsource their work to other country, which is called Business Process Outsourcing.  The outsourcing is generally made between two countries.

What are the major sectors for outsourcing?

IT and Communication, Medical and health services, Insurance, Finance, Law and Jurisdiction are some of the sectors where majority of outsourcing works get done.

Are you comfortable working in night shifts?

Always answer this question as yes, as the majority of the outsourcing work is done according to the country timeline from where the work gets outsourced in which case it is night shift most of the time.  It also shows your willingness and interest towards the roles and your approach towards the job.

What is the difference between the shore and off-shore outsourcing?

When any project or work allotted outside the country which is not nearby is called off-shore outsourcing and anything outsourced nearby country is called shore outsourcing.

What is inbound and outbound call centers?

An inbound call centers will only receive calls while outbound call centers will place calls. In general inbound call centers function as companies service department, while outbound handles the service department.

Which one do you think –web or voice- suits your qualifications better?

Since, they are asking you for your preference there is no problem in telling your choice. Just have to make sure that whatever option you chose had a legitimate reason.

How can you relate call centers to BPO?

Call centers may be one of the very first processes in a business that was openly outsourced.

What is the difference between KPO and BPO?

KPO is a knowledge process outsourcing while BPO is business process outsourcing.  KPO provides the knowledge based services like medical billing, documentation or claiming insurance. While BPO is totally customer service oriented.

What are the different types of BPO’s?

BPOs are segmented into five different categories.

  • Administrative Department
  • Purchase Department
  • Selling Department
  • Call Centre
  • Back Office
Why companies Outsource?
  • It is cost saving
  • To focus on core activities
  • To get quality work done by the expertise in that domain
Why do you see BPO as your career?

BPO has always been a career choice for me as you are exposed to a new field, which gives you an opportunity to grow and develop your personality and communication skills.  The recent survey also tells the fast growth of this industry.

Why do you think you will do well in this job?

Give several reasons like experience, interest and skills.

What is a call centre?

Call center is a customer care center where calls are handled in large numbers.  There are two types of call centers, Inbound and Outbound.  An inbound call center is where calls are handled keeping the customer care in concern, and customer associate will only receive calls. While in outbound call center the calls are done by the associate for product inquires or sometimes sales related.

Where you see BPO in the current market?

In the current situation where many companies failed to survive in the market, BPO sector has achieved a milestone in an economic crisis. It helped to reduce the unemployment rate marginally in developing countries where some of the developed countries even failed to do that.

Can you use different software’s easily?

When you answer this question clarifies interviewer about your computer knowledge and your grip over software, so that they have a clear idea what training you might need further if you get selected.

Why do you want to work for our company?

This question is put in front of you by the interviewer to analyse how much you are aware of the companies work and how keen you are with the company projects.  When you answer this question, mention about the company’s creative business policies, aggressive market stance and the growth of the company.

Determine the type of BPO you wish to work?

Generally, they want to know your area of interest. Whether you like to work in a research driven or a voice based process.  There are many branches where BPO operates it could be a KPO (Knowledge process outsourcing) or even RPO (Research process outsourcing). So according the to the company’s requirement you can answer to it.

How good are you with computer skills?

Most of the time they usually ask for basic computer skills, but if the job demands more computer work then they will hold a practical test to check your computer skills.

Do you think that the career opportunity for non-voice BPO is better than voice BPO?

In both types of BPO,the opportunities are same, but it depends more on an individual’s interest and its personality.  Once you gain expertise in the work, you can easily head up towards management or support side.

Will you be comfortable handling customers on the phone?

If you are a fresher you can tell that handling customer on the phone would be a challenge but you would be able to handle it and won’t disappoint the company as well as the customer.

Do you know the common risk associated with BPO’s and how will you cope with them?

BPO’s have a huge data of customer’s personal information.  Any breach in the security system will lead to leakage of customer’s information, which can spoil the company’s reputation if it is used for some wrong purpose.  To avoid such risk, employee or associate must not allow to carry any external hard drive or flash drive with them while they on board. The de-activation of login-in ids of ex-employee must be done on the immediate basis, so that they cannot misuse them to retrieve customers information from anywhere.  You can also install additional security software to secure the main server from getting hacked.

Did you learn anything new recently which can be helpful to BPO’s?

Knowing additional language apart from English is always beneficial in BPO’s . You can learn any other foreign language such as French or Spanish; it always give you more chances of securing jobs in BPO’s.

What is ISO:9000 in outsourcing?

In  an outsourcing, ISO:9000 is a standard of mapping quality for the company.  Most of the BPO companies have accepted ISO:9000 as the benchmark for the quality of service they offer.

What are the job activities you have to maintain in BPO?

The main activity in a call center is to handle the customers queries effectively and satisfactory. Also to co-ordinate well in a team in order to offer the best service possible to the customer.

Where do you see yourself after five years?

The perfect answer for this question should be like “ In five years from now I want to see myself at responsible position where my company see me as valuable assets and at the same time to grow with the company”.

Nginx Interview Questions and Answers PDF Download

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Nginx Interview Questions
Nginx interview questions and answers most asked at top companies. These Nginx questions are for both experienced & fresher candidates PDF Download Free.

List of Nginx Interview Questions and Answers PDF

What is Nginx?

Nginx is a web server and a reverse proxy server for HTTP, HTTPS, SMTP, POP3 and IMAP protocols.

Mention some special features of Nginx?

Special features of the Nginx server includes

  • Reverse proxy/ L7 Load Balancer
  • Embedded Perl interpreter
  • On the fly binary upgrade
  • Useful for re-writing URLs and awesome PCRE support
What is the difference between Nginx and Apache?
                      Nginx                                  Apache
  • Nginx is an event based web server
  • All request are handled by a single thread.
  • Nginx avoids child processes idea.
  • Nginx resembles speed
  • Nginx is better when it comes to memory consumption and connection
  • Nginx is better when you want load-balancing
  • For PHP, Nginx might be preferable as it supports PHP internally
  • Nginx do not support O.S like IBMi and OpenVMS.
  • Nginx comes only with core features
  • Nginx performance and scalability do not depend on hardware
  •  Apache is a process based server
  • Single thread handles a single request.
  • Apache is based on child processes
  • Apache resemble power
  • Apache is not up-to the mark when it comes to memory consumption and connection
  • Apache will refuse new connections when traffic reaches the limit of processes
  • Apache support’s PHP, Python, Perl and other languages using plugins. It is useful when application is based on Python or Ruby
  • Apache support much wider range of O.S
  • Apache provides lot more functionality than Nginx
  • Apache is dependent on hardware components like CPU and memory
How Nginx can handle HTTP requests?

Nginx uses the reactor pattern.  The main event loop waits for the OS to signal a readiness event- such that the data is accessible to read from a socket, at which instance it is read into the buffer and processed.  A Single thread can serve tens of thousands of simultaneous connections.

In Nginx how you can prevent processing requests with undefined server names?

A server that just drops the requests can be defined as

 

Server {

listen                80;

server_name  “ “ ;

return              444;

}

Here the server name is kept as an empty string which will match request without the “Host” header field, and a special Nginx’s non-standard code 444 is returned that terminates the connection.

What is the advantage of using a “reverse proxy server”?

The reverse proxy server can hide the presence and characteristics of the origin server. It acts as an intermediate between internet cloud and web server. It is good for security reason especially when you are using web hosting services.

What is the best usage of Nginx server?

The best usage of Nginx server is to deploy dynamic HTTP content on a network with using SCGI, WSGI application servers, FastCGI handlers for scripts.  It can also serve as a load balancer.

What is the Master and Worker Processes in Nginx Server?
  • Master processes: It reads as well as evaluates configuration and maintains worker processes.
  • Worker processes: It actually does the processing of the requests.
How you can start Nginx through a different port other than 80?

To start Nginx through a different port, you have to go to /etc/Nginx/sites-enabled/ and if this is the default file, then you have to open file called “default.” Edit the file and put the port you want

Like server { listen 81; }

Is it possible to replace Nginx errors like 502 error with 503?
  • 502= Bad gateway
  • 503= Server overloaded

Yes, it is possible but you to ensure that fastcgi_intercept_errors is set to ON, and use the error page directive.

 

Location / {

fastcgi_pass 127.0.01:9001;

fastcgi_intercept_errors on;

error_page 502 =503/error_page.html;

#…

}

In Nginx, How you can keep double slashes in URLs?

To keep double slashes in URLs you have to use merge_slashes_off;

Syntax: merge_slashes [on/off]

Default: merge_slashes on

Context: http, server

What is ngx_http_upstream_module is used for?

The ngx_http_upstream_module is used to define groups of servers that can reference by the fastcgi pass, proxy pass, uwsgi pass, memcached pass and scgi pass directives.

What is C10K problem?

C10K problem is referred for the network socket unable to handle a large number of client (10,000) at the same time.

What is the use of stub_status and sub_filter directives?
  • Stub_status directive: This directive is used to know the current status of Nginx like current active connection, total connection accepted and handled current number of read/write/wait connection
  • Sub_filter directive: It is used to search and replace the content in response, and quick fix for stale data
Does Nginx support compress the request to the upstream?

You can compress the request to the upstream by using the Nginx modulegunzip. The gunzip module is a filter that decompresses responses with “Content Encoding: gzip” for clients or servers that do not support “gzip” encoding method.

How you can get the current time in Nginx?

To get the current time in Nginx, you have to use variables from SSI module, $date_gmt and $date_local.

  • Proxy_set_header THE-TIME $date_gmt;
What is the purpose of –s with Nginx Server?

To run the executable file of Nginx –s parameter is used.

How to add modules in Nginx Server?

During the compilation process, Nginx modules must be selected as such run-time selection of modules is not supported by Nginx.

Networking Interview Questions and Answers PDF Download

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Networking Interview Questions
Networking interview questions and answers most asked at top companies. These Networking questions are for both experienced & fresher candidates PDF Download Free.

List of Networking Interview Questions and Answers PDF

What is the job of the Network Layer under the OSI reference model?

The Network layer is responsible for data routing, packet switching and control of network congestion. Routers operate under this layer.

What is the difference between CSMA/CD and CSMA/CA?

CSMA/CD, or Collision Detect, retransmits data frames whenever a collision occurred. CSMA/CA, or Collision Avoidance, will first broadcast intent to send prior to data transmission.

What is NOS?

NOS, or Network Operating System, is specialized software whose main task is to provide network connectivity to a computer in order for it to be able to communicate with other computers and connected devices.

What is sneakernet?

Sneakernet is believed to be the earliest form of networking wherein data is physically transported using removable media, such as disk, tapes.

What is SLIP?

SLIP, or Serial Line Interface Protocol, is actually an old protocol developed during the early UNIX days. This is one of the protocols that are used for remote access.

One way of securing a network is through the use of passwords. What can be considered as good passwords?

Good passwords are made up of not just letters, but by combining letters and numbers. A password that combines uppercase and lowercase letters is favorable than one that uses all upper case or all lower case letters. Passwords must be not words that can easily be guessed by hackers, such as dates, names, favorites, etc. Longer passwords are also better than short ones.

What are the layers of the OSI reference model?

There are 7 OSI layers: Physical Layer, Data Link Layer, Network Layer, Transport Layer, Session Layer, Presentation Layer and Application Layer.

