Nvidia Interview Questions and Answers for Technical Profiles

Nvidia Corporation, an American technology company based in Santa Clara, California, is a leading designer of graphics processing units (GPUs) for the gaming, cryptocurrency, and professional markets. It also designs system-on-a-chip (SoC) units for the mobile computing and automotive markets.

If you’re interviewing for a technical role at Nvidia, it’s important to be prepared for a variety of questions on topics such as data structures, algorithms, operating systems, and machine learning.

In this article, we’ve compiled a list of the most common Nvidia technical interview questions and answers. We hope this helps you prepare for your next interview and land your dream job at Nvidia!

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1. What is the difference between lemming vs stemming?
Natural Language Processing (NLP) is a broad subfield of Artificial Intelligence that deals with processing and predicting textual data. While Python is known for the extensive libraries it offers for various ML/DL tasks – it certainly doesn’t fail to do so for NLP tasks.

2. What is the OS? What are the various functions of OS?
An Operating System acts as a communication bridge (interface) between the user and computer hardware.

Functions of an Operating System

• Memory Management: The operating system manages the Primary Memory or Main Memory. Main memory is made up of a large array of bytes or words where each byte or word is assigned a certain address
• Processor Management: In a multi-programming environment, the OS decides the order in which processes have access to the processor, and how much processing time each process has.
• Device Management: An OS manages device communication via its respective drivers. It performs the following activities for device management.
• File Management: A file system is organized into directories for efficient or easy navigation and usage. These directories may contain other directories and other files. An Operating System carries out the following file management activities.
• User Interface or Command Interpreter: The user interacts with the computer system through the operating system. Hence OS acts as an interface between the user and the computer hardware.

3. Difference between logistic and linear regression?

Linear Regression	Logistic Regression
Here no activation function is used.	Here activation function is used to convert a linear regression equation to the logistic regression equation
Here no threshold value is needed.	Here no threshold value is needed.
Here we calculate Root Mean Square Error(RMSE) to predict the next weight value.	Here we calculate Root Mean Square Error(RMSE) to predict the next weight value.
Here dependent variable should be numeric and the response variable is continuous to value.	Here dependent variable should be numeric and the response variable is continuous to value.
It is based on the least square estimation.	It is based on the least square estimation.

4. Difference between Multi-Level Queue Scheduling (MLQ) and Priority Scheduling

Multi-level queue scheduling (MLQ)	Priority scheduling
Processes are executed depending on the priority of that particular level of queue to which the process belongs. Further selection of process is based upon the multi-level type of algorithm used in that particular queue.	It executes processes based upon their priorities i.e. in descending order of their priorities. A process with higher priority is executed first.
It can be both non-preemptive and preemptive in nature depending upon conditions.	It is both preemptive and non-preemptive in nature.
Average waiting time and average response time depend upon algorithms used in various levels of multi-level queues for scheduling.	There is no idea of the average waiting time and response time.
It leads to starvation of processes at lower levels of multi-level queues.	The problem of blocking a process can be solved through aging which means gradually increasing the priority of a process after a fixed interval of time by a fixed number.

5. What is a Static variable and where it is stored?
Static variables have the property of preserving their value even after they are out of their scope! Hence, a static variable preserves its previous value in its previous scope and is not initialized again in the new scope. 

Syntax:

static data_type var_name = var_value;

6. What is a deadlock?
A deadlock is a situation where a set of processes are blocked because each process is holding a resource and waiting for another resource acquired by some other process.

7. What is the difference between stacks or queues?
Stack: A stack is a linear data structure in which elements can be inserted and deleted only from one side of the list, called the top. A stack follows the LIFO (Last In First Out) principle, i.e., the element inserted at the last is the first element to come out. 

ueue: ueue is a linear data structure in which elements can be inserted only from one side of the list called rear, and the elements can be deleted only from the other side called the front.

Stacks	Queues
A stack is a data structure that stores a collection of elements, with operations to push (add) and pop (remove) elements from the top of the stack.	A queue is a data structure that stores a collection of elements, with operations to enqueue (add) elements at the back of the queue, and dequeue (remove) elements from the front of the queue.
Stacks are based on the LIFO principle, i.e., the element inserted at the last, is the first element to come out of the list.	Queues are based on the FIFO principle, i.e., the element inserted at the first, is the first element to come out of the list.
Stacks are often used for tasks that require backtracking, such as parsing expressions or implementing undo functionality.	Queues are often used for tasks that involve processing elements in a specific order, such as handling requests or scheduling tasks.
Insertion and deletion in stacks takes place only from one end of the list called the top.	Insertion and deletion in queues takes place from the opposite ends of the list. The insertion takes place at the rear of the list and the deletion takes place from the front of the list.
Insert operation is called push operation.	Insert operation is called enqueue operation.