What are the maximum networks and hosts in a class A, B and C network?

For Class A, there are 126 possible networks and 16,777,214 hosts

For Class B, there are 16,384 possible networks and 65,534 hosts


For Class C, there are 2,097,152 possible networks and 254 hosts

What is the proper termination rate for UTP cables?

The proper termination for unshielded twisted pair network cable is 100 ohms.

What is backbone network?

A backbone network is a centralized infrastructure that is designed to distribute different routes and data to various networks. It also handles management of bandwidth and various channels.

What is the standard color sequence of a straight-through cable?

orange/white, orange, green/white, blue, blue/white, green, brown/white, brown.

How does a network topology affect your decision in setting up a network?

Network topology dictates what media you must use to interconnect devices. It also serves as basis on what materials, connector and terminations that is applicable for the setup.

What is SMTP?

SMTP is short for Simple Mail Transfer Protocol. This protocol deals with all Internal mail, and provides the necessary mail delivery services on the TCP/IP protocol stack.

What is DoS?

DoS, or Denial-of-Service attack, is an attempt to prevent users from being able to access the internet or any other network services. Such attacks may come in different forms and are done by a group of perpetuators. One common method of doing this is to overload the system server so it cannot anymore process legitimate traffic and will be forced to reset.

What is the role of IEEE in computer networking?

IEEE, or the Institute of Electrical and Electronics Engineers, is an organization composed of engineers that issues and manages standards for electrical and electronic devices. This includes networking devices, network interfaces, cablings and connectors.

Give some examples of private network addresses.

10.0.0.0 with a subnet mask of 255.0.0.0

172.16.0.0 with subnet mask of 255.240.0.0


192.168.0.0 with subnet mask of 255.255.0.0

What is netstat?

Netstat is a command line utility program. It provides useful information about the current TCP/IP settings of a connection.

What is a LAN?

LAN is short for Local Area Network. It refers to the connection between computers and other network devices that are located within a small physical location.

What protocols fall under the Application layer of the TCP/IP stack?

The following are the protocols under TCP/IP Application layer: FTP, TFTP, Telnet and SMTP.

What is RIP?

RIP, short for Routing Information Protocol is used by routers to send data from one network to another. It efficiently manages routing data by broadcasting its routing table to all other routers within the network. It determines the network distance in units of hops.

What is multicast routing?

Multicast routing is a targeted form of broadcasting that sends message to a selected group of user, instead of sending it to all users on a subnet.

What is OSI and what role does it play in computer networks?

OSI (Open Systems Interconnect) serves as a reference model for data communication. It is made up of 7 layers, with each layer defining a particular aspect on how network devices connect and communicate with one another. One layer may deal with the physical media used, while another layer dictates how data is actually transmitted across the network.

What protocols fall under the TCP/IP Internet Layer?

There are 4 protocols that are being managed by this layer. These are ICMP, IGMP, IP and ARP.

What is tracert?

Tracert is a Windows utility program that can used to trace the route taken by data from the router to the destination network. It also shows the number of hops taken during the entire transmission route.

What is the number of network IDs in a Class C network?

For a Class C network, the number of usable Network ID bits is 21. The number of possible network IDs is 2 raised to 21 or 2,097,152. The number of host IDs per network ID is 2 raised to 8 minus 2, or 254.

What is a node?

A node refers to a point or joint where a connection takes place. It can be computer or device that is part of a network. Two or more nodes are needed in order to form a network connection.

You need to connect two computers for file sharing. Is it possible to do this without using a hub or router?

Yes, you can connect two computers together using only one cable. A crossover type cable can be use in this scenario. In this setup, the data transmit pin of one cable is connected to the data receive pin of the other cable, and vice versa.

What are different ways of securing a computer network?

There are several ways to do this. Install reliable and updated anti-virus program on all computers. Make sure firewalls are setup and configured properly. User authentication will also help a lot. All of these combined would make a highly secured network.

What is the importance of Encryption on a network?

Encryption is the process of translating information into a code that is unreadable by the user. It is then translated back or decrypted back to its normal readable format using a secret key or password. Encryption help ensure that information that is intercepted halfway would remain unreadable because the user has to have the correct password or key for it.

What is the purpose of cables being shielded and having twisted pairs?

The main purpose of this is to prevent crosstalk. Crosstalks are electromagnetic interferences or noise that can affect data being transmitted across cables.

When it comes to networking, what are rights?

Rights refer to the authorized permission to perform specific actions on the network. Each user on the network can be assigned individual rights, depending on what must be allowed for that user.

What are the functions of a network administrator?

A network administrator has many responsibilities that can be summarize into 3 key functions: installation of a network, configuration of network settings, and maintenance/troubleshooting of networks.

What happens when you use cables longer than the prescribed length?

Cables that are too long would result in signal loss. This means that data transmission and reception would be affected, because the signal degrades over length.

What are routers?

Routers can connect two or more network segments. These are intelligent network devices that store information in its routing table such as paths, hops and bottlenecks. With this info, they are able to determine the best path for data transfer. Routers operate at the OSI Network Layer.

What is ipconfig?

Ipconfig is a utility program that is commonly used to identify the addresses information of a computer on a network. It can show the physical address as well as the IP address.

What is NIC?

NIC is short for Network Interface Card. This is a peripheral card that is attached to a PC in order to connect to a network. Every NIC has its own MAC address that identifies the PC on the network.

How are IP addresses arranged and displayed?

IP addresses are displayed as a series of four decimal numbers that are separated by period or dots. Another term for this arrangement is the dotted decimal format. An example is 192.168.101.2

What is the advantage of address sharing?

By using address translation instead of routing, address sharing provides an inherent security benefit. That’s because host PCs on the Internet can only see the public IP address of the external interface on the computer that provides address translation and not the private IP addresses on the internal network.

What is one basic requirement for establishing VLANs?

A VLAN is required because at switch level there is only one broadcast domain, it means whenever new user is connected to switch this information is spread throughout the network. VLAN on switch helps to create separate broadcast domain at  switch level. It is used for security purpose.

Describe at one disadvantage of a peer to peer network.

When you are accessing the resources that are shared by one of the workstations on the network, that workstation takes a performance hit.

What common software problems can lead to network defects?

Software related problems can be any or a combination of the following:

– client server problems


– application conflicts


– error in configuration


– protocol mismatch


– security issues


– user policy and rights issues

What is point to point link?

It refers to a direct connection between two computers on a network. A point to point connection does not need any other network devices other than connecting a cable to the NIC cards of both computers.

What is the difference between a straight-through and crossover cable?

A straight-through cable is used to connect computers to a switch, hub or router. A crossover cable is used to connect two similar devices together, such as a PC to PC or Hub to hub.

What is WAN?

WAN stands for Wide Area Network. It is an interconnection of computers and devices that are geographically dispersed. It connects networks that are located in different regions and countries.

Explain the importance of authentication.

Authentication is the process of verifying a user’s credentials before he can log into the network. It is normally performed using a username and password. This provides a secure means of limiting the access from unwanted intruders on the network.

What are MAC addresses?

MAC, or Media Access Control, uniquely identifies a device on the network. It is also known as physical address or Ethernet address. A MAC address is made up of 6-byte parts.

What is IPv6?

IPv6 , or Internet Protocol version 6, was developed to replace IPv4. At present, IPv4 is being used to control internet traffic, butis expected to get saturated in the near future. IPv6 was designed to overcome this limitation.

What is Hybrid Network?

A hybrid network is a network setup that makes use of both client-server and peer-to-peer architecture.

What is ICMP?

ICMP is Internet Control Message Protocol. It provides messaging and communication for protocols within the TCP/IP stack. This is also the protocol that manages error messages that are used by network tools such as PING.

What is anonymous FTP?

Anonymous FTP is a way of granting user access to files in public servers. Users that are allowed access to data in these servers do not need to identify themselves, but instead log in as an anonymous guest.

What is client/server?

Client/server is a type of network wherein one or more computers act as servers. Servers provide a centralized repository of resources such as printers and files. Clients refers to workstation that access the server.

What is the importance of the OSI Physical Layer?

The physical layer does the conversion from data bits to electrical signal, and vice versa. This is where network devices and cable types are considered and setup.

What do mean by tunnel mode?

This is a mode of data exchange wherein two communicating computers do not use IPSec themselves. Instead, the gateway that is connecting their LANs to the transit network creates a virtual tunnel that uses the IPSec protocol to secure all communication that passes through it.

What is the equivalent layer or layers of the TCP/IP Application layer in terms of OSI reference model?

The TCP/IP Application layer actually has three counterparts on the OSI model: the Session layer, Presentation Layer and Application Layer.

What is RSA algorithm?

RSA is short for Rivest-Shamir-Adleman algorithm. It is the most commonly used public key encryption algorithm in use today.

What is DHCP?

DHCP is short for Dynamic Host Configuration Protocol. Its main task is to automatically assign an IP address to devices across the network. It first checks for the next available address not yet taken by any device, then assigns this to a network device.

What is Ping?

Ping is a utility program that allows you to check connectivity between network devices on the network. You can ping a device by using its IP address or device name, such as a computer name.

What is subnet mask?

A subnet mask is combined with an IP address in order to identify two parts: the extended network address and the host address. Like an IP address, a subnet mask is made up of 32 bits.

Describe networking.

Networking refers to the inter connection between computers and peripherals for data communication. Networking can be done using wired cabling or through wireless link.

How many layers are there under TCP/IP?

There are four layers: the Network Layer, Internet Layer, Transport Layer and Application Layer.

What are the different technologies involved in establishing WAN links?

Analog connections – using conventional telephone lines; Digital connections – using digital-grade telephone lines; switched connections – using multiple sets of links between sender and receiver to move data.

How can you identify the IP class of a given IP address?

By looking at the first octet of any given IP address, you can identify whether it’s Class A, B or C. If the first octet begins with a 0 bit, that address is Class A. If it begins with bits 10 then that address is a Class B address. If it begins with 110, then it’s a Class C network.

What is mesh topology?

Mesh topology is a setup wherein each device is connected directly to every other device on the network. Consequently, it requires that each device have at least two network connections.

What is the main job of the ARP?

The main task of ARP or Address Resolution Protocol is to map a known IP address to a MAC layer address.

What is peer to peer?

Peer to peer are networks that does not reply on a server. All PCs on this network act as individual workstations.

What is the maximum length allowed for a UTP cable?

A single segment of UTP cable has an allowable length of 90 to 100 meters. This limitation can be overcome by using repeaters and switches.

When you move the NIC cards from one PC to another PC, does the MAC address gets transferred as well?

Yes, that’s because MAC addresses are hard-wired into the NIC circuitry, not the PC. This also means that a PC can have a different MAC address when the NIC card was replace by another one.

What are proxy servers and how do they protect computer networks?

Proxy servers primarily prevent external users who identifying the IP addresses of an internal network. Without knowledge of the correct IP address, even the physical location of the network cannot be identified. Proxy servers can make a network virtually invisible to external users.

What is one advantage of mesh topology?

In the event that one link fails, there will always be another available. Mesh topology is actually one of the most fault-tolerant network topology.

What is the main purpose of OSPF?

OSPF, or Open Shortest Path First, is a link-state routing protocol that uses routing tables to determine the best possible path for data exchange.

what is the maximum segment length of a 100Base-FX network?

The maximum allowable length for a network segment using 100Base-FX is 412 meters. The maximum length for the entire network is 5 kilometers.

What is TCP/IP?

TCP/IP is short for Transmission Control Protocol / Internet Protocol. This is a set of protocol layers that is designed to make data exchange possible on different types of computer networks, also known as heterogeneous network.

What is DNS?

DNS is Domain Name System. The main function of this network service is to provide host names to TCP/IP address resolution.

What is data encapsulation?

Data encapsulation is the process of breaking down information into smaller manageable chunks before it is transmitted across the network. It is also in this process that the source and destination addresses are attached into the headers, along with parity checks.

Explain clustering support

Clustering support refers to the ability of a network operating system to connect multiple servers in a fault-tolerant group. The main purpose of this is the in the event that one server fails, all processing will continue on with the next server in the cluster.

What is the function of the OSI Session Layer?

This layer provides the protocols and means for two devices on the network to communicate with each other by holding a session.  This includes setting up the session, managing information exchange during the session, and tear-down process upon termination of the session.

When troubleshooting computer network problems, what common hardware-related problems can occur?

A large percentage of a network is made up of hardware. Problems in these areas can range from malfunctioning hard drives, broken NICs and even hardware startups. Incorrectly hardware configuration is also one of those culprits to look into.

What are firewalls?

Firewalls serve to protect an internal network from external attacks. These external threats can be hackers who want to steal data or computer viruses that can wipe out data in an instant. It also prevents other users from external networks from gaining access to the private network.

How can you manage a network using a router?

Routers have built in console that lets you configure different settings, like security and data logging. You can assign restrictions to computers, such as what resources it is allowed access, or what particular time of the day they can browse the internet. You can even put restrictions on what websites are not viewable across the entire network.

What advantages does fiber optics have over other media?

One major advantage of fiber optics is that is it less susceptible to electrical interference. It also supports higher bandwidth, meaning more data can be transmitted and received. Signal degrading is also very minimal over long distances.

Describe Network Topology

Network Topology refers to the layout of a computer network. It shows how devices and cables are physically laid out, as well as how they connect to one another.

In a network that contains two servers and twenty workstations, where is the best place to install an Anti-virus program?

An anti-virus program must be installed on all servers and workstations to ensure protection. That’s because individual users can access any workstation and introduce a computer virus when plugging in their removable hard drives or flash drives.

What is the importance of implementing a Fault Tolerance System? Are there limitations?

A fault tolerance system ensures continuous data availability. This is done by eliminating a single point of failure. However, this type of system would not be able to protect data in some cases, such as in accidental deletions.

What can be done to fix signal attenuation problems?

A common way of dealing with such a problem is to use repeaters and hub, because it will help regenerate the signal and therefore prevent signal loss. Checking if cables are properly terminated is also a must.

Describe star topology

Star topology consists of a central hub that connects to nodes. This is one of the easiest to setup and maintain.

What protocol can be applied when you want to transfer files between different platforms, such between UNIX systems and Windows servers?

Use FTP (File Transfer Protocol) for file transfers between such different servers. This is possible because FTP is platform independent.

What is the difference between a hub and a switch?

A hub acts as a multiport repeater. However, as more and more devices connect to it, it would not be able to efficiently manage the volume of traffic that passes through it. A switch provides a better alternative that can improve the performance especially when high traffic volume is expected across all ports.

What is VPN?

VPN means Virtual Private Network, a technology that allows a secure tunnel to be created across a network such as the Internet. For example, VPNs allow you to establish a secure dial-up connection to a remote server.

Describe Ethernet

Ethernet is one of the popular networking technologies used these days. It was developed during the early 1970s and is based on specifications as stated in the IEEE. Ethernet is used in local area networks.

What does 10Base-T mean?

The 10 refers to the data transfer rate, in this case is 10Mbps. The word Base refers to base band, as oppose to broad band. T means twisted pair, which is the cable used for that network.

How does dynamic host configuration protocol aid in network administration?

Instead of having to visit each client computer to configure a static IP address, the network administrator can apply dynamic host configuration protocol to create a pool of IP addresses known as scopes that can be dynamically assigned to clients.

What are gateways?

Gateways provide connectivity between two or more network segments. It is usually a computer that runs the gateway software and provides translation services. This translation is a key in allowing different systems to communicate on the network.

What is the use of a default gateway?

Default gateways provide means for the local networks to connect to the external network. The default gateway for connecting to the external network is usually the address of the external router port.

What is a Link?

A link refers to the connectivity between two devices. It includes the type of cables and protocols used in order for one device to be able to communicate with the other.

What are the different network protocols that are supported by Windows RRAS services?

There are three main network protocols supported: NetBEUI, TCP/IP, and IPX.

Briefly describe NAT.

NAT is Network Address Translation. This is a protocol that provides a way for multiple computers on a common network to share single connection to the Internet.

What are some drawbacks of implementing a ring topology?

In case one workstation on the network suffers a malfunction, it can bring down the entire network. Another drawback is that when there are adjustments and reconfigurations needed to be performed on a particular part of the network, the entire network has to be temporarily brought down as well.

What is a private IP address?

Private IP addresses are assigned for use on intranets. These addresses are used for internal networks and are not routable on external public networks. These ensures that no conflicts are present among internal networks while at the same time the same range of private IP addresses are reusable for multiple intranets since they do not “see” each other.

Explain profile in terms of networking concept?

Profiles are the configuration settings made for each user. A profile may be created that puts a user in a group, for example.

What is the disadvantage of a star topology?

One major disadvantage of star topology is that once the central hub or switch get damaged, the entire network becomes unusable.

MySQL Interview Questions and Answers PDF Download

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What are the technical features of MySQL?

MySQL database software is a client or server system which includes

  • Multithreaded SQL server supporting various client programs and libraries
  • Different backend
  • Wide range of application programming interfaces and
  • Administrative tools.
What storage engines are used in MySQL?

Storage engines are called table types and data is stored in files using various techniques.

Technique involves:

  • Storage mechanism
  • Locking levels
  • Indexing
  • Capabilities and functions.
What do you mean by % and _ in the LIKE statement?

% corresponds to 0 or more characters, _ is exactly one character in the LIKE statement.

How MySQL Optimizes DISTINCT?

DISTINCT is converted to a GROUP BY on all columns and it will be combined with ORDER BY clause.

SELECT DISTINCT t1.a FROM t1,t2 where t1.a=t2.a;

Why MySQL is used?

MySQL database server is reliable, fast and very easy to use.  This software can be downloaded as freeware and can be downloaded from the internet.

What are the drivers in MySQL?

Following are the drivers available in MySQL:

  • PHP Driver
  • JDBC Driver
  • ODBC Driver
  • C WRAPPER
  • PYTHON Driver
  • PERL Driver
  • RUBY Driver
  • CAP11PHP Driver
  • Ado.net5.mxj
How can we convert between Unix & MySQL timestamps?

UNIX_TIMESTAMP is the command which converts from MySQL timestamp to Unix timestamp

FROM_UNIXTIME is the command which converts from Unix timestamp to MySQL timestamp.

How to enter Characters as HEX Numbers?

If you want to enter characters as HEX numbers, you can enter HEX numbers with single quotes and a prefix of (X), or just prefix HEX numbers with (Ox).

A HEX number string will be automatically converted into a character string, if the expression context is a string.

What are Heap tables?

HEAP tables are present in memory and they are used for high speed storage on temporary basis.

• BLOB or TEXT fields are not allowed

• Only comparison operators can be used =, <,>, = >,=<

• AUTO_INCREMENT is not supported by HEAP tables

• Indexes should be NOT NULL

What does a TIMESTAMP do on UPDATE CURRENT_TIMESTAMP data type?

TIMESTAMP column is updated with Zero when the table is created.  UPDATE CURRENT_TIMESTAMP modifier updates the timestamp field to current time whenever there is a change in other fields of the table.

What are the column comparisons operators?

The = , <>, <=, <, >=, >,<<,>>, <=>, AND, OR, or LIKE operators are used in column comparisons in SELECT statements.

How to display top 50 rows?

In MySql, top 50 rows are displayed by using this following query:

SELECT * FROM

LIMIT 0,50; 

What is the default port for MySQL Server?

The default port for MySQL server is 3306.

What is the difference between primary key and candidate key?

Every row of a table is identified uniquely by primary key. There is only one primary key for a table.

Primary Key is also a candidate key. By common convention, candidate key can be designated as primary and which can be used for any foreign key references.

How can we get the number of rows affected by query?

Number of rows can be obtained by

SELECT COUNT (user_id) FROM users;

How many columns can be used for creating Index?

Maximum of 16 indexed columns can be created for any standard table.

What are the advantages of MySQL when compared with Oracle?
  • MySQL is open source software which is available at any time and has no cost involved.
  • MySQL is portable
  • GUI with command prompt.
  • Administration is supported using MySQL Query Browser
How do you login to MySql using Unix shell?

We can login through this command:

# [mysql dir]/bin/mysql -h hostname -u <UserName> -p <password>

Is Mysql query is case sensitive?

No.

SELECT VERSION(), CURRENT_DATE;

SeLect version(), current_date;


seleCt vErSiOn(), current_DATE;

All these examples are same. It is not case sensitive.

What is the different between NOW() and CURRENT_DATE()?

NOW () command is used to show current year,month,date with hours,minutes and seconds.

CURRENT_DATE() shows current year,month and date only.

Differentiate between FLOAT and DOUBLE?

Following are differences for FLOAT and DOUBLE:

• Floating point numbers are stored in FLOAT with eight place accuracy and it has four bytes.

• Floating point numbers are stored in DOUBLE with accuracy of 18 places and it has eight bytes.

What does myisamchk do?

It compress the MyISAM tables, which reduces their disk or memory usage.

What is the difference between the LIKE and REGEXP operators?

LIKE and REGEXP operators are used to express with ^ and %.

SELECT * FROM employee WHERE emp_name REGEXP “^b”;

SELECT * FROM employee WHERE emp_name LIKE “%b”; 

What are the objects can be created using CREATE statement?

Following objects are created using CREATE statement:

  • DATABASE
  • EVENT
  • FUNCTION
  • INDEX
  • PROCEDURE
  • TABLE
  • TRIGGER
  • USER
  • VIEW
Differentiate CHAR_LENGTH and LENGTH?

CHAR_LENGTH  is character count whereas the LENGTH is byte count. The numbers are same for Latin characters but they are different for Unicode and other encodings.

How do you control the max size of a HEAP table?

Maximum size of Heal table can be controlled by MySQL config variable called max_heap_table_size.

What is the difference between BLOB AND TEXT?

A BLOB is a binary large object that can hold a variable amount of data. There are four types of BLOB –

  • TINYBLOB
  • BLOB
  • MEDIUMBLOB and
  • LONGBLOB

They all differ only in the maximum length of the values they can hold.

A TEXT is a case-insensitive BLOB. The four TEXT types

  • TINYTEXT
  • TEXT
  • MEDIUMTEXT and
  • LONGTEXT

They all correspond to the four BLOB types and have the same maximum lengths and storage requirements.