8. How to implement a queue using stack?

(By making enQueue operation costly): This method makes sure that oldest entered element is always at the top of stack 1, so that deQueue operation just pops from stack1. To put the element at top of stack1, stack2 is used.

enQueue(q, x): 

• While stack1 is not empty, push everything from stack1 to stack2.
• Push x to stack1 (assuming size of stacks is unlimited).
• Push everything back to stack1.

Here time complexity will be O(n)

deQueue(q): 

• If stack1 is empty then error
• Pop an item from stack1 and return it

Here time complexity will be O(1)

9. Binary Search on Singly Linked List
To perform a Binary search on a Linked List, the most important idea is to find the middle element of the Linked List on every iteration, which takes O(N) time everytime. This can be avoided if skip list is used.

10. What is Binary Tree ?
Binary Tree is defined as a tree data structure where each node has at most 2 children. Since each element in a binary tree can have only 2 children, we typically name them the left and right child.

11. What is CUDA?
CUDA stands for Compute Unified Device Architecture. It is an extension of C/C++ programming. CUDA is a programming language that uses the Graphical Processing Unit (GPU). It is a parallel computing platform and an API (Application Programming Interface) model, Compute Unified Device Architecture was developed by Nvidia.

12. Explain how a ROC curve works.
One important aspect of Machine Learning is model evaluation. You need to have some mechanism to evaluate your model. This is where these performance metrics come into the picture they give us a sense of how good a model is.

13. What is Ploymorphism?
The word “polymorphism” means having many forms. In simple words, we can define polymorphism as the ability of a message to be displayed in more than one form. 

14. What is the Socket Programming?
Socket programming is a way of connecting two nodes on a network to communicate with each other. One socket(node) listens on a particular port at an IP, while the other socket reaches out to the other to form a connection.

15. What is an IP Address?
All the computers of the world on the Internet network communicate with each other with underground or underwater cables or wirelessly. If I want to download a file from the internet or load a web page or literally do anything related to the internet, my computer must have an address so that other computers can find and locate mine in order to deliver that particular file or webpage that I am requesting. In technical terms, that address is called IP Address or Internet Protocol Address.

16.  Virtual Memory 
Virtual Memory is a storage allocation scheme in which secondary memory can be addressed as though it were part of the main memory.

17. Difference between mutex and semaphore?

Mutex	Semaphore
A mutex is an object.	A semaphore is an integer.
Mutex works upon the locking mechanism.	Semaphore uses signaling mechanism
Operations on mutex: Lock Unlock	Operation on semaphore: Wait Signal
Mutex doesn’t have any subtypes.	Semaphore is of two types: Counting Semaphore Binary Semaphore
A mutex can only be modified by the process that is requesting or releasing a resource.	Semaphore work with two atomic operations (Wait, signal) which can modify it.

18. Precision and Recall in Information Retrieval
Information Systems can be measured with two metrics: precision and recall. When a user decides to search for information on a topic, the total database and the results to be obtained can be divided into 4 categories:

1. Relevant and Retrieved
2. Relevant and Not Retrieved
3. Non-Relevant and Retrieved
4. Non-Relevant and Not Retrieved

19. What is the difference between Trigger and Stored Procedure? 

Parameters	Triggers	Procedures
Basics	A Trigger is implicitly invoked whenever any event such as INSERT, DELETE, or UPDATE occurs in a TABLE.	A Procedure is explicitly called by the user/application using statements or commands such as exec, EXECUTE, or simply procedure name
Action	When an event occurs, a trigger helps to execute an action automatically.	A procedure helps to perform a specified task when it is invoked.
Define/ call	Only nesting of triggers can be achieved in a table. We cannot define/call a trigger inside another trigger.	We can define/call procedures inside another procedure.
Syntax	In a database, the syntax to define a trigger: CREATE TRIGGER TRIGGER_NAME	In a database, the syntax to define a procedure: CREATE PROCEDURE PROCEDURE_NAME
Transaction statements	Transaction statements such as COMMIT, ROLLBACK, and SAVEPOINT are not allowed in triggers.	All transaction statements such as COMMIT and ROLLBACK are allowed in procedures

20. What is Denormalization?
Denormalization is a database optimization technique in which we add redundant data to one or more tables.

21. Sort an array of 0s, 1s and 2s

The problem is similar to “Segregate 0s and 1s in an array”.

• The problem was posed with three colors, here `0′, `1′ and `2′. The array is divided into four sections: 
  • arr[1] to arr[low – 1]
  • arr[low] to arr[mid – 1]
  • arr[mid] to arr[high – 1]
  • arr[high] to arr[n]
• If the ith element is 0 then swap the element to the low range.
• Similarly, if the element is 1 then keep it as it is.
• If the element is 2 then swap it with an element in high range.