The only difference between BLOB and TEXT types is that sorting and comparison is performed in case-sensitive for BLOB values and case-insensitive for TEXT values.

How many TRIGGERS are allowed in MySql table?

SIX triggers are allowed in MySql table. They are as follows:

  • BEFORE INSERT
  • AFTER INSERT
  • BEFORE UPDATE
  • AFTER UPDATE
  • BEFORE DELETE and
  • AFTER DELETE
How to represent ENUMs and SETs internally?

ENUMs and SETs are used to represent powers of two because of storage optimizations.

What is the difference between MyISAM Static and MyISAM Dynamic?

In MyISAM static all the fields will have fixed width. The Dynamic MyISAM table will have fields like TEXT, BLOB, etc. to accommodate the data types with various lengths.

MyISAM Static would be easier to restore in case of corruption.

What is the difference between mysql_fetch_array and mysql_fetch_object?

Following are the differences between mysql_fetch_array and mysql_fetch_object:

mysql_fetch_array() -Returns a result row as an associated array or a regular array from database.

mysql_fetch_object –  Returns a result row as object from database.

What are the nonstandard string types?

Following are Non-Standard string types:

  • TINYTEXT
  • TEXT
  • MEDIUMTEXT
  • LONGTEXT
What is the usage of ENUMs in MySQL?

ENUM is a string object used to specify set of predefined values and that can be used during table creation.

Create table size(name ENUM(‘Small’, ‘Medium’,’Large’);

What are federated tables?

Federated tables which allow access to the tables located on other databases on other servers.

How can we run batch mode in mysql?

Following commands are used to run in batch mode:

mysql ;

mysql mysql.out 

What are all the Common SQL Function?

CONCAT(A, B) – Concatenates two string values to create a single string output. Often used to combine two or more fields into one single field.

FORMAT(X, D) – Formats the number X to D significant digits.

CURRDATE(), CURRTIME() – Returns the current date or time.

NOW() – Returns the current date and time as one value.

MONTH(), DAY(), YEAR(), WEEK(), WEEKDAY() – Extracts the given data from a date value.

HOUR(), MINUTE(), SECOND() – Extracts the given data from a time value.

DATEDIFF(A, B) – Determines the difference between two dates and it is commonly used to calculate age

SUBTIMES(A, B) – Determines the difference between two times.

FROMDAYS(INT) – Converts an integer number of days into a date value.

Define REGEXP?

REGEXP is a pattern match in which  matches pattern anywhere in the search value.

What, if a table has one column defined as TIMESTAMP?

Timestamp field gets the current timestamp whenever the row gets altered.

Where MyISAM table will be stored and also give their formats of storage?

Each MyISAM table is stored on disk in three formats:

  • The ‘.frm’ file stores the table definition
  • The data file has a ‘.MYD’ (MYData) extension
  • The index file has a ‘.MYI’ (MYIndex) extension
Explain Access Control Lists.

An ACL (Access Control List) is a list of permissions that is associated with an object. This list is the basis for MySQL server’s security model and it helps in troubleshooting problems like users not being able to connect.

MySQL keeps the ACLs (also called grant tables) cached in memory. When a user tries to authenticate or run a command, MySQL checks the authentication information and permissions against the ACLs, in a predetermined order.

Difference between CHAR and VARCHAR?

Following are the differences between CHAR and VARCHAR:

  • CHAR and VARCHAR types differ in storage and retrieval
  • CHAR column length is fixed to the length that is declared while creating table. The length value ranges from 1 and 255
  • When CHAR values are stored then they are right padded using spaces to specific length. Trailing spaces are removed when CHAR values are retrieved.
What happens when the column is set to AUTO INCREMENT and if you reach maximum value in the table?

It stops incrementing. Any further inserts are going to produce an error, since the key has been used already.

What are the different tables present in MySQL?

Total 5 types of tables are present:

  • MyISAM
  • Heap
  • Merge
  • INNO DB
  • ISAM

MyISAM is the default storage engine as of MySQL .

Give string types available for column?

The string types are:

  • SET
  • BLOB
  • ENUM
  • CHAR
  • TEXT
  • VARCHAR
How can we find out which auto increment was assigned on Last insert?

LAST_INSERT_ID will return the last value assigned by Auto_increment and it is not required to specify the table name.

What is ISAM?

ISAM  is abbreviated as Indexed Sequential Access Method.It was developed by IBM to store and retrieve data on secondary storage systems like tapes.

What is MySQL?

MySQL is an open source DBMS which is built, supported and distributed by MySQL AB (now acquired by Oracle)

How to get current MySQL version?

SELECT VERSION (); is used to get the current version of MySQL.

How can you see all indexes defined for a table?

Indexes are defined for the table by:

SHOW INDEX FROM <tablename>;

What is InnoDB?

lnnoDB is a transaction safe storage engine developed by Innobase Oy which is a Oracle Corporation now.

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What is VSAM?

VSAM stands for Virtual Storage Access Method. It’s a Data Management method used to organize, store, catalog, retrieve and delete the datasets in mainframe system (VSAM and Non-VSAM). This access method makes it easier for an application to execute an I/O operation (moving data between an I/O device and memory). In fact VSAM is the first access method designed for Virtual Storage Environment.

VSAM supports fixed as well as variable length records. These records are placed in blocks of Control Intervals and these control intervals are further placed as Control Area (CA consists of multiple CIs).

What are the advantages of VSAM?

Accessing the data is faster and easier.
VSAM supports more dataset types.
Supports variety of I/O Techniques.
Improves Efficiency.
Records can be accessed sequentially or randomly.

What are the disadvantages of VSAM?

VSAM Datasets require more storage space compared to other type of datasets due to Control information(CI) present in them.
VSAM can’t be stored in TAPE Volume i.e., VSAM Stored only in DASD.
VSAM is not a database like DB2, IMS DB & IDMS.

What are the different types of VSAM files available?

ESDS: Entry Sequence Data Set
KSDS: Key Sequence Data Set
RRDS: Relative Data Set

What is purpose of VSAM?

VSAM acts as an interface between Application program & Operating System.

What is the maximum record length for the VSAM dataset?

Max size of a record in VSAM is cylinder = 2880 bytes approx.

What is an alternate index and path?

An alternate index is an another way of accessing key sequenced data record stored in a base cluster and path is the linkage which connect alternate index to its base cluster.

Is a delete operation possible in an ESDS? B, is rewrite operation possible in ESDS?

No delete operation is not possible in VSAM ESDS.B. yes rewrite operation is possible in an ESDS.

What is the difference between LDS and ESDS?

There two datasets are VSAM datasets. ESDS maintains control information. But LDS does not maintains the control information.

How to delete a member using JCL?

Using IDCAMS a member can be deleted. DELETE ‘XXX.YYY (memeber)

What is IDCAMS? and what is the purpose of it?

IDCAMS is an access method services utility used for creating, deleting, altering VSAM files and coping sequential file to a VSAM file, etc.

What are the optional parameters to the input dataset While loading the empty cluster with the data records?

1) FROMADDRESS(address)
2) TOADDRESS(address) where ‘address’ specifies the RBA value of the key of the input record.
3) FROMNUMBER (rrn)
4)TONUMBER (rrn) where ‘rrn’ specifies the relative record number of the RRDS record
5) FROMKEY (key)
6) TOKEY (key) where ‘key’ specifies the key of the input record
7) SKIP (number)
8) COUNT (number) where ‘number’ specifies the number of records to skip or copy Ex: REPRO INFILE(DD1) OUTFILE(DD2) SKIP(9000) COUNT(700)-Skips the first 9000 records and begin copying at 9001 and copies 700 records from DD1 to DD2.

What does the KEYRANGES parameter in Define Cluster commends do?

It divides a large dataset into several volumes according to the Key ranges specified. e.g. KEYRANGES ((0000001 2999999) (3000000 5999999)). if the activity on the key ranges are evenly distributed, concurrent access is possible, which is a performance improvement.

Describe SHAREOPTIONS parameter (SHR) in Define Cluster command?

It define the cross-region and cross-system sharing capabilities of the dataset. Syntax is SHR (Crvalue, CSvalue) value 1 means multiple read OR single write (read integrity ) 2 means multiple read AND single write ( Write integrity ) 3 means Multiple read AND multiple write 4 is same as 3, which refreshes the buffer with every random access default is SHR(1 3).

What is RECOVERY and SPEED parameters in DEFINE CLUSTER command?

RECOVERY (default ) and SPEED are mutually exclusive. Recovery pre-formats the control areas during the initial dataset load, if the job fails, you can restart but you must have a recovery routine already written to restart the job. SPEED does not pre-format the CAs. It is recommended that you specify SPEED to speed up your initial data load.

Is it slower if you access a record through ALT INDEX as compared to Primary INDEX?

Yes. Why Because the alternate key would first locate the primary key, which in turn locates the actual record. Needs twice the number of I/Os.

How many Alternate Indexes you can have on a dataset?

255 – but you must be a nut to have so many ALT Indexes on a dataset!

On which dataset You can have ALT INDEX?

Only on KSDS and ESDS – not RROS

What is the meaning of VSAM RETURN-CODE 28?

Out of space condition is raised.

How do you fix the problem associated with VSAM out of space condition?

Define new VSAM dataset allocated with more space.
Use IDCAMS to REPRO the old VSAM file to new VSAM dataset.
Use IDCAMS to ALTER / rename the old VSAM dataset or se IDCAMS to DELETE the old VSAM datset.
Use IDCAMS to ALTER / rename the new VSAM dataset to the name of the original VSAM dataset.

During processing of a VSAM file, some system error occurs and it is subsequently unusable What do you do?

Run VERIFY.

Suppose a generation of GDG gets created in a particular step of a proc. How would you refer the current generation in a subsequent step? What would be the disposition of this generation now?

Relative generation numbers are updated only at the end of the job, not at the end of a step. To allocate a new generation, we would be using (+1) with a DISP of ( NEW, CATLG, DELETE ). To refer to this in a subsequent step in the same job, we would again use (+1) but with a DISP of SHR or OLD.

How are different versions of GDG named?

base-file-name. GnnnnnnV00 where nnnn=generation number (upto 255). nnnn will be 0000 for the 1st generation.

How do you define a GDG?

Use the DEFINE GENERATIONDATAGROUP command. In the same IDCAMS step, another dataset must be defined whose DCB parameters are used when new generations of the GDG are created. This dataset is known as the model dataset. The DS name of this model dataset must be the same as that of the GDG, so use a disp of keep rather than catlg and also specify space = (trk,0)

What is the difference between sequential files and ESDS files?

Sequential (QSAM) files can be created on tape while ESDS files cannot. Also, you can have ALTINDEX for an ESDS while no such facility exists for QSAM files.

How do you calculate record size of an alternate cluster? Give your values for both unique and nonunique?

UniqueCase: 5 + (alt-key-length + primary – key )

Non unique Case: 5 + (alt-key-length + n * primary – key ) where n = number of duplicate records for the alternate key

How do you load a VSAM data set with records?

Using the REPRO command.

Do all versions of the GDG have to be of the same record length?

No, the DCB of the model dataset can be overridden when you allocate new versions.

Suppose 3 generations of a GDG exist. How would you reference the 1st generation in the JCL?

Use GDG name(-2).

What more info you should give in the DD statement while defining the next generation of a GDG?

Give (+1) as the generation number, give (new, catlg) for disp, give space parameter, can give the DCB parameter if you want to override the DCB of the model dataset.

Assuming that the DEFINE JCL is not available, how do you get info about a VSAM files organisation?

Use the LISTCAT command.

Using Alternate Indexes in CICS program?

FCT entries must be created for both base cluster and the path. To read using the alternate index, use the DD name of the path in CICS file control commands.

Using Alternate Indexes in Batch program?

In the JCL, you must have DD statements for the cluster and for the path9s). In the COBOL program, SELECT … ASSIGN TO ddname for base cluster RECORD KEY IS… ALTERNATE RECORD KEY IS …

What is a LDS (Linear Data Set) and what is it used for?

LDS is a VSAM dataset in name only. It has unstructured 4k (4096 bytes ) fixed size CT’s which do not contain control fields and therefore from VSAM’s standpoint they do not contain any logical records. There is no free space, and no access from Cobol. Can be accessed by DB2 and IMS fast path datasets. LDS is essentially a table of data maintained on disk. The ‘table entries’ must be created via a user program and can only be logically accessed via a user program. When passed, the entire LDS must be mapped into storage, and then data is accessed via base and displacement type processing.

What is the meaning of the DEFINE MODEL parameter?

It specifies whether Daniela Pestova or Yamila – oops! Wrong models! The MODEL parameter allows you to model your cluster by modeling it after an existing cluster.

What are the three levels of definition for the VSAM DEFINE?

They are DEFINE CLUSTER, DATA and INDEX.

What is the utility program closely associated with VSAM?

IDCAMS, the access method services utility.

What is the VSAM-code field?

It is a COBOL II enchancement to VSAM batch processing expanding the FILE STATUS field. It is defined in WORKING-STORAGE as a six byte group item with three two byte elements, the normal return code, the function code and the feedback code.

What is the meaning of dynamic processing?

It’s rarely used. It means one program uses both sequential and random processing for a VSAM KSDS file.

Under IDCAMS, multiple functions can be executed, each of which returns a condition code. What will be the condition code returned to the operating system?

The maximum condition code generated is returned as the condition code of the IDCAMS step.

Would you specify FREESPACE CE for an ESDS?

No. Because you cannot insert records in an ESDS, also when you rewrite a record, it must be of the same length. Thus putting any value for FREESPACE does not make any sense.

What is the meaning of each of the values in SHAREOPTS (2 3)?

Value of 2 for cross region means that the file can be processed simultaneously by multiple users provided only one of them is an updater. Value of 3 for cross system means that any number of jobs can process the file for input or output (VSAM does nothing to ensure integrity).

How do you define an ALTINDX? How do you use ALTINDXs in batch, CICS programs?

DEFINE ALTERNATEINDEX. Important parameters are RELATE where you specify the base cluster name, KEYS, RECORDSIZE, SHAREOPTION, UNIQUEKEY (or NONUNIQUEKEY), DATA (DS NAME for the data component), INDEX(DS name for the index component). Then DEFINE PATH. Important parameters are NAME (DS name for the path). PATHENTRY (DS name of the alternate index name). UPDATE (or NOUPDATE) which specifies whether an ALT index is updated when a update to the vase cluster takes place. Then BLDINDEX. Paramters are INDATASET (DS name of base cluster), OUTDATASET (DS name of AIX).

Name some common VSAM error conditions and codes?

They are end of file (10), duplicate key (22), record not found (23), VSAM logic error (90), open problem (92) and space problem (93).

What is a VSAM slot?

A relative record dataset (RRDS) consists of a specified number of areas called slots. Each slot is identified by a relative record number (RRN) which indicates its relative position in the file.

There are at least seven IDCAMS commands name and explain each of them?

ALTER modifies information for a catalog, alternate index, cluster or path. BLDINDEX builds the alternate index, of course. DEFINE is used for ALTERNATEINDEX, CLUSTER or PATH. DELETE removes the catalog entry for a catalog, cluster, alternate index or path. LISTCAT lists information about the dataset. PRINT prints the dataset contents. REPRO copies records from one file to another.

What is the significance of the SHAREOPTIONS parameter?

It specifies how the file may be shared between jobs and between batch and CICS environments.

What is File Status in VSAM?

The File STATUS clause of the FILE-CONTROL paragraph allows for each file to be associated with a file status key (i.e., the 2-character data item specified in the FILE STATUS clause). If the FILE STATUS clause is specified for a given file, a value indicating the status of each I/O operation against that file is placed in the associated file status key. This value is stored in the file status key as soon as the I/O operation is completed (and before execution of any EXCEPTION/ERROR declarative or INVALIDKEY/AT END phrase associated with the I/O request).

Note: This element may behave differently when the CMPR2 compiler option is used. The file status key is divided into two status keys: the first character is known as file status key1; the second character is file status key 2.

If you wish to use the REWRITE command haw must the VSAM file be opened?

It must be opened as I/O.

What is the COBOL RECORD KEY clause?

The RECOED KEY in the SELECT clause identifies the files primary key as it will be known to the program.

In the COBOL SELECT statement what is the ORGANIZATION for a KSDS?

The ORGANIZATION is INDEXED.

What is the base cluster?

The base cluster consists of the data component and the index component for the primary index of a KSDS.

What is free space?

Free space is reserved within the data component of a KSDS to accommodate inserting new records.

What is a path?

A path is a file that allows you to access a file by alternate index – the path provides an association between the AIX and the base cluster.

What is a CI, control interval?

A control interval is the unit of information that VSAM transfers between virtual and auxilliary storage.

What is a CA, control area?

A group of control intervals makes up a control area.

What is the index set?

This is the other part of the index. It has multiple levels with pointers that ultimately reach to the sequence set.

What is the catalog?

The catalog contains the name of all datasets. VSAM and non-VSAM. It is used to access these datasets.

What is the purpose of the FILE STATUS clause in the SELECT statement?

The FILE STATUS field identifies the field that VSAM uses to provide information about each I/O operation for the file.

In the COBOL SELECT statement for a KSDS what are the three possibilities for ACCESS?

ACCESS can be SEQUENTIAL, RANDOM or DYNAMIC.

Do primary key values have to be unique? Do alternate key values have to be unique?

Primary key values must be unique; alternate key values need not be.

What is a VSAM split?

If there isn’t enough space in the control interval VSAM performs a control interval split by moving some records to the free control intervals. If there isn’t a free control interval VSAM performs a control area split by allocating a new control area and moving half of the control intervals to it.

What is the upgrade set?

The upgrade set is the list of all AIXes that VSAM must maintain for a specific base cluster, so that when data in the base cluster is updated, the AIX files are also updated.

What is an alternate index?

An AIX is a file that allows access to a VSAM dataset by a key other than the primary one.

What is a cluster?

A cluster is the combination of the index, sequence set and data portions of the dataset. The operating system gives program access to the cluster, ie. to all parts of the dataset simultaneously.

What is a sequence set?

This is the part of the index that points to the CA and CI of the record being accessed.

What are the distinctive features of a KSDA, key sequenced dataset?

The index and the distributed free space.

How are records stored in an ESDS, entry sequenced dataset?

They are stored without respect to the contents of the records and in the order in which they are included in the file.

What are the types of VSAM datasets?

Entry sequenced dataset (ESDS), key sequenced datasets (KSDS) and relative record dataset (RRDS).

AutoCAD Interview Questions and Answers PDF Download

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List of AutoCAD Interview Questions and Answers PDF

What is AutoCAD?

AutoCAD is a software program built to design and shape the 2-D and 3-D images.  It provides the tools by which a detail design of the product can be done. It also has the option to create detailed design layout, which can be automatically drawn by using source model.

What are the uses of Autocad?

Autocad can be used by the professionals to visualize the imaginary view of the product on a computer system. In Autocad, it is possible by the drafter to make the changes in the product before it gets finalized for design. It also gives the freedom for the designer to implement their various ideas and represent them to the suppliers or their clients.

What are the fields where you see maximum use of Autocad?

Autocad is more popular among the architects, engineers and builders for developing their building layouts.

What is the file formats used in design?

In Autocad, .dwg file format is used for design, it can be an interchangeable format.  The file format which is interchangeable has the extension as DXF and operates data operability. It provides different languages which can be used as per the requirement.

How you can create a user interface in Autocad?

User interface can be created by using the command prompts to draw the plots and dialog boxes. The dialog boxes can be displayed by the use of PLOT command and the external database commands (ASE).  Setting of CMDDIA to 1, allows the dialog boxes to run the command.  The user interface creation also needs the command line to display the entire file so that it can be edited or customized easily.

What is the function of vertical integration?

To enhance the architectural designing of 3D object Autocad uses the vertical integration program.  The 3D objects can include walls and other things that are associated with the data having information and simple objects like lines and circles. The data is programmed in such away that it represents only the architectural products and the extracted files, and can be modified according to the requirement.

What is the use of variant in Autocad?

In Autocad variants are used to help in creation, visualizing and rendering the 3D models that include 3D printing as well.  Variants allows you to use the functionality of different application according to the requirement.

What are the benefits of using Autocad?

Autocad has replaced the traditional method of drafting and designing which was made by pencil, drafting boards, triangles and compass with just a set of a computer program.  The benefits are immense like:

  • Saves time and helps to increase the productivity
  • It helps to streamline your design and documentation workflow
  • Physical ‘3D’ prototype of the design can be quickly created by using Autocad
  • 3D models can be directly imported into Autocad by using application like SolidWorks
  • Tedious work of drafting can be done easily and you can design and re-design the product in short span of time.
What is the process to draw a line more than one time and save it automatically?

When a need arises to draw a new line the process opens up a new file in a new session to write the file. Autocad allows saving multiple drawing for each session. The files are saved by using the file extension .dwg and it can be modified by using the browser.

What are the steps that enable the drag and drop feature in Autocad?

Autocad provides a way to drag and drop the elements by the use of “NOUN” and “VERB” in a dialog box.  It allows the object to move from one place to another.  Likewise, the remove or editing function can be done by using “MOVE and ERASE”.

What are the features corrected by Autocad?

Autocad detects the problem and correct it by removing the corruption with the drawing parts.  With the available option of adding additional vertices, it also adds vertices to the poly-lines. The error can be corrected or neglected by finding out the exact location of the poly-line that has zero vertices.  The object can be deleted or removed after there is no use of it in the system.

How to set up a default drawing directory?

Default drawing directory has sub directories having the information using the windows commands. The applications, which are going to be used, are highlighted, and by using drag and drop features those application will be placed in the default directory. The properties for the application are selected from the menu and dialog boxes displayed on the front.

How you can copy a closed drawing?

The copying of the closed drawing can be done by the designer center in the toolbar of the Autocad.  By using the tree view option the copy of closed drawing can be done easily. The modification of the drawing can be done by using graphical interface.

How you can hide the specific layers when plotting in Autocad?

To hide the specific layers while plotting, you can use various options like turning off the layers for plotting , freezing the layers and turning off. Turning off for plotting will show the layers on the screen but won’t output on printing. The layers that are turned off will hide the layers and also it will not appear on the screen.

What is the process of copying the dimension styles from one drawing to another in Autocad?