22. Reverse a Linked List
The idea is to use three pointers curr, prev, and next to keep track of nodes to update reverse links.

23. Binary Search
Binary Search is defined as a searching algorithm used in a sorted array by repeatedly dividing the search interval in half. The idea of binary search is to use the information that the array is sorted and reduce the time complexity to O(log N). 

24. Tree Traversal 

Inorder Traversal

Algorithm Inorder(tree)

1. Traverse the left subtree, i.e., call Inorder(left->subtree)
2. Visit the root.
3. Traverse the right subtree, i.e., call Inorder(right->subtree)

Preorder Traversal

Algorithm Preorder(tree)

1. Visit the root.
2. Traverse the left subtree, i.e., call Preorder(left->subtree)
3. Traverse the right subtree, i.e., call Preorder(right->subtree) 

Postorder Traversal

Algorithm Postorder(tree)

1. Traverse the left subtree, i.e., call Postorder(left->subtree)
2. Traverse the right subtree, i.e., call Postorder(right->subtree)
3. Visit the root

25. What is convolution ?
Convolutions are one of the key features behind Convolutional Neural Networks. For the details of working of CNNs, refer to Introduction to Convolution Neural Network. Feature Learning Feature Engineering or Feature Extraction is the process of extracting useful patterns from input data that will help the prediction model to understand better the real nature of the problem.

26. Binary Search on Singly Linked List
To perform a Binary search on a Linked List, the most important idea is to find the middle element of the Linked List on every iteration, which takes O(N) time everytime. This can be avoided if skip list is used.

27. What is VPN?
VPN stands for the virtual private network. A virtual private network (VPN) is a technology that creates a safe and encrypted connection over a less secure network, such as the Interne

28. What is IP Spoofing?
IP Spoofing is essentially a technique used by hackers to gain unauthorized access to Computers. Concepts of IP Spoofing were initially discussed in academic circles as early as 1980. 

29. What is the difference between Bluetooth and wifi? 

Bluetooth	Wifi
Bluetooth has no full form.	While Wifi stands for Wireless Fidelity.
It requires a Bluetooth adapter on all devices for connectivity.	Whereas it requires a wireless adapter Bluetooth for all devices and a wireless router for connectivity.
Bluetooth consumes low power.	while it consumes high power.
The security of BlueTooth is less in comparison to the number of wifi.	While it provides better security than BlueTooth.
Bluetooth is less flexible means these limited users are supported.	Whereas wifi supports a large number of users.
The radio signal range of BlueTooth is ten meters.	Whereas in wifi this range is a hundred meters.

30. Difference between Demand Paging and Segmentation

Demand Paging	Segmentation
In demand paging, the pages are of equal size.	While in segmentation, segments can be of different size.
Page size is fixed in the demand paging.	Segment size may vary in segmentation as it grants dynamic increase of segments.
It does not allows sharing of the pages.	While segments can be shared in segmentation.
In demand paging, on demand pages are loaded in the memory.	In segmentation, during compilation segments are allocated to the program.
Page map table in demand paging manages record of pages in memory.	Segment map table in segmentation demonstrates every segment address in the memory.

31. ACID Properties
A transaction is a single logical unit of work that accesses and possibly modifies the contents of a database. Transactions access data using read and write operations. 
In order to maintain consistency in a database, before and after the transaction, certain properties are followed. These are called ACID properties. 

• Atomicity
• Consistency
• Isolation
• Durability

32. Difference between DELETE and TRUNCATE

Delete	Truncate
The DELETE command is used to delete specified rows(one or more).	While this command is used to delete all the rows from a table.
It is a DML(Data Manipulation Language) command.	While it is a DDL(Data Definition Language) command.
There may be a WHERE clause in the DELETE command in order to filter the records.	While there may not be WHERE clause in the TRUNCATE command.
In the DELETE command, a tuple is locked before removing it.	While in this command, the data page is locked before removing the table data.

33. Difference between Hub and Switch

HUB	SWITCH
Hub is operated on Physical layer of OSI model.	While switch is operated on Data link layer of OSI Model.
Hub is a broadcast type transmission.	While switch is a Unicast, multicast and broadcast type transmission.
Hub have 4/12 ports.	While switch can have 24 to 48 ports.
In hub, there is only one collision domain.	While in switch, different ports have own collision domain.
Hub is a half duplex transmission mode.	While switch is a full duplex transmission mode.

34. What is Fragmentation
The process of dividing a computer file, such as a data file or an executable program file, into fragments that are stored in different parts of a computer’s storage medium, such as its hard disc or RAM, is known as fragmentation in computing. 

35. What is the Firewall?
A firewall is a network security device, either hardware or software-based, which monitors all incoming and outgoing traffic and based on a defined set of security rules it accepts, rejects or drops that specific traffic

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