Copying of dimension styles require setting up the particular dimension style. To copy a dimension style, a new document has to be created. Once it is created, this document will be saved as a drawing template. A new reference will be created by new drawing template document and it will show all the options like layer style, units and blocks. Drawing can be done by seeing the current drawing and dimension style would be same as the original picture. By using the design center, Autocad tools can be used to copy the dimension styles from one drawing to another.

How can you remove the empty layers from drawing?

The layers can be removed only when the object resides in the layers will be removed, once it is removed it is an empty layer. The empty layers cannot be deleted by purge. It might be because the layer is frozen on a viewport or referenced by an object in a block definition. By using EXPORT command it is possible to remove the layer from drawing, which results in creating a DXF file of the drawing. You can edit the dxf file in a text editor and rename all the instances of layers in the file, except the layer definition.

Why Autocad WS is more popular among mobile users?

Autocad WS provides many option for mobile application developer like edit, view and share.  They can easily share the application wherever they go and can develop an application in a matter of time. The application can be downloaded and installed from anywhere in the world, ignoring the licensing problem. The users can save file in any format and can run the application on any platform with ease.

How can you make a spring, spiral or screw thread?

To make a spiral or screw thread use an AutoLISP routine such as spiral.1sp, it will create a spiral path according to your need. Then you can use EXTRUDE command with a reference object, using the spiral as the path.  Also, there is another way you can do this, by using Mechanical Desktop (MDT) or Autosurf by using augmented lines as path.

Tell me how you assign the keyboard characters or function keys to Autocad commands?

By editing the ACCELERATORS section of the Autocad menu file we can assign keyboard characters to Autocad commands.

How you can open a drawing file that was created with the automatic save features?

Autocad files have an extension of “.dwg” and will only open those files having this extension. To open the drawing files you have to rename it, by using Explorer or DOS prompt you can do that. If you are using EXPLORER you have to make sure that the option of “Hide file extensions for known file types” is not enabled. After the file is copied you can rename and use the OPEN command in Autocad to open the drawing.

What will you do when command prompts appear on the command line instead of ASE dialog box and plot dialog box?

In Autocad, CMDDIA variable controls the display of dialog boxes. To enable these dialog boxes you have to set CMDDIA to 1.

In Autocad, what is the command that is used to rotate the grid at 45 degress?

To rotate the grid at 45 degrees, command UCS is used.

In what situation command prompt appears instead of a dialog boxes?

If a file command is imported from a script or AutoLISP/ ObjectARX/ ADSRX a command prompt appears instead of a dialog box.

What are grips?

Grips are small boxes that appear on the objects you select.  You can move or edit an object by dragging a grip.

What you are supposed to do when “Enter Attributes” dialogue doesn’t display?

In this case, two variable controls this function, ATTREQ and ATTDIA , to see the “Enter Attributes” dialogue , make sure both the variables are set to 1 and not 0.

What is API testing?

API (Application Programming Interface) specifies how some software components should interact with other, in other words it’s a set of functions and procedures that allows the creation of applications which access the features or data of an application or operating system.   Testing of these functions is known as API testing.

What are the tools used for API testing?

The tools used for various API testing are

  • SoapUI Pro
  • LoadUI Pro
  • Alertsite API monitoring
What are the common tests performed on API’s?

The common tests performed on API’s

  • Verification of the API whether it is updating any data structure
  • Verify if the API does not return anything
  • Based on input conditions, returned values from the API’s are checked
  • Verification of the API whether it triggers some other event or calls another API
Mention the key difference between UI level testing and API testing?

UI ( User Interface) refers to testing graphical interface such as how user interacts with the applications, testing application elements like fonts, images, layouts etc. UI testing basically focuses on look and feel of an application.

While, API enables communication between two separate software systems. A software system implementing an API contains functions or sub-routines that can be executed by another software system

Explain what is SOAP?

SOAP-stands for Simple Object Access Control, and it is an XML based protocol for exchanging information between computers.

Explain what is REST API?

It is a set of functions to which the developers performs requests and receive responses. In REST API interaction is made via HTTP protocol

REST – stands for Representational State Transfer, it is quickly becoming defacto standard for API creation.

Difference API and Unit Testing?
                       API testing                          UNIT testing
  • API is owned by QA team
  • Unit testing is owned by development team
  • API is mostly black box testing
  • Unit testing is white box testing
  • Full functionality of the system is considered in API testing as it will be used by the end-user (external developers who will use your API )
  • Unit testing is done to verify whether each unit in isolation performs as expected or not
  • API test are often run after the build is ready and authors do not have access to the source code
  • For each of their module the developers are expected to build unit tests for each of their code modules and have to ensure that each module pass unit test before the code is included in a build
How to test API’s ?

To test the API’s you should follow the following steps

  • Select the suite in which you want to add the API test case
  • Choose test development mode
  • Develop test cases for the desired API methods
  • Configure application control parameters
  • Configure test conditions
  • Configure method validation
  • Execute API test
  • View test reports
  • Filter API test cases
  • Sequence API test cases
Mention what the main areas to be taken in consideration while writing API document ?

The key area to be considered when writing API documents are

  • Source of the content
  • Document plan or sketch
  • Delivery layout
  • Information required for each function in the document
  • Automatic document creation programs
In API document explain how to document each function ?What are the tools used for documentation?
  • Description: Small description about what a function does
  • Syntax: Syntax about the parameter of the code, the sequence in which they occur, required and optional elements etc.
  • Parameters: Functions parameters
  • Error Messages: Syntax of error messages
  • Example Code: Small snippet of code
  • Related Links: Related functions

Popular tools used for API documentations are JavaDoc (for Java code ) Doxygen (for .Net code)

Explain API framework?

API framework is self-explanatory. Values for test run and for holding the configurable parts, config file is used.  Automated test cases must represent in “ parse-table” format within config file.  When testing API, it is not necessary to test each API so the config file have some section whose all API are activated for that specific run.

How does the API Builder work?

API Builder is a PLSQL program consists of four SQL files

  • For setting API parameters and starting the process one file is responsible
  • Two files are created for temporary tables and Master package to create the outputted code
  • Fourth file creates “spooled” output of the code into a file called “output_script_.sql”
Explain what is TestApi ?

TestApi is a library of utility and test APIs that enables testers and developers to create testing tools and automated tests for .NET and Win32 application.  It provides a set of common test building blocks, types, data-structure and algorithms.

What is Input injection and what are different ways of doing it ?

Input Injection:  It is the act of simulating user input, in several ways you can simulate user input.

  • Direct Method Invocation
  • Invocation using an accessibility interface
  • Simulation using low-level input
  • Simulation using a device driver
  • Simulation using a robot
What are the main challenges of API testing?

The main challenges in API testing is

  • Parameter Selection
  • Parameter Combination
  • Call sequencing
What is API testing with runscope ?

Runscope is a web application that provides backend services and easy to use interface for testing APIs.

Explain what are the principles of API test design?

The principle for API test design are

  • Setup : Create objects, start services, initialize data etc
  • Execution: Steps to exercise API or scenario, also logging
  • Verification: Oracles to evaluate execution outcome
  • Reporting: Pass, failed or blocked
  • Clean up: Pre-test state
What are the types of Bugs will API testing finds?

The types of Bugs, API will find

  • Missing or duplicate functionality
  • Fails to handle error conditions gracefully
  • Stress
  • Reliability
  • Security
  • Unused flags
  • Not implemented errors
  • Inconsistent error handling
  • Performance
  • Multi-threading issues
  • Improper errors
What are the tools used for API test automation?

While testing Unit and API testing,  both target source code, if an API method is using code  based on .NET then the tool which is supporting should have .NET

Automation tools for API testing can be used are

  • NUnit for .NET
  • JUnit for Java
  • HP UFT
  • Soap UI
Mention the steps for testing API ?

API testing steps

  • Select the test case that has to be fulfilled
  • For API call develop a test case
  • To meet the test case configure the API parameters
  • Determine how will you validate a successful test
  • Using programming language like PHP or .NET execute the API call
  • Allow the API call to return the data to validate
What are the common protocols that are testing in API tesing ?
  • HTTP
  • JMS
  • REST
  • SOAP
  • UDDI

API testing Interview Questions and Answers PDF Download

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API testing Interview Questions
API testing interview questions and answers most asked at top companies. These API testing questions are for both experienced & fresher candidates PDF Download Free.

List of API testing Interview Questions and Answers PDF

What is API testing?

API (Application Programming Interface) specifies how some software components should interact with other, in other words it’s a set of functions and procedures that allows the creation of applications which access the features or data of an application or operating system.   Testing of these functions is known as API testing.

What are the tools used for API testing?

The tools used for various API testing are

  • SoapUI Pro
  • LoadUI Pro
  • Alertsite API monitoring
What are the common tests performed on API’s?

The common tests performed on API’s

  • Verification of the API whether it is updating any data structure
  • Verify if the API does not return anything
  • Based on input conditions, returned values from the API’s are checked
  • Verification of the API whether it triggers some other event or calls another API
Mention the key difference between UI level testing and API testing?

UI ( User Interface) refers to testing graphical interface such as how user interacts with the applications, testing application elements like fonts, images, layouts etc. UI testing basically focuses on look and feel of an application.

While, API enables communication between two separate software systems. A software system implementing an API contains functions or sub-routines that can be executed by another software system

Explain what is SOAP?

SOAP-stands for Simple Object Access Control, and it is an XML based protocol for exchanging information between computers.

Explain what is REST API?

It is a set of functions to which the developers performs requests and receive responses. In REST API interaction is made via HTTP protocol

REST – stands for Representational State Transfer, it is quickly becoming defacto standard for API creation.

Difference API and Unit Testing?
                       API testing                          UNIT testing
  • API is owned by QA team
  • Unit testing is owned by development team
  • API is mostly black box testing
  • Unit testing is white box testing
  • Full functionality of the system is considered in API testing as it will be used by the end-user (external developers who will use your API )
  • Unit testing is done to verify whether each unit in isolation performs as expected or not
  • API test are often run after the build is ready and authors do not have access to the source code
  • For each of their module the developers are expected to build unit tests for each of their code modules and have to ensure that each module pass unit test before the code is included in a build
How to test API’s ?

To test the API’s you should follow the following steps

  • Select the suite in which you want to add the API test case
  • Choose test development mode
  • Develop test cases for the desired API methods
  • Configure application control parameters
  • Configure test conditions
  • Configure method validation
  • Execute API test
  • View test reports
  • Filter API test cases
  • Sequence API test cases
Mention what the main areas to be taken in consideration while writing API document ?

The key area to be considered when writing API documents are

  • Source of the content
  • Document plan or sketch
  • Delivery layout
  • Information required for each function in the document
  • Automatic document creation programs
In API document explain how to document each function ?What are the tools used for documentation?
  • Description: Small description about what a function does
  • Syntax: Syntax about the parameter of the code, the sequence in which they occur, required and optional elements etc.
  • Parameters: Functions parameters
  • Error Messages: Syntax of error messages
  • Example Code: Small snippet of code
  • Related Links: Related functions

Popular tools used for API documentations are JavaDoc (for Java code ) Doxygen (for .Net code)

Explain API framework?

API framework is self-explanatory. Values for test run and for holding the configurable parts, config file is used.  Automated test cases must represent in “ parse-table” format within config file.  When testing API, it is not necessary to test each API so the config file have some section whose all API are activated for that specific run.

How does the API Builder work?

API Builder is a PLSQL program consists of four SQL files

  • For setting API parameters and starting the process one file is responsible
  • Two files are created for temporary tables and Master package to create the outputted code
  • Fourth file creates “spooled” output of the code into a file called “output_script_.sql”
Explain what is TestApi ?

TestApi is a library of utility and test APIs that enables testers and developers to create testing tools and automated tests for .NET and Win32 application.  It provides a set of common test building blocks, types, data-structure and algorithms.

What is Input injection and what are different ways of doing it ?

Input Injection:  It is the act of simulating user input, in several ways you can simulate user input.

  • Direct Method Invocation
  • Invocation using an accessibility interface
  • Simulation using low-level input
  • Simulation using a device driver
  • Simulation using a robot
What are the main challenges of API testing?

The main challenges in API testing is

  • Parameter Selection
  • Parameter Combination
  • Call sequencing
What is API testing with runscope ?

Runscope is a web application that provides backend services and easy to use interface for testing APIs.

Explain what are the principles of API test design?

The principle for API test design are

  • Setup : Create objects, start services, initialize data etc
  • Execution: Steps to exercise API or scenario, also logging
  • Verification: Oracles to evaluate execution outcome
  • Reporting: Pass, failed or blocked
  • Clean up: Pre-test state
What are the types of Bugs will API testing finds?

The types of Bugs, API will find

  • Missing or duplicate functionality
  • Fails to handle error conditions gracefully
  • Stress
  • Reliability
  • Security
  • Unused flags
  • Not implemented errors
  • Inconsistent error handling
  • Performance
  • Multi-threading issues
  • Improper errors
What are the tools used for API test automation?

While testing Unit and API testing,  both target source code, if an API method is using code  based on .NET then the tool which is supporting should have .NET

Automation tools for API testing can be used are

  • NUnit for .NET
  • JUnit for Java
  • HP UFT
  • Soap UI
Mention the steps for testing API ?

API testing steps

  • Select the test case that has to be fulfilled
  • For API call develop a test case
  • To meet the test case configure the API parameters
  • Determine how will you validate a successful test
  • Using programming language like PHP or .NET execute the API call
  • Allow the API call to return the data to validate
What are the common protocols that are testing in API tesing ?
  • HTTP
  • JMS
  • REST
  • SOAP
  • UDDI

Apache Storm Interview Questions and Answers PDF Download

Read Apache Storm Interview Questions and Answers for Interview PDF

Apache Storm Interview Questions
Apache Storm interview questions and answers most asked at top companies. These Apache Storm questions are for both experienced & fresher candidates PDF Download Free.

List of Apache Storm Interview Questions and Answers PDF

What is Autocad?

Autocad is a software program built to design and shape the 2-D and 3-D images.  It provides the tools by which a detail design of the product can be done. It also has the option to create detailed design layout, which can be automatically drawn by using source model.

What are the uses of Autocad?

Autocad can be used by the professionals to visualize the imaginary view of the product on a computer system. In Autocad, it is possible by the drafter to make the changes in the product before it gets finalized for design. It also gives the freedom for the designer to implement their various ideas and represent them to the suppliers or their clients.

What are the fields where you see maximum use of Autocad?

Autocad is more popular among the architects, engineers and builders for developing their building layouts.

What is the file formats used in design?

In Autocad, .dwg file format is used for design, it can be an interchangeable format.  The file format which is interchangeable has the extension as DXF and operates data operability. It provides different languages which can be used as per the requirement.

How you can create a user interface in Autocad?

User interface can be created by using the command prompts to draw the plots and dialog boxes. The dialog boxes can be displayed by the use of PLOT command and the external database commands (ASE).  Setting of CMDDIA to 1, allows the dialog boxes to run the command.  The user interface creation also needs the command line to display the entire file so that it can be edited or customized easily.

What is the function of vertical integration?

To enhance the architectural designing of 3D object Autocad uses the vertical integration program.  The 3D objects can include walls and other things that are associated with the data having information and simple objects like lines and circles. The data is programmed in such away that it represents only the architectural products and the extracted files, and can be modified according to the requirement.

What is the use of variant in Autocad?

In Autocad variants are used to help in creation, visualizing and rendering the 3D models that include 3D printing as well.  Variants allows you to use the functionality of different application according to the requirement.

What are the benefits of using Autocad?

Autocad has replaced the traditional method of drafting and designing which was made by pencil, drafting boards, triangles and compass with just a set of a computer program.  The benefits are immense like:

  • Saves time and helps to increase the productivity
  • It helps to streamline your design and documentation workflow
  • Physical ‘3D’ prototype of the design can be quickly created by using Autocad
  • 3D models can be directly imported into Autocad by using application like SolidWorks
  • Tedious work of drafting can be done easily and you can design and re-design the product in short span of time.
What is the process to draw a line more than one time and save it automatically?

When a need arises to draw a new line the process opens up a new file in a new session to write the file. Autocad allows saving multiple drawing for each session. The files are saved by using the file extension .dwg and it can be modified by using the browser.

What are the steps that enable the drag and drop feature in Autocad?

Autocad provides a way to drag and drop the elements by the use of “NOUN” and “VERB” in a dialog box.  It allows the object to move from one place to another.  Likewise, the remove or editing function can be done by using “MOVE and ERASE”.

What are the features corrected by Autocad?

Autocad detects the problem and correct it by removing the corruption with the drawing parts.  With the available option of adding additional vertices, it also adds vertices to the poly-lines. The error can be corrected or neglected by finding out the exact location of the poly-line that has zero vertices.  The object can be deleted or removed after there is no use of it in the system.

How to set up a default drawing directory?

Default drawing directory has sub directories having the information using the windows commands. The applications, which are going to be used, are highlighted, and by using drag and drop features those application will be placed in the default directory. The properties for the application are selected from the menu and dialog boxes displayed on the front.

How you can copy a closed drawing?

The copying of the closed drawing can be done by the designer center in the toolbar of the Autocad.  By using the tree view option the copy of closed drawing can be done easily. The modification of the drawing can be done by using graphical interface.

How you can hide the specific layers when plotting in Autocad?

To hide the specific layers while plotting, you can use various options like turning off the layers for plotting , freezing the layers and turning off. Turning off for plotting will show the layers on the screen but won’t output on printing. The layers that are turned off will hide the layers and also it will not appear on the screen.

What is the process of copying the dimension styles from one drawing to another in Autocad?

Copying of dimension styles require setting up the particular dimension style. To copy a dimension style, a new document has to be created. Once it is created, this document will be saved as a drawing template. A new reference will be created by new drawing template document and it will show all the options like layer style, units and blocks. Drawing can be done by seeing the current drawing and dimension style would be same as the original picture. By using the design center, Autocad tools can be used to copy the dimension styles from one drawing to another.

How can you remove the empty layers from drawing?

The layers can be removed only when the object resides in the layers will be removed, once it is removed it is an empty layer. The empty layers cannot be deleted by purge. It might be because the layer is frozen on a viewport or referenced by an object in a block definition. By using EXPORT command it is possible to remove the layer from drawing, which results in creating a DXF file of the drawing. You can edit the dxf file in a text editor and rename all the instances of layers in the file, except the layer definition.

Why Autocad WS is more popular among mobile users?

Autocad WS provides many option for mobile application developer like edit, view and share.  They can easily share the application wherever they go and can develop an application in a matter of time. The application can be downloaded and installed from anywhere in the world, ignoring the licensing problem. The users can save file in any format and can run the application on any platform with ease.

How can you make a spring, spiral or screw thread?

To make a spiral or screw thread use an AutoLISP routine such as spiral.1sp, it will create a spiral path according to your need. Then you can use EXTRUDE command with a reference object, using the spiral as the path.  Also, there is another way you can do this, by using Mechanical Desktop (MDT) or Autosurf by using augmented lines as path.

Tell me how you assign the keyboard characters or function keys to Autocad commands?

By editing the ACCELERATORS section of the Autocad menu file we can assign keyboard characters to Autocad commands.

How you can open a drawing file that was created with the automatic save features?

Autocad files have an extension of “.dwg” and will only open those files having this extension. To open the drawing files you have to rename it, by using Explorer or DOS prompt you can do that. If you are using EXPLORER you have to make sure that the option of “Hide file extensions for known file types” is not enabled. After the file is copied you can rename and use the OPEN command in Autocad to open the drawing.

What will you do when command prompts appear on the command line instead of ASE dialog box and plot dialog box?

In Autocad, CMDDIA variable controls the display of dialog boxes. To enable these dialog boxes you have to set CMDDIA to 1.

In Autocad, what is the command that is used to rotate the grid at 45 degress?

To rotate the grid at 45 degrees, command UCS is used.

In what situation command prompt appears instead of a dialog boxes?

If a file command is imported from a script or AutoLISP/ ObjectARX/ ADSRX a command prompt appears instead of a dialog box.

What are grips?

Grips are small boxes that appear on the objects you select.  You can move or edit an object by dragging a grip.

What you are supposed to do when “Enter Attributes” dialogue doesn’t display?

In this case, two variable controls this function, ATTREQ and ATTDIA , to see the “Enter Attributes” dialogue , make sure both the variables are set to 1 and not 0.

Explain what is Apache Storm? What are the components of Storm?

Apache storm is an open source distributed real-time computation system used for processing real time big data analytics. Unlike Hadoop batch processing, Apache storm does for real-time processing and can be used with any programming language.

Components of Apache Storm includes

  • Nimbus: It works as a Hadoop’s Job Tracker. It distributes code across the cluster, uploads computation for execution, allocate workers across the cluster and monitors computation and reallocates workers as needed
  • Zookeeper: It is used as a mediator for communication with the Storm Cluster
  • Supervisor: Interacts with Nimbus through Zookeeper, depending on the signals received from the Nimbus, it executes the process.
Why Apache Storm is the first choice for Real Time Processing?
  • Easy to operate: Operating storm is quiet easy
  • Real fast: It can process 100 messages per second per node
  • Fault Tolerant: It detects the fault automatically and re-starts the functional attributes
  • Reliable: It guarantees that each unit of data will be executed at least once or exactly once
  • Scalable: It runs across a cluster of machine
Explain how data is stream flow in Apache Storm?

In Apache storm, data is stream flow with three components Spout, Bolt andTuple

  • Spout: A spout is a source of data in Storm
  • Bolt: A bolt processes these data’s
  • Tuple: Data is passed as Tuple
Mention what is the difference between Apache Hbase and Storm?
   Apache Storm                               Apache Hbase
  • It provides data processing in real-time
  • It processes the data but not store
  • You will streamline your data where data is processed in real time, so that alerts and actions can be raised if needed
  •  It offers you low-latency reads of processed data for querying later
  • It stores the data but does not store
  •  ______________
Explain how you can streamline log files using Apache storm?

To read from the log files you can configure your spout and emit per line as it read the log.  The output then can be assign to a bolt for analyzing.

Explain what streams is and stream grouping in Apache storm?

In Apache Storm, stream is referred as a group or unbounded sequence of Tuples while stream grouping determines how stream should be partitioned among the bolt’s tasks.

List out different stream grouping in Apache storm?
  • Shuffle grouping
  • Fields grouping
  • Global grouping
  • All grouping
  • None grouping
  • Direct grouping
  • Local grouping
Mention how storm application can be beneficial in financial services?

In financial services, Storm can be helpful in preventing

  • Securities fraud
  • Order routing
  • Pricing
  • Compliance Violations
What is Topology_Message_Timeout_secs in Apache Storm?

The maximum amount of time alloted to the topology to fully process a message released by a spout. If the message in not acknowledged in given time frame, Apache storm will fail the message on the spout.

How message is fully processed in Apache Storm?

By calling the nextTuple procedure or method on the Spout, Storm requests a tuple from the Spout.  The Spout avails the SpoutoutputCollector given in the open method to discharge a tuple to one of its output streams. While discharging a tuple, the Spout allocates a “message id” that will be used to recognize the tuple later.

After that, the tuple gets sent to consuming bolts, and storm takes charge of tracking the tree of messages that is produced.  If the storm is confident that a tuple is processed thoroughly, then it can call the ack procedure on the originating Spout task with the message id that the Spout has given to the Storm

How to write the Output into a file using Storm?

In Spout, when you are reading file, make FileReader object in Open()method, as such that time it initializes the reader object for worker node. And use that object in nextTuple() method.

What is the difference between Apache Kafka and Apache Storm?
  • Apache Kafka: It is a distributed and robust messaging system that can handle huge amount of data and allows passage of messages from one end-point to another.
  • Apache Storm: It is a real time message processing system, and you can edit or manipulate data in real time. Apache storm pulls the data from Kafka and applies some required manipulation.
Explain when using field grouping in storm, is there any time-out or limit to known field values?

Field grouping in storm uses a mod hash function to decide which task to send a tuple, ensuring which task will be processed in the correct order. For that, you don’t require any cache.  So, there is no time-out or limit to known field values.

SAS Interview Questions and Answers PDF Download

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SAS Interview Questions
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List of SAS Interview Questions and Answers PDF

What areas of SAS are you most interested in?

BASE, STAT, GRAPH, ETS.

Describe 5 ways to do a “table lookup” in SAS.

Match Merging, Direct Access, Format Tables, Arrays, PROC SQL

What versions of SAS have you used (on which platforms)?

SAS 9.1.3,9.0, 8.2 in Windows and UNIX, SAS 7 and 6.12

What are some good SAS programming practices for processing very large data sets?

Sampling method using OBS option or subsetting, commenting the Lines, Use Data Null

What are some problems you might encounter in processing missing values? In Data steps? Arithmetic? Comparisons? Functions? Classifying data?

The result of any operation with missing value will result in missing value. Most SAS statistical procedures exclude observations with any missing variable values from an analysis.

How would you create a data set with 1 observation and 30 variables from a data set with 30 observations and 1 variable?

Using PROC TRANSPOSE

What is the different between functions and PROCs that calculate the same simple descriptive statistics?

Proc can be used with wider scope and the results can be sent to a different dataset. Functions usually affect the existing datasets.

If you were told to create many records from one record, show how you would do this using array and with PROC TRANSPOSE?

Declare array for number of variables in the record and then used Do loop Proc Transpose with VAR statement

What do the SAS log messages “numeric values have been converted to character” mean? What are the implications?

It implies that automatic conversion took place to make character functions possible.

Why is a STOP statement needed for the POINT= option on a SET statement?

Because POINT= reads only the specified observations, SAS cannot detect an end-of-file condition as it would if the file were being read sequentially.

How do you control the number of observations and/or variables read or written?

FIRSTOBS and OBS option

Approximately what date is represented by the SAS date value of 730?

31st December 1961

Identify statements whose placement in the DATA step is critical.

INPUT, DATA and RUN…

What does the RUN statement do?

When SAS editor looks at Run it starts compiling the data or proc step, if you have more than one data step or proc step or if you have a proc step. Following the data step then you can avoid the usage of the run statement.

Why is SAS considered self-documenting?

SAS is considered self documenting because during the compilation time it creates and stores all the information about the data set like the time and date of the data set creation later No. of the variables later labels all that kind of info inside the dataset and you can look at that info using proc contents procedure.

What are some good SAS programming practices for processing very large data sets?

Sort them once, can use firstobs = and obs = ,

What is the different between functions and PROCs that calculate thesame simple descriptive statistics?

Functions can used inside the data step and on the same data set but with proc’s you can create a new data sets to output the results. May be more ………..

If you were told to create many records from one record, show how you would do this using arrays and with PROC TRANSPOSE?

I would use TRANSPOSE if the variables are less use arrays if the var are more …………….. depends

What is a method for assigning first.VAR and last.VAR to the BY groupvariable on unsorted data?

In unsorted data you can’t use First or Last.

How do you debug and test your SAS programs?

First thing is look into Log for errors or warning or NOTE in some cases or use the debugger in SAS data step.

What other SAS features do you use for error trapping and datavalidation?

Check the Log and for data validation things like Proc Freq, Proc means or some times proc print to look how the data looks like ……..

How would you combine 3 or more tables with different structures?

I think sort them with common variables and use merge statement. I am not sure what you mean different structures.

What are _numeric_ and _character_ and what do they do?

Will either read or writes all numeric and character variables in dataset.

For what purpose would you use the RETAIN statement?

The retain statement is used to hold the values of variables across iterations of the data step. Normally, all variables in the data step are set to missing at the start of each iteration of the data step. What is the order of evaluation of the comparison operators: + – * / ** ()?A) (), **, *, /, +, –

How could you generate test data with no input data?

Using Data Null and put statement

How do you debug and test your SAS programs?

Using Obs=0 and systems options to trace the program execution in log.

What can you learn from the SAS log when debugging?

It will display the execution of whole program and the logic. It will also display the error with line number so that you can and edit the program.

What is the purpose of error?

It has only to values, which are 1 for error and 0 for no error.

How do you test for missing values?

Using Subset functions like IF then Else, Where and Select.

In the flow of DATA step processing, what is the first action in a typical DATA Step?

When you submit a DATA step, SAS processes the DATA step and then creates a new SAS data set.( creation of input buffer and PDV)
Compilation Phase
Execution Phase

What are SAS/ACCESS and SAS/CONNECT?

SAS/Access only process through the databases like Oracle, SQL-server, Ms-Access etc. SAS/Connect only use Server connection.

What is the one statement to set the criteria of data that can be coded in any step?

OPTIONS Statement, Label statement, Keep / Drop statements.

What is the purpose of using the N=PS option?

The N=PS option creates a buffer in memory which is large enough to store PAGESIZE (PS) lines and enables a page to be formatted randomly prior to it being printed.

What are the scrubbing procedures in SAS?

Proc Sort with nodupkey option, because it will eliminate the duplicate values.

What are the new features included in the new version of SAS i.e., SAS9.1.3?

The main advantage of version 9 is faster execution of applications and centralized access of data and support.

There are lots of changes has been made in the version 9 when we compared with the version 8. The following are the few:SAS version 9 supports Formats longer than 8 bytes & is not possible with version 8.

Length for Numeric format allowed in version 9 is 32 where as 8 in version 8.
Length for Character names in version 9 is 31 where as in version 8 is 32.
Length for numeric informat in version 9 is 31, 8 in version 8.
Length for character names is 30, 32 in version 8.3 new informats are available in version 9 to convert various date, time and datetime forms of data into a SAS date or SAS time.

•ANYDTDTEW. – Converts to a SAS date value
•ANYDTTMEW. – Converts to a SAS time value.
•ANYDTDTMW. -Converts to a SAS datetime value.
•CALL SYMPUTX Macro statement is added in the version 9 which creates a macro variable at execution time in the data step by Trimming trailing blanks. Automatically converting numeric value to character. New ODS option (COLUMN OPTION) is included to create a multiple columns in the output.

What do the PUT and INPUT functions do?

INPUT function converts character data values to numeric values.
PUT function converts numeric values to character values.EX: for INPUT: INPUT (source, informat)

For PUT: PUT (source, format)

Note that INPUT function requires INFORMAT and PUT function requires FORMAT.

If we omit the INPUT or the PUT function during the data conversion, SAS will detect the mismatched variables and will try an automatic character-to-numeric or numeric-to-character conversion. But sometimes this doesn’t work because $ sign prevents such conversion. Therefore it is always advisable to include INPUT and PUT functions in your programs when conversions occur.

Which date function advances a date, time or datetime value by a given interval?

INTNX:

INTNX function advances a date, time, or datetime value by a given interval, and returns a date, time, or datetime value. Ex: INTNX(interval,start-from,number-of-increments,alignment)

INTCK: INTCK(interval,start-of-period,end-of-period) is an interval functioncounts the number of intervals between two give SAS dates, Time and/or datetime.

DATETIME () returns the current date and time of day.

DATDIF (sdate,edate,basis): returns the number of days between two dates.

How might you use MOD and INT on numeric to mimic SUBSTR on character Strings?

The first argument to the MOD function is a numeric, the second is a non-zero numeric; the result is the remainder when the integer quotient of argument-1 is divided by argument-2. The INT function takes only one argument and returns the integer portion of an argument, truncating the decimal portion. Note that the argument can be an expression.

DATA NEW ;
A = 123456 ;
X = INT( A/1000 ) ;
Y = MOD( A, 1000 ) ;
Z = MOD( INT( A/100 ), 100 ) ;
PUT A= X= Y= Z= ;
RUN ;
Result:
A=123456
X=123
Y=456
Z=34

In ARRAY processing, what does the DIM function do?

DIM: It is used to return the number of elements in the array. When we use Dim function we would have to re –specify the stop value of an iterative DO statement if u change the dimension of the array.

How would you determine the number of missing or nonmissing values in computations?

To determine the number of missing values that are excluded in a computation, use the NMISS function.

data _null_;
m = . ;
y = 4 ;
z = 0 ;
N = N(m , y, z);
NMISS = NMISS (m , y, z);
run;

The above program results in N = 2 (Number of non missing values) and NMISS = 1 (number of missing values).

Do you need to know if there are any missing values?

Just use: missing_values=MISSING(field1,field2,field3);
This function simply returns 0 if there aren’t any or 1 if there are missing values.If you need to know how many missing values you have then use num_missing=NMISS(field1,field2,field3);
You can also find the number of non-missing values with non_missing=N (field1,field2,field3);

What are the validation tools in SAS?

For dataset: Data set name/debugData set: name/stmtchk
For macros: Options:mprint mlogic symbolgen.

How can you put a “trace” in your program?

ODS Trace ON, ODS Trace OFF the trace records.

How would you code a merge that will keep only the observations that have matches from both data sets?

Using “IN” variable option. Look at the following example.
data three;
merge one(in=x) two(in=y);
by id;
if x=1 and y=1;
run;
*or;

data three;
merge one(in=x) two(in=y);
by id;
if x and y;
run;

What are input dataset and output dataset options?

Input data set options are obs, firstobs, where, in output data set options compress, reuse.Both input and output dataset options include keep, drop, rename, obs, first obs.

What is SAS GRAPH?

SAS/GRAPH software creates and delivers accurate, high-impact visuals that enable decision makers to gain a quick understanding of critical business issues